The 100 most-cited articles in Physical review. D/Physical review. D., 2019

The detection of gravitational waves by Advanced LIGO and Advanced Virgo provides an opportunity to test general relativity in a regime that is inaccessible to traditional astronomical observations and laboratory tests. We present four tests of the consistency of the data with binary black hole gravitational waveforms predicted by general relativity. One test subtracts the best-fit waveform from the data and checks the consistency of the residual with detector noise. The second test checks the consistency of the low- and high-frequency parts of the observed signals. The third test checks that phenomenological deviations introduced in the waveform model (including in the post-Newtonian coefficients) are consistent with 0. The fourth test constrains modifications to the propagation of gravitational waves due to a modified dispersion relation, including that from a massive graviton. We present results both for individual events and also results obtained by combining together particularly strong events from the first and second observing runs of Advanced LIGO and Advanced Virgo, as…

The presence of a bright ``photon ring'' surrounding a dark ``black hole shadow'' has been discussed as an important feature of the observational appearance of emission originating near a black hole. We clarify the meaning and relevance of these heuristics with analytic calculations and numerical toy models. The standard usage of the term ``shadow'' describes the appearance of a black hole illuminated from all directions, including from behind the observer. A backlit black hole casts a somewhat larger shadow. Neither ``shadow'' heuristic is particularly relevant to understanding the appearance of emission originating near the black hole, where the emission profile and gravitational redshift play the dominant roles in determining the observed size of the central dark area. A photon ring results from light rays that orbit around the black hole in the near-field region before escaping to infinity, where they arrive near a ring-shaped ``critical curve'' on the image plane. Although the brightness can become arbitrarily large near this critical curve in the case of optically thin…

The CRESST experiment is a direct dark matter search which aims to measure interactions of potential dark matter particles in an Earth-bound detector. With the current stage, CRESST-III, we focus on a low energy threshold for increased sensitivity towards light dark matter particles. In this paper we describe the analysis of one detector operated in the first run of CRESST-III (05/2016--02/2018) achieving a nuclear recoil threshold of 30.1 eV. This result was obtained with a 23.6 g ${\mathrm{CaWO}}_{4}$ crystal operated as a cryogenic scintillating calorimeter in the CRESST setup at the Laboratori Nazionali del Gran Sasso (LNGS). Both the primary phonon (heat) signal and the simultaneously emitted scintillation light, which is absorbed in a separate silicon-on-sapphire light absorber, are measured with highly sensitive transition edge sensors operated at $\ensuremath{\sim}15\text{ }\text{ }\mathrm{mK}$. The unique combination of these sensors with the light element oxygen present in our target yields sensitivity to dark matter particle masses as low as $160\text{ }\text{…

The Event Horizon Telescope (EHT) collaboration has recently released the first image of a black hole (BH), opening a new window onto tests of general relativity in the strong field regime. In this paper, we derive constraints on the nature of M87* (the supermassive object at the center of the galaxy M87), exploiting the fact that its shadow appears to be highly circular, and using measurements of its angular size. We first consider the simple case where M87* is assumed to be a Kerr BH. We find that the inferred circularity of M87* excludes Kerr BHs with observation angle ${\ensuremath{\theta}}_{\mathrm{obs}}\ensuremath{\gtrsim}45\ifmmode^\circ\else\textdegree\fi{}$ for dimensionless rotational parameter $0.95\ensuremath{\lesssim}{a}_{*}\ensuremath{\le}1$ whereas the observation angle is unbounded for ${a}_{*}\ensuremath{\lesssim}0.9$. We then consider the possibility that M87* might be a superspinar, i.e., an object described by the Kerr solution and spinning so fast that it violates the Kerr bound by having $|{a}_{*}|>1$. We find that, within certain regions of parameter space,…

In this work, we consider an extension of symmetric teleparallel gravity, namely, $f(Q)$ gravity, where the fundamental block to describe spacetime is the nonmetricity, $Q$. Within this formulation of gravitation, we perform an observational analysis of several modified $f(Q)$ models using the redshift approach, where the $f(Q)$ Lagrangian is reformulated as an explicit function of the redshift, $f(z)$. Various different polynomial parametrizations of $f(z)$ are proposed, including new terms which would allow for deviations from the $\mathrm{\ensuremath{\Lambda}}$ Cold Dark Matter model. Given a variety of observational probes, such as the expansion rate data from early type galaxies, type Ia supernovae, quasars, gamma ray bursts, baryon acoustic oscillations data, and cosmic microwave background distance priors, we have checked the validity of these models at the background level in order to verify if this new formalism provides us with plausible alternative models to explain the late time acceleration of the Universe. Indeed, this novel approach provides a different perspective on…

We constrain the abundance of primordial black holes (PBH) using 2622 microlensing events obtained from 5-years observations of stars in the Galactic bulge by the Optical Gravitational Lensing Experiment (OGLE). The majority of microlensing events display a single or at least continuous population that has a peak around the light curve timescale ${t}_{\mathrm{E}}\ensuremath{\simeq}20\text{ }\text{ }\mathrm{days}$ and a wide distribution over the range ${t}_{\mathrm{E}}\ensuremath{\simeq}[1,300]\text{ }\text{ }\mathrm{days}$, while the data also indicates a second population of 6 ultrashort-timescale events in ${t}_{\mathrm{E}}\ensuremath{\simeq}[0.1,0.3]\text{ }\text{ }\mathrm{days}$, which are advocated to be due to free-floating planets. We confirm that the main population of OGLE events can be well modeled by microlensing due to brown dwarfs, main sequence stars and stellar remnants (white dwarfs and neutron stars) in the standard Galactic bulge and disk models for their spatial and velocity distributions. Using the dark matter (DM) model for the Milky Way (MW) halo relative to…

This paper, using the Dark Energy Survey (DES) year 1 data, together with external data, seeks to constrain several extensions to LCDM models, that include adding extra relativistic degrees of freedom, curvature, a time dependent dark energy equation of state and modified gravity. The conclusion is that only the constraints on the parameters of modified gravity benefit significantly from including the DES year 1 data, making these consistent with predictions from general relativity.

We present a lattice QCD calculation of the double-virtual neutral pion transition form factor, with the goal to cover the kinematic range relevant to hadronic light-by-light scattering in the muon $g\ensuremath{-}2$. Several improvements have been made compared to our previous work. First, we take into account the effects of the strange quark by using the ${N}_{f}=2+1$ coordinated lattice simulation gauge ensembles. Second, we have implemented the on-shell $\mathcal{O}(a)$ improvement of the vector current to reduce the discretization effects associated with Wilson quarks. Finally, in order to have access to a wider range of photon virtualities, we have computed the transition form factor in a moving frame as well as in the pion rest frame. After extrapolating the form factor to the continuum and to physical quark masses, we compare our results with phenomenology. We extract the normalization of the form factor with a precision of 3.5% and confirm within our uncertainty previous somewhat conflicting estimates for a low-energy constant that appears in chiral perturbation theory for…

The Event Horizon Telescope has recently provided the first image of the dark shadow around the supermassive black hole M87*. The observation of a highly circular shadow provides strong limits on deviations of M87*'s quadrupole moment from the Kerr value. We show that the absence of such a deviation can be used to constrain the physics of extra dimensions of spacetime. Focusing on the Randall-Sundrum ${\mathrm{AdS}}_{5}$ brane-world scenario, we show that the observation of M87*'s dark shadow sets the limit $\ensuremath{\ell}\ensuremath{\lesssim}170\text{ }\text{ }\mathrm{AU}$, where $\ensuremath{\ell}$ is the ${\mathrm{AdS}}_{5}$ curvature radius. This limit is among the first quantitative constraints on exotic physics obtained from the extraordinary first ever image of the dark shadow of a black hole.

The ForwArd Search ExpeRiment (FASER) is an approved experiment dedicated to searching for light, extremely weakly interacting particles at the LHC. Such particles may be produced in the LHC's high-energy collisions and travel long distances through concrete and rock without interacting. They may then decay to visible particles in FASER, which is placed 480 m downstream of the ATLAS interaction point. In this work we briefly describe the FASER detector layout and the status of potential backgrounds. We then present the sensitivity reach for FASER for a large number of long-lived particle models, updating previous results to a uniform set of detector assumptions, and analyzing new models. In particular, we consider all of the renormalizable portal interactions, leading to dark photons, dark Higgs bosons, and heavy neutral leptons; light $B\ensuremath{-}L$ and ${L}_{i}\ensuremath{-}{L}_{j}$ gauge bosons; axionlike particles that are coupled dominantly to photons, fermions, and gluons through nonrenormalizable operators; and pseudoscalars with Yukawa-like couplings. We find that FASER…

When two black holes merge in a dense star cluster, they form a new black hole with a well-defined mass and spin. If that ``second-generation'' black hole remains in the cluster, it will continue to participate in dynamical encounters, form binaries, and potentially merge again. Using a grid of 96 dynamical models of dense star clusters and a cosmological model of cluster formation, we explore the production of binary black hole mergers where at least one component of the binary was forged in a previous merger. We create four hypothetical universes where every black hole born in the collapse of a massive star has a dimensionless Kerr spin parameter, ${\ensuremath{\chi}}_{\text{birth}}$, of 0.0, 0.1, 0.2, or 0.5. We show that if all stellar-born black holes are nonspinning (${\ensuremath{\chi}}_{\text{birth}}=0.0$), then more than 10% of merging binary black holes from clusters have components formed from previous mergers, accounting for more than 20% of the mergers from globular clusters detectable by LIGO/Virgo. Furthermore, nearly 7% of detectable mergers would have a component…

The stochastic gravitational-wave background is a superposition of sources that are either too weak or too numerous to detect individually. In this study, we present the results from a cross-correlation analysis on data from Advanced LIGO's second observing run (O2), which we combine with the results of the first observing run (O1). We do not find evidence for a stochastic background, so we place upper limits on the normalized energy density in gravitational waves at the 95% credible level of ${\mathrm{\ensuremath{\Omega}}}_{\mathrm{GW}}<6.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ for a frequency-independent (flat) background and ${\mathrm{\ensuremath{\Omega}}}_{\mathrm{GW}}<4.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ at 25 Hz for a background of compact binary coalescences. The upper limit improves over the O1 result by a factor of 2.8. Additionally, we place upper limits on the energy density in an isotropic background of scalar- and vector-polarized gravitational waves, and we discuss the implication of these results for models of compact…

We revisit the constraint on the maximum mass of cold spherical neutron stars coming from the observational results of GW170817. We develop a new framework for the analysis by employing both energy and angular momentum conservation laws as well as solid results of latest numerical-relativity simulations and of neutron stars in equilibrium. The new analysis shows that the maximum mass of cold spherical neutron stars can be only weakly constrained as ${M}_{\mathrm{max}}\ensuremath{\lesssim}2.3\text{ }\text{ }{M}_{\ensuremath{\bigodot}}$. Our present result illustrates that the merger remnant neutron star at the onset of collapse to a black hole is not necessarily rapidly rotating and shows that we have to take into account the angular momentum conservation law to impose the constraint on the maximum mass of neutron stars.

Final results are reported from operation of the PICO-60 ${\mathrm{C}}_{3}{\mathrm{F}}_{8}$ dark matter detector, a bubble chamber filled with 52 kg of ${\mathrm{C}}_{3}{\mathrm{F}}_{8}$ located in the SNOLAB underground laboratory. The chamber was operated at thermodynamic thresholds as low as 1.2 keV without loss of stability. A new blind 1404-kg-day exposure at 2.45 keV threshold was acquired with approximately the same expected total background rate as the previous 1167-kg-day exposure at 3.3 keV. This increased exposure is enabled in part by a new optical tracking analysis to better identify events near detector walls, permitting a larger fiducial volume. These results set the most stringent direct-detection constraint to date on the weakly interacting massive particle (WIMP)-proton spin-dependent cross section at $3.2\ifmmode\times\else\texttimes\fi{}1{0}^{\ensuremath{-}41}\text{ }{\mathrm{cm}}^{2}$ for a 25 GeV WIMP, improving on previous PICO results for 3--5 GeV WIMPs by an order of magnitude.

In this work, the author uses a previously developed numerical technique to formulate and investigate a well defined criterion for measuring general perturbation amplitudes for the collapse of primordial black holes, enabling a consistent derivation of how the threshold of primordial black hole formation depends on the shape of the initial density perturbation.

We study the gravitational-wave (GW) signatures of clouds of ultralight bosons around black holes (BHs) in binary inspirals.These clouds, which are formed via superradiance instabilities for rapidly rotating BHs, produce distinct effects in the population of BH masses and spins, and a continuous monochromatic GW signal.We show that the presence of a binary companion greatly enriches the dynamical evolution of the system, most remarkably through the existence of resonant transitions between the growing and decaying modes of the cloud (analogous to Rabi oscillations in atomic physics).These resonances have rich phenomenological implications for current and future GW detectors.Notably, the amplitude of the GW signal from the clouds may be reduced, and in many cases terminated, much before the binary merger.The presence of a boson cloud can also be revealed in the GW signal from the binary through the imprint of finite-size effects, such as spin-induced multipole moments and tidal Love numbers.The time dependence of the cloud's energy density during the resonance leads to a sharp…

Numerical relativity (NR) simulations provide the most accurate binary black hole gravitational waveforms, but are prohibitively expensive for applications such as parameter estimation. Surrogate models of NR waveforms have been shown to be both fast and accurate. However, NR-based surrogate models are limited by the training waveforms' length, which is typically about 20 orbits before merger. We remedy this by hybridizing the NR waveforms using both post-Newtonian and effective one-body waveforms for the early inspiral. We present NRHybSur3dq8, a surrogate model for hybridized nonprecessing numerical relativity waveforms, that is valid for the entire LIGO band (starting at 20 Hz) for stellar mass binaries with total masses as low as $2.25\text{ }\text{ }{M}_{\ensuremath{\bigodot}}$. We include the $\ensuremath{\ell}\ensuremath{\le}4$ and (5, 5) spin-weighted spherical harmonic modes but not the (4, 1) or (4, 0) modes. This model has been trained against hybridized waveforms based on 104 NR waveforms with mass ratios $q\ensuremath{\le}8$, and…

We discuss the ability of a dark fluid becoming relevant around the time of matter-radiation equality to significantly relieve the tension between local measurements of the Hubble constant and cosmic microwave background (CMB) inference, within the $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model. We show that the gravitational impact of acoustic oscillations in the dark fluid balance the effects on the CMB and result in an improved fit to CMB measurements themselves while simultaneously raising the Hubble constant. The required balance favors a model where the fluid is a scalar field that converts its potential to kinetic energy around matter-radiation equality, which then quickly redshifts away. We derive the requirements on the potential for this conversion mechanism and find that a simple canonical scalar with two free parameters for its local slope and amplitude robustly improves the fit to the combined data by $\mathrm{\ensuremath{\Delta}}{\ensuremath{\chi}}^{2}\ensuremath{\approx}12.7$ over $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$. We uncover the CMB polarization…

In this study, we found a new traversable wormhole solution in the framework of a bumblebee gravity model. With these types of models, the Lorentz symmetry violation arises from the dynamics of a bumblebee vector field that is nonminimally coupled with gravity. To this end, we checked the wormhole's flare-out and energy (null, weak, and strong) conditions. We then studied the deflection angle of light in the weak limit approximation using the Gibbons-Werner method. In particular, we show that the bumblebee gravity effect leads to a nontrivial global topology of the wormhole spacetime. By using the Gauss-Bonnet theorem (GBT), it is shown that the obtained non-asymptotically flat wormhole solution yields a topological term in the deflection angle of light. This term is proportional to the coupling constant, but independent from the impact factor parameter. Significantly, we showed that the bumblebee wormhole solutions, under specific conditions, support the normal matter wormhole geometries.

Accurate and fast gravitational waveform (GW) models are essential to extract information about the properties of compact binary systems that generate GWs. Building on previous work, we present an extension of the NRTidal model for binary neutron star (BNS) waveforms. The upgrades are (i) a new closed-form expression for the tidal contribution to the GW phase which includes further analytical knowledge and is calibrated to more accurate numerical relativity data than previously available; (ii) a tidal correction to the GW amplitude; and (iii) an extension of the spin-sector incorporating equation-of-state-dependent finite size effects at quadrupolar and octupolar order; these appear in the spin-spin tail terms and cubic-in-spin terms, both at 3.5 PN. We add the new description to the precessing binary black hole waveform model IMRPhenomPv2 to obtain a frequency-domain precessing binary neutron star model. In addition, we extend the SEOBNRv4_ROM and IMRPhenomD aligned-spin binary black hole waveform models with the improved tidal phase corrections. Focusing on the new…

The EDELWEISS Collaboration has performed a search for dark matter particles with masses below the GeV scale with a 33.4-g germanium cryogenic detector operated in a surface lab. The energy deposits were measured using a neutron-transmutation-doped Ge thermal sensor with a 17.7 eV (rms) baseline heat energy resolution leading to a 60 eV analysis energy threshold. Despite a moderate lead shielding and the high-background environment, the first sub-GeV spin-independent dark matter limit based on a germanium target has been achieved. The experiment provides the most stringent, nuclear-recoil-based, above-ground limit on spin-independent interactions above $600\text{ }\mathrm{MeV}/{\mathrm{c}}^{2}$. The experiment also provides the most stringent limits on spin-dependent interactions with protons and neutrons below $1.3\text{ }\mathrm{GeV}/{\mathrm{c}}^{2}$. Furthermore, the dark matter search results were studied in the context of strongly interacting massive particles, taking into account Earth-shielding effects, for which new regions of the available parameter space have been…

The success of present and future cosmological studies is tied to the ability to detect discrepancies in complex data sets within the framework of a cosmological model. Tensions caused by the presence of unknown systematic effects need to be isolated and corrected to increase the overall accuracy of parameter constraints, while discrepancies due to new physical phenomena need to be promptly identified. We develop a full set of estimators of internal and mutual agreement and disagreement, whose strengths complement each other. These estimators take into account the effect of prior information and compute the statistical significance of both tensions and confirmatory biases. The estimators that we present optimally weight all parameter space directions that are either fully constrained by the data or the prior, allowing for complete and fair degree of freedom counting. We apply them to a wide range of state-of-the-art cosmological probes and show that these estimators can be easily used, regardless of model and data complexity. We derive a series of results that show that…

On 26 March 2019, at the Rencontres de Moriond QCD conference, the LHCb Collaboration reported the observation of three new pentaquarks, namely ${P}_{c}(4312)$, ${P}_{c}(4440)$, and ${P}_{c}(4457)$, which are consistent with the loosely bound molecular hidden-charm pentaquark states composed of an $S$-wave charmed baryon ${\mathrm{\ensuremath{\Sigma}}}_{c}$ and an $S$-wave anticharmed meson ($\overline{D}$, ${\overline{D}}^{*}$). In this work, we present a direct calculation by the one-boson-exchange model and demonstrate explicitly that the ${P}_{c}(4312)$, ${P}_{c}(4440)$, and ${P}_{c}(4457)$ do correspond to the loosely bound ${\mathrm{\ensuremath{\Sigma}}}_{c}\overline{D}$ with ($I=1/2$, ${J}^{P}=1/{2}^{\ensuremath{-}}$), ${\mathrm{\ensuremath{\Sigma}}}_{c}{\overline{D}}^{*}$ with ($I=1/2$, ${J}^{P}=1/{2}^{\ensuremath{-}}$), and ${\mathrm{\ensuremath{\Sigma}}}_{c}{\overline{D}}^{*}$ with ($I=1/2$, ${J}^{P}=3/{2}^{\ensuremath{-}}$), respectively.

The proposed LDMX experiment would provide roughly a meter-long region of instrumented tracking and calorimetry that acts as a beam stop for multi-GeV electrons in which each electron is tagged and its evolution measured. This would offer an unprecedented opportunity to access both collider-invisible and ultrashort-lifetime decays of new particles produced in electron (or muon) nuclear fixed-target collisions. In this paper, we show that the missing momentum channel and displaced decay signals in such an experiment could provide world-leading sensitivity to sub-GeV dark matter, millicharged particles, and visibly or invisibly decaying axions, scalars, dark photons, and a range of other new physics scenarios.

Compared to primordial perturbations on large scales, roughly larger than 1 Mpc, those on smaller scales are not severely constrained. We revisit the issue of probing small-scale primordial perturbations using gravitational waves (GWs), based on the fact that, when large-amplitude primordial perturbations on small scales exist, GWs with relatively large amplitudes are induced at second order in scalar perturbations, and these induced GWs can be probed by both existing and planned gravitational-wave projects. We use accurate methods to calculate these induced GWs and take into account sensitivities of different experiments to induced GWs carefully, to report existing and expected limits on the small-scale primordial spectrum.

Galaxy intrinsic alignments (IA) are a critical uncertainty for current and future weak lensing measurements. We describe a perturbative expansion of IA, analogous to the treatment of galaxy biasing. From an astrophysical perspective, this model includes the expected large-scale alignment mechanisms for galaxies that are pressure-supported (tidal alignment) and rotation-supported (tidal torquing) as well as the cross-correlation between the two. Alternatively, this expansion can be viewed as an effective model capturing all relevant effects up to the given order. We include terms up to second order in the density and tidal fields and calculate the resulting IA contributions to two-point statistics at one-loop order. For fiducial amplitudes of the IA parameters, we find the quadratic alignment and linear-quadratic cross terms can contribute order-unity corrections to the total intrinsic alignment signal at $k\ensuremath{\sim}0.1\text{ }\text{ }{h}^{\ensuremath{-}1}\text{ }\mathrm{Mpc}$, depending on the source redshift distribution. These contributions can lead to significant biases…

A Markov chain update scheme using a machine-learned flow-based generative model is proposed for Monte Carlo sampling in lattice field theories. The generative model may be optimized (trained) to produce samples from a distribution approximating the desired Boltzmann distribution determined by the lattice action of the theory being studied. Training the model systematically improves autocorrelation times in the Markov chain, even in regions of parameter space where standard Markov chain Monte Carlo algorithms exhibit critical slowing down in producing decorrelated updates. Moreover, the model may be trained without existing samples from the desired distribution. The algorithm is compared with HMC and local Metropolis sampling for ${\ensuremath{\phi}}^{4}$ theory in two dimensions.

The properties of compact binaries, such as masses and spins, are imprinted in the gravitational waves (GWs) they emit and can be measured using parametrized waveform models. Accurately and efficiently describing the complicated precessional dynamics of the various angular momenta of the system in these waveform models is the object of active investigation. One of the key models extensively used in the analysis of LIGO and Virgo data is the single-precessing-spin waveform model IMRPhenomPv2. In this article we present a new model IMRPhenomPv3, which includes the effects of two independent spins in the precession dynamics. Whereas IMRPhenomPv2 utilizes a single-spin frequency-dependent post-Newtonian rotation to describe precession effects, the improved model, IMRPhenomPv3, employs a double-spin rotation that is based on recent developments in the description of precessional dynamics. Besides double-spin precession, the improved model benefits from a more accurate description of precessional effects. We validate our new model against a large set of precessing numerical-relativity…

The presence of dark matter around a black hole remarkably affects its spacetime. We consider the effects of dark matter on the shadow of a new solution to the Einstein equations that describes a rotating black hole in the background of perfect dark matter fluid, along with its extension to nonzero cosmological constant $\mathrm{\ensuremath{\Lambda}}$. Working in Boyer-Lindquist coordinates, we consider the effects of the perfect dark matter fluid parameter $\ensuremath{\alpha}$ on the shadow cast by a black hole with respect to an observer at position $({r}_{o},{\ensuremath{\theta}}_{o})$. By applying the Gauss-Bonnet theorem to the optical geometry, we find that notable distortions from a Kerr black hole can occur. We describe their dependence on $\ensuremath{\alpha}$ and $\mathrm{\ensuremath{\Lambda}}$.

The idea that primordial black holes (PBHs) can comprise most of the dark matter of the Universe has recently reacquired a lot of momentum. Observational constraints, however, rule out this possibility for most of the PBH masses, with a notable exception around ${10}^{\ensuremath{-}12}\text{ }\text{ }{M}_{\ensuremath{\bigodot}}$. These light PBHs may be originated when a sizable comoving curvature perturbation generated during inflation reenters the horizon during the radiation phase. During such a stage, it is unavoidable that gravitational waves (GWs) are generated. Since their source is quadratic in the curvature perturbations, these GWs are generated fully non-Gaussian. Their frequency today is about a millihertz, which is exactly the range where the LISA mission has the maximum of its sensitivity. This is certainly an impressive coincidence. We show that this scenario of PBHs as dark matter can be tested by LISA by measuring the GW two-point correlator. On the other hand, we show that the short observation time (as compared to the age of the Universe) and propagation effects of…

The combined observation of gravitational and electromagnetic waves from the coalescence of two neutron stars marks the beginning of multimessenger astronomy with gravitational waves (GWs). The development of accurate gravitational waveform models is a crucial prerequisite to extract information about the properties of the binary system that generated a detected GW signal. In binary neutron star systems (BNS), tidal effects also need to be incorporated in the modeling for an accurate waveform representation. Building on previous work [Phys. Rev. D 96, 121501 (2017)], we explore the performance of inspiral-merger waveform models that are obtained by adding a numerical relativity (NR) based approximant for the tidal part of the phasing ($\mathrm{NRTidal}$) to existing models for nonprecessing and precessing binary black hole systems, as implemented in the LSC Algorithm Library Suite. The resulting BNS waveforms are compared and contrasted to a set of target waveforms which we obtain by hybridizing NR waveforms (covering the last $\ensuremath{\sim}10$ orbits up to the merger and…

We study the link between classical scattering of spinning black holes and quantum amplitudes for massive spin-$s$ particles. Generic spin orientations of the black holes are considered, allowing their spins to be deflected on par with their momenta. We rederive the spin-exponentiated structure of the relevant tree-level amplitude from minimal coupling to Einstein's gravity, which in the $s\ensuremath{\rightarrow}\ensuremath{\infty}$ limit generates the black holes' complete series of spin-induced multipoles. The resulting scattering function is seen to encode in a simple way the known net changes in the black-hole momenta and spins at first post-Minkowskian order. We connect our findings to a rigorous framework developed elsewhere for computing such observables from amplitudes.

We investigate interacting scenarios that belong to a wider class, since they include a dynamical dark energy component whose equation of state follows various one-parameter parametrizations. We confront them with the latest observational data from the cosmic microwave background, the joint light-curve sample from type Ia supernovae, baryon acoustic oscillations, Hubble parameter measurements from cosmic chronometers (CC), and a Gaussian prior on the Hubble parameter ${H}_{0}$. In all examined scenarios we find a nonzero interaction; nevertheless, the noninteracting case is allowed within $2\ensuremath{\sigma}$. Concerning the current value of the dark energy equation of state for all combinations of data sets, it always lies in the phantom regime at more than 2--3 standard deviations. Finally, for all interacting models, independently of the combination of data sets considered, the estimated values of the present Hubble parameter ${H}_{0}$ are greater compared to the $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$-based Planck estimate and close to the local measurements, thus…

Despite growing interest and extensive effort to search for ultralight dark matter in the form of a hypothetical dark photon, how it fits into a consistent cosmology is unclear. Several dark photon dark matter production mechanisms proposed previously are known to have limitations, at least in certain mass regimes of experimental interest. In this paper, we explore a novel mechanism, where a coherently oscillating axionlike field can efficiently transfer its energy density to a dark photon field via a tachyonic instability. The residual axion relic is subsequently depleted via couplings to the visible sector, leaving only the dark photon as dark matter. We ensure that the cosmologies of both the axion and dark photon are consistent with existing constraints. We find that the mechanism works for a broad range of dark photon masses, including those of interest for ongoing experiments and proposed detection techniques.

Predicting signals in experiments to directly detect dark matter (DM) requires a form for the local DM velocity distribution. Hitherto, the standard halo model (SHM), in which velocities are isotropic and follow a truncated Gaussian law, has performed this job. New data, however, suggest that a substantial fraction of our stellar halo lies in a strongly radially anisotropic population, the ``Gaia sausage.'' Inspired by this recent discovery, we introduce an updated DM halo model, the ${\mathrm{SHM}}^{++}$, which includes a ``sausage'' component, thus better describing the known features of our Galaxy. The ${\mathrm{SHM}}^{++}$ is a simple analytic model with five parameters: the circular speed, local escape speed, and local DM density, which we update to be consistent with the latest data, and two new parameters: the anisotropy and the density of DM in the sausage. The impact of the ${\mathrm{SHM}}^{++}$ on signal models for weakly interacting massive particles (WIMPs) and axions is rather modest since the multiple changes and updates have competing effects. In particular, this…

The universal radiative corrections common to neutron and superallowed nuclear beta decays (also known as ``inner'' corrections) are revisited in light of a recent dispersion relation study that found $+2.467(22)%$, i.e., about $2.4\ensuremath{\sigma}$ larger than the previous evaluation. For comparison, we consider several alternative computational methods. All employ an updated perturbative QCD four-loop Bjorken sum rule defined QCD coupling supplemented with a nucleon form factor based Born amplitude to estimate axial-vector induced hadronic contributions. In addition, we now include hadronic contributions from low ${Q}^{2}$ loop effects based on duality considerations and vector meson resonance interpolators. Our primary result, 2.426(32)%, corresponds to an average of a light-front holographic QCD approach and a three-resonance interpolator fit. It reduces the dispersion relation discrepancy to approximately $1.1\ensuremath{\sigma}$ and thereby provides a consistency check. Consequences of our new radiative correction estimate, along with that of the dispersion relation result,…

The LIGO Scientific Collaboration has generously made the data from its First Observing Run (O1) publicly available, including that from the two history-making observations of gravitational waves from binary black hole merger events GW150914 and GW151226. In this paper, the authors apply an independent search pipeline to the aLIGO O1 data to search for additional gravitational wave events and argue for the existence of a previously undiscovered BH merger event, GW151216.

We calculate the Wigner function for massive $\mathrm{spin}\text{\ensuremath{-}}1/2$ particles in an inhomogeneous electromagnetic field to leading order in the Planck constant $\ensuremath{\hbar}$. Going beyond leading order in $\ensuremath{\hbar}$ we then derive a generalized Boltzmann equation in which the force exerted by an inhomogeneous electromagnetic field on the particle dipole moment arises naturally. Furthermore, a kinetic equation for this dipole moment is derived. Carefully taking the massless limit we find agreement with previous results. The case of global equilibrium with rotation is also studied. Finally, we outline the derivation of fluid-dynamical equations from the components of the Wigner function. The conservation of total angular momentum is promoted as an additional fluid-dynamical equation of motion. Our framework can be used to study polarization effects induced by vorticity and magnetic field in relativistic heavy-ion collisions.

We develop a nonparametric method for inferring the universal neutron star (NS) equation of state (EOS) from gravitational wave (GW) observations. Many different possible realizations of the EOS are generated with a Gaussian process conditioned on a set of nuclear-theoretic models. These synthetic EOSs are causal and thermodynamically stable by construction, span a broad region of the pressure-density plane, and can be selected to satisfy astrophysical constraints on the NS mass. Associating every synthetic EOS with a pair of component masses ${M}_{1,2}$ and calculating the corresponding tidal deformabilities ${\mathrm{\ensuremath{\Lambda}}}_{1,2}$, we perform Monte Carlo integration over the GW likelihood for ${M}_{1,2}$ and ${\mathrm{\ensuremath{\Lambda}}}_{1,2}$ to directly infer a posterior process for the NS EOS. We first demonstrate that the method can accurately recover the properties of an injected GW signal, and subsequently use it to analyze data from GW170817, finding a canonical deformability of ${\mathrm{\ensuremath{\Lambda}}}_{1.4}=16{0}_{\ensuremath{-}113}^{+448}$ and…

The simplest extension of the standard model consists in adding one singlet scalar field which mixes with the Higgs boson. $\mathcal{O}(\mathrm{GeV})$ masses of the new scalar carry strong motivation from relaxion, dark matter and inflation models. The decay of a GeV scalar is, however, notoriously difficult to address since, at this mass scale, the chiral expansion breaks down and perturbative QCD does not apply. Existing estimates of the GeV scalar decay rate disagree by several orders of magnitude. In this work, we perform a new dispersive analysis in order to strongly reduce these uncertainties and to address discrepancies in earlier results. We will update existing limits on light scalars and future experimental sensitivities which are in some cases strongly affected by the new-found decay rates. The meson form factors provided in this work, can be used to generalize our findings to non-universally coupled light scalars.

We propose using neural networks to detect data departures from a given reference model, with no prior bias on the nature of the new physics responsible for the discrepancy. The virtues of neural networks as unbiased function approximants make them particularly suited for this task. An algorithm that implements this idea is constructed, as a straightforward application of the likelihood-ratio hypothesis test. The algorithm compares observations with an auxiliary set of reference-distributed events, possibly obtained with a Monte Carlo event generator. It returns a $p$ value, which measures the compatibility of the reference model with the data. It also identifies the most discrepant phase-space region of the data set, to be selected for further investigation. The most interesting potential applications are model-independent new physics searches, although our approach could also be used to compare the theoretical predictions of different Monte Carlo event generators, or for data validation algorithms. In this work we study the performance of our algorithm on a few simple examples.…

Effective theory arguments are used to derive the most general energy-momentum tensor of a relativistic viscous fluid with an arbitrary equation of state (in the absence of other conserved currents) that is first-order in the derivatives of the energy density and flow velocity and does not include extended variables such as in Mueller-Israel-Stewart-like theories. This energy-momentum tensor leads to a causal theory, provided one abandons the usual conventions for the out-of-equilibrium hydrodynamic variables put forward by Landau-Lifshitz and Eckart. In particular, causality requires nonzero out-of-equilibrium energy density corrections and heat flow. Conditions are found to ensure linear stability around equilibrium in flat space-time. We also prove local existence and uniqueness of solutions to the equations of motion. Our causality, existence, and uniqueness results hold in the full nonlinear regime, without symmetry assumptions, in four space-time dimensions, with or without coupling to Einstein's equations, and are mathematically rigorously established. Furthermore, a kinetic…

We present the results of a lattice calculation of tetraquark states with quark contents ${q}_{1}{q}_{2}\overline{Q}\overline{Q},{q}_{1},{q}_{2}\ensuremath{\subset}u,d,s,c$ and $Q\ensuremath{\equiv}b$, $c$ in both spin-0 ($J=0$) and spin-1 ($J=1$) sectors. This calculation is performed on three dynamical ${N}_{f}=2+1+1$ highly improved staggered quark ensembles at lattice spacings of about 0.12, 0.09, and 0.06 fm. We use the overlap action for light to charm quarks, while a nonrelativistic action with nonperturbatively improved coefficients with terms up to $\mathcal{O}({\ensuremath{\alpha}}_{s}{v}^{4})$ is employed for the bottom quark. While considering charm or bottom quarks as heavy, we calculate the energy levels of various four-quark configurations with light quark masses ranging from the physical strange quark mass to that of the corresponding physical pion mass. This enables us to explore the quark mass dependence of the extracted four-quark energy levels over a wide range of quark masses. The results of the spin-1 states show the presence of ground state energy levels which…

In this paper we present a new black hole solution surrounded by dark matter (DM) halo in the galactic center using the mass model of M87 and that coming from the universal rotation curve (URC) dark matter profile representing family of spiral galaxies. In both cases the DM halo density is cored with a size ${r}_{0}$ and a central density ${\ensuremath{\rho}}_{0}$: $\ensuremath{\rho}(r)={\ensuremath{\rho}}_{0}/(1+r/{r}_{0})(1+(r/{r}_{0}{)}^{2})$. Since ${r}_{0}{\ensuremath{\rho}}_{0}=120\text{ }\text{ }{\mathrm{M}}_{\ensuremath{\bigodot}}/{\mathrm{pc}}^{2}$ [Mon. Not. R. Astron. Soc. 397, 1169 (2009)], then by varying the central density one can reproduce the DM profile in any spiral. Using the Newman-Jains method we extend our solution to obtain a rotating black hole surrounded by dark matter halo. We find that the apparent shape of the shadow beside the black hole spin $a$, it also depends on the central density of the surrounded dark matter ${\ensuremath{\rho}}_{0}$. As a specific example we consider the galaxy M87, with a central density…

One of the most intriguing current puzzles in cosmology is the discrepancy in the present values of the Hubble constant ${H}_{0}$, obtained either from direct model-independent distance measurements or from the CMB, i.e. its value about 13 billion years ago and interpreted through the standard model of cosmology ($\mathrm{\ensuremath{\Lambda}}\phantom{\rule{0}{0ex}}C\phantom{\rule{0}{0ex}}D\phantom{\rule{0}{0ex}}M$). The authors outline a scenario based on dark matter decays in the late time Universe, which is potentially testable with near future surveys, that can eliminate this discrepancy.

Vector bosons heavier than ${10}^{\ensuremath{-}22}\text{ }\text{ }\mathrm{eV}$ can be viable dark matter candidates with distinctive experimental signatures. Ultralight dark matter generally requires a nonthermal origin to achieve the observed density, while still behaving like a pressureless fluid at late times. We show that such a production mechanism naturally occurs for vectors whose mass originates from a dark Higgs. If the dark Higgs has a large field value after inflation, the energy in the Higgs field can be efficiently transferred to vectors through parametric resonance. Computing the resulting abundance and spectra requires careful treatment of the transverse and longitudinal components, whose dynamics are governed by distinct equations of motion. We study these in detail and find that the mass of the vector may be as low as ${10}^{\ensuremath{-}18}\text{ }\text{ }\mathrm{eV}$, while making up the majority of the dark matter abundance. This opens up a wide mass range of vector dark matter as cosmologically viable, and further motivates the experimental searches for such…

The detection of the least damped quasinormal mode from the remnant of the gravitational wave event GW150914 realized the long-sought possibility of observationally studying the properties of quasistationary black hole spacetimes through gravitational waves. Past literature has extensively explored this possibility, and the emerging field has been named ``black hole spectroscopy.'' In this study, we present results regarding the ringdown spectrum of GW150914, obtained by application of Bayesian inference to identify and characterize the ringdown modes. We employ a pure time-domain analysis method, which infers from the data the time of transition between the nonlinear and quasilinear regimes of the postmerger emission in concert with all other parameters characterizing the source. We find that the data provide no evidence for the presence of more than one quasinormal mode. However, from the central frequency and damping time posteriors alone, no unambiguous identification of a single mode is possible. More in-depth analysis adopting a ringdown model based on results in perturbation…

We calculate logarithmic negativity, a quantum entanglement measure for mixed quantum states, in quantum error-correcting codes and find it to equal the minimal cross sectional area of the entanglement wedge in holographic codes with a quantum correction term equal to the logarithmic negativity between the bulk degrees of freedom on either side of the entanglement wedge cross section. This leads us to conjecture a holographic dual for logarithmic negativity that is related to the area of a cosmic brane with tension in the entanglement wedge plus a quantum correction term. This is closely related to (though distinct from) the holographic proposal for entanglement of purification. We check this relation for various configurations of subregions in ${\mathrm{AdS}}_{3}/{\mathrm{CFT}}_{2}$. These are disjoint intervals at zero temperature, as well as a single interval and adjacent intervals at finite temperature. We also find this prescription to effectively characterize the thermofield double state. We discuss how a deformation of a spherical entangling region complicates calculations…

We study the nonlinear dynamics of black holes that carry scalar hair and binaries composed of such black holes. The scalar hair is due to a linear or exponential coupling between the scalar and the Gauss-Bonnet invariant. We work perturbatively in the coupling constant of that interaction but nonperturbatively in the fields. We first consider the dynamical formation of hair for isolated black holes of arbitrary spin and determine the final state. This also allows us to compute for the first time the scalar quasinormal modes of rotating black holes in the presence of this coupling. We then study the evolution of nonspinning black hole binaries with various mass ratios and produce the first scalar waveform for a coalescence. An estimate of the energy loss in scalar radiation and the effect this has on orbital dynamics and the phase of gravitational waves (GWs) (entering at quadratic order in the coupling) shows that GW detections can set the most stringent constraint to date on theories that exhibit a coupling between a scalar field and the Gauss-Bonnet invariant.

The oldest and most robust technique to search for new particles is to look for ``bumps'' in invariant mass spectra over smoothly falling backgrounds. We present a new extension of the bump hunt that naturally benefits from modern machine learning algorithms while remaining model agnostic. This approach is based on the classification without labels (CWoLa) method where the invariant mass is used to create two potentially mixed samples, one with little or no signal and one with a potential resonance. Additional features that are uncorrelated with the invariant mass can be used for training the classifier. Given the lack of new physics signals at the Large Hadron Collider (LHC), such model-agnostic approaches are critical for ensuring full coverage to fully exploit the rich datasets from the LHC experiments. In addition to illustrating how the new method works in simple test cases, we demonstrate the power of the extended bump hunt on a realistic all-hadronic resonance search in a channel that would not be covered with existing techniques.

The present work is focused on the investigation of the existence of compact structures describing anisotropic matter distributions within the framework of modified gravity theories, specifically $f(R,\mathcal{T}$) gravity theory. Additionally, we have taken $f(R,\mathcal{T})$ as a linear function of the Ricci scalar $R$ and the trace of the energy-momentum tensor $\mathcal{T}$ as $f(R,\mathcal{T})=R+2\ensuremath{\chi}\mathcal{T}$, where $\ensuremath{\chi}$ is a dimensionless coupling parameter, and the Lagrangian matter ${\mathcal{L}}_{m}=\ensuremath{-}\frac{1}{3}(2{p}_{t}+{p}_{r})$, to describe the complete set of field equations for the anisotropic matter distribution. We follow the embedding class I procedure using the Eisland condition to obtain a full space-time description inside the stellar configuration. Once the space-time geometry is specified, we determine the complete solution of modified Einstein equations by using the MIT bag model equation of state ${p}_{r}=\frac{1}{3}(\ensuremath{\rho}\ensuremath{-}4B)$ that describes the strange quark matter (SQM) distribution…

In this paper, we report on the construction of a new and independent pipeline for analyzing the public data from the first observing run of Advanced LIGO for mergers of compact binary systems. The pipeline incorporates different techniques and makes independent implementation choices in all its stages including the search design, the method to construct template banks, the automatic routines to detect bad data segments (``glitches'') and to insulate good data from them, the procedure to account for the nonstationary nature of the detector noise, the signal-quality vetoes at the single-detector level and the methods to combine results from multiple detectors. Our pipeline enabled us to identify a new binary black hole merger GW151216 in the public LIGO data. This paper serves as a bird's eye view of the pipeline's important stages. Full details and derivations underlying the various stages will appear in accompanying papers.

We study the concept of Carrollian spacetime starting from its underlying fiber-bundle structure. The latter admits an Ehresmann connection, which enables a natural separation of time and space, preserved by the subset of Carrollian diffeomorphisms. These allow for the definition of Carrollian tensors and the structure at hand provides the designated tools for describing the geometry of null hypersurfaces embedded in Lorentzian manifolds. Using these tools, we investigate the conformal isometries of general Carrollian spacetimes and their relationship with the BMS group.

The 2017 detection of the inspiral and merger of two neutron stars in gravitational waves and gamma rays was accompanied by a quickly reddening transient. Such a transient was predicted to occur following a rapid neutron capture (r-process) nucleosynthesis event, which synthesizes neutron-rich, radioactive nuclei and can take place in both dynamical ejecta and in the wind driven off the accretion torus formed after a neutron star merger. We present the first three-dimensional general relativistic, full transport neutrino radiation magnetohydrodynamics simulations of the black hole-accretion disk-wind system produced by the GW170817 merger. We show that the small but non-negligible optical depths lead to neutrino transport globally coupling the disk electron fraction, which we capture by solving the transport equation with a Monte Carlo method. The resulting absorption drives up the electron fraction in a structured, continuous outflow, with electron fraction as high as ${Y}_{e}\ensuremath{\sim}0.4$ in the extreme polar region. We show via nuclear reaction network and radiative…

We describe the computation of post-Minkowskian Hamiltonians in general relativity from scattering amplitudes. Using a relativistic Lippmann-Schwinger equation, we relate perturbative amplitudes of massive scalars coupled to gravity to the post-Minkowskian Hamiltonians of classical general relativity to any order in Newton's constant. We illustrate this by deriving a Hamiltonian for binary black holes without spin up to second order in the post-Minkowskian expansion and explicitly demonstrate the equivalence with the recently proposed method based on an effective field theory matching.

Gravitational wave (GW) measurements will provide insight into the population of coalescing compact binaries throughout the universe. We describe and demonstrate a flexible parametric method to infer the event rate as a function of compact binary parameters, accounting for Poisson error and selection biases. Using synthetic data based on projections for LIGO and Virgo's third observing run (O3), we discuss how well GW measurements could constrain the mass and spin distribution of coalescing neutron stars and black holes (BHs) in the near future, within the context of several phenomenological models described in this work. We demonstrate that only a few tens of events can enable astrophysically significant constraints on the spin magnitude and orientation distribution of BHs in merging binaries. We discuss how astrophysical priors or other measurements can inform the interpretation of future measurements. Using publicly available results, we estimate the event rate versus mass for binary black holes (BBHs). To connect to previously published work, we provide estimates including…

In this article we present a class of relativistic solutions describing spherically symmetric and static anisotropic stars in hydrostatic equilibrium. For this purpose, we consider a particularized metric potential, namely, Buchdahl ansatz [Phys. Rev. D 116, 1027 (1959).] which encompasses almost all the known analytic solutions to the spherically symmetric, static Einstein equations with a perfect fluid source, including, in particular, the Vaidya-Tikekar and Finch-Skea. We developed the model by considering an anisotropic spherically symmetric static general relativistic configuration that has a significant effect on the structure and properties of stellar objects. We have considered eight different cases for generalized Buchdahl dimensionless parameter $K$ and analyzed them in a uniform manner. As a result it turns out that all the considered cases are valid at every point in the interior spacetime. In addition to this, we show that the model satisfies all the energy conditions and maintains the hydrostatic equilibrium equation. In the frame work of anisotropic hypothesis, we…

Although cosmic microwave background and large scale structure probe the largest scales of our Universe with ever-increasing precision, our knowledge about the smaller scales is still very limited other than the bounds on primordial black holes (PBHs). We show that the statistical properties of the small scale quantum fluctuations can be probed via the stochastic gravitational wave (GW) background, which is induced as the scalar modes reenter the horizon. We found that even if scalar curvature fluctuations have a subdominant non-Gaussian component, these non-Gaussian perturbations can source a dominant portion of the induced GWs. Moreover, the GWs sourced by non-Gaussian scalar fluctuations peak at a higher frequency and this can result in distinctive observational signatures. If the induced GW background is detected, but not the signatures arising from the non-Gaussian component, $\ensuremath{\zeta}={\ensuremath{\zeta}}_{G}+{f}_{\mathrm{NL}}{\ensuremath{\zeta}}_{G}^{2}$, this translates into bounds on ${f}_{\mathrm{NL}}$ depending on the amplitude and the width of the GW signal.…

If a phase transition is allowed to take place in the core of a compact star, a new stable branch of equilibrium configurations can appear, providing solutions with the same mass as the purely hadronic branch and hence giving rise to ``twin-star'' configurations. We perform an extensive analysis of the features of the phase transition leading to twin-star configurations and, at the same time, fulfilling the constraints coming from the maximum mass of $2\text{ }\text{ }{M}_{\ensuremath{\bigodot}}$ and the information following gravitational-wave event GW170817. In particular, we use a general equation of state for the neutron-star matter that parametrizes the hadron-quark phase transition between the model describing the hadronic phase and a constant speed of sound for the quark phase. We find that the largest number of twin-star solutions has masses in the neutron-star branch that are in the range $1--2\text{ }\text{ }{M}_{\ensuremath{\bigodot}}$ and maximum masses $\ensuremath{\gtrsim}2\text{ }\text{ }{M}_{\ensuremath{\bigodot}}$ in the twin-star branch. The analysis of the masses,…

Cold dark matter (CDM) could be composed of primordial black holes (PBH) in addition to or instead of more orthodox weakly interacting massive particle dark matter (PDM). We study the formation of the first structures in such $\mathrm{\ensuremath{\Lambda}}\mathrm{PBH}$ cosmologies using $N$-body simulations evolved from deep in the radiation era to redshift 99. When PBH are only a small component of the CDM, they are clothed by PDM to form isolated halos. On the other hand, when PBH make most of the CDM, halos can also grow via clustering of many PBH. We find that the halo mass function is well modelled via Poisson statistics assuming random initial conditions. We quantify the nonlinear velocities induced by structure formation and find that they are too small to significantly impact CMB constraints. A chief challenge is how best to extrapolate our results to lower redshifts relevant for some observational constraints.

We consider the ${\overline{D}}^{(*)}{\mathrm{\ensuremath{\Sigma}}}_{c}^{(*)}$ states, together with $J/\ensuremath{\psi}N$ and other coupled channels, and take an interaction consistent with heavy quark spin symmetry, with the dynamical input obtained from an extension of the local hidden gauge approach. By fitting only one parameter to the recent three pentaquark states reported by the LHCb Collaboration, we can reproduce the three of them in base to the mass and the width, providing for them the quantum numbers and approximate molecular structure as $1/{2}^{\ensuremath{-}}$ $\overline{D}{\mathrm{\ensuremath{\Sigma}}}_{c}$, $1/{2}^{\ensuremath{-}}$ ${\overline{D}}^{*}{\mathrm{\ensuremath{\Sigma}}}_{c}$, and $3/{2}^{\ensuremath{-}}$ ${\overline{D}}^{*}{\mathrm{\ensuremath{\Sigma}}}_{c}$, and the isospin $I=1/2$. We find another state around 4374 MeV, of the $3/{2}^{\ensuremath{-}}$ $\overline{D}{\mathrm{\ensuremath{\Sigma}}}_{c}^{*}$ structure, for which indications appear in the experimental spectrum. Two other near degenerate states of a $1/{2}^{\ensuremath{-}}$…

We propose a novel dispersive treatment of the so-called inner radiative correction to the neutron and nuclear $\ensuremath{\beta}$ decay. We show that it requires knowledge of the parity-violating structure function ${F}_{3}^{(0)}$ that arises from the interference of the axial vector charged current and the isoscalar part of the electromagnetic current. By isospin symmetry, we relate this structure function to the charged current inelastic scattering of neutrinos and antineutrinos. Applying this new data-driven analysis we obtain a new, more precise evaluation for the universal radiative correction ${\mathrm{\ensuremath{\Delta}}}_{R}^{V,\mathrm{new}}=0.02467(22)$ that supersedes the previous estimate by Marciano and Sirlin, ${\mathrm{\ensuremath{\Delta}}}_{R}^{V}=0.02361(38)$. The substantial shift in the central value of ${\mathrm{\ensuremath{\Delta}}}_{R}^{V}$ reflects in a respective shift of ${V}_{ud}$ and a considerable tension in the unitarity constraint on the first row of the Cabibbo-Kobayashi-Maskawa matrix which is used as one of the most stringent constraints on new…

DEAP-3600 is a single-phase liquid argon (LAr) direct-detection dark matter experiment, operating 2 km underground at SNOLAB (Sudbury, Canada). The detector consists of 3279 kg of LAr contained in a spherical acrylic vessel. This paper reports on the analysis of a $758\text{ }\text{ }\mathrm{tonne}\ifmmode\cdot\else\textperiodcentered\fi{}\mathrm{day}$ exposure taken over a period of 231 live-days during the first year of operation. No candidate signal events are observed in the WIMP-search region of interest, which results in the leading limit on the WIMP-nucleon spin-independent cross section on a LAr target of $3.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}45}\text{ }\text{ }{\mathrm{cm}}^{2}$ ($1.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}44}\text{ }\text{ }{\mathrm{cm}}^{2}$) for a $100\text{ }\text{ }\mathrm{GeV}/{\mathrm{c}}^{2}$ ($1\text{ }\text{ }\mathrm{TeV}/{\mathrm{c}}^{2}$) WIMP mass at 90% C.L. In addition to a detailed background model, this analysis demonstrates the best pulse-shape discrimination in LAr at threshold, employs a Bayesian…

The Newman-Janis (NJ) algorithm has been extensively used in the literature to generate rotating black hole solutions from nonrotating seed spacetimes. In this work, we show, using various constants of motion, that the null geodesic equations in an arbitrary stationary and axially symmetric rotating spacetime obtained through the NJ algorithm can be separated completely, provided that the algorithm is applied successfully without any inconsistency. Using the separated null geodesic equations, we then obtain an analytic general formula for obtaining the contour of a shadow cast by a compact object whose gravitational field is given by the arbitrary rotating spacetime under consideration. As special cases, we apply our general analytic formula to some known black holes and reproduce the corresponding results for black hole shadow. Finally, we consider a new example and study shadow using our analytic general formula.

We present the steps to forecast the sensitivity of the Laser Interferometer Space Antenna (LISA) to both a stochastic gravitational wave background and deterministic wave sources. We show how to use these expressions to estimate the precision with which LISA can determine parameters associated with these sources. Tools are included to enable easy calculation of the signal-to-noise ratio and draw sensitivity curves. Benchmark values are given for easy comparison and checking of methods in the case of three worked examples. The first benchmark is the threshold stochastic gravitational wave background ${\mathrm{\ensuremath{\Omega}}}_{\mathrm{GW}}{h}^{2}$ that LISA can observe. The second is the signal-to-noise ratio that LISA would observe for a binary black hole system identical to GW150914, radiating four years before merger. The third is the case of a monotone source, such as a binary that is far from merger.

To account for the dark-matter content in our Universe, postinflationary scenarios predict for the QCD axion a mass in the range $(10--{10}^{3})\text{ }\text{ }\ensuremath{\mu}\mathrm{eV}$. Searches with haloscope experiments in this mass range require the monitoring of resonant cavity modes with frequency above 5 GHz, where several experimental limitations occur due to linear amplifiers, small volumes, and low quality factors of copper resonant cavities. In this paper, we deal with the last issue, presenting the result of a search for galactic axions using a haloscope based on a $36\text{ }\text{ }{\mathrm{cm}}^{3}$ NbTi superconducting cavity. The cavity worked at $T=4\text{ }\text{ }\mathrm{K}$ in a 2 T magnetic field and exhibited a quality factor ${Q}_{0}=4.5\ifmmode\times\else\texttimes\fi{}{10}^{5}$ for the TM010 mode at 9 GHz. With such values of $Q$, the axion signal is significantly increased with respect to copper cavity haloscopes. Operating this setup, we set the limit…

Scalar-tensor theories of gravity where a new scalar degree of freedom couples to the Gauss-Bonnet invariant can exhibit the phenomenon of spontaneous black hole scalarization. These theories admit both the classic black hole solutions predicted by general relativity as well as novel hairy black hole solutions. The stability of hairy black holes is strongly dependent on the precise form of the scalar-gravity coupling. A radial stability investigation revealed that all scalarized black hole solutions are unstable when the coupling between the scalar field and the Gauss-Bonnet invariant is quadratic in the scalar, whereas stable solutions exist for exponential couplings. Here, we elucidate this behavior. We demonstrate that, while the quadratic term controls the onset of the tachyonic instability that gives rise to the black hole hair, the higher-order coupling terms control the nonlinearities that quench that instability and, hence, also control the stability of the hairy black hole solutions.

For a variety of ongoing and planned gravitational-wave (GW) experiments, we study expected constraints on the fraction (${f}_{\mathrm{PBH}}$) of primordial black holes (PBHs) in dark matter by evaluating the energy-density spectra of two kinds of stochastic GW backgrounds. The first one is produced from an incoherent superposition of GWs emitted from coalescences of all of the binary PBHs. The second one is induced through nonlinear mode couplings of large primordial curvature perturbations inevitably associated with the generation of PBHs in the early Universe. In this paper, we focus on PBHs with masses ${10}^{\ensuremath{-}8}\text{ }\text{ }{M}_{\ensuremath{\bigodot}}\ensuremath{\le}{M}_{\mathrm{PBH}}<1\text{ }\text{ }{M}_{\ensuremath{\bigodot}}$, since they are not expected to be of stellar origin. In almost all mass ranges, we show that the experiments are sensitive enough to constrain the fraction for ${10}^{\ensuremath{-}5}\ensuremath{\lesssim}{f}_{\mathrm{PBH}}\ensuremath{\lesssim}1$ by considering the GWs from coalescing events and…

The combined analysis of the BABAR, Belle, and LHCb data on $B\ensuremath{\rightarrow}D\ensuremath{\tau}\ensuremath{\nu}$, $B\ensuremath{\rightarrow}{D}^{*}\ensuremath{\tau}\ensuremath{\nu}$ and ${B}_{c}\ensuremath{\rightarrow}J/\mathrm{\ensuremath{\Psi}}\ensuremath{\tau}\ensuremath{\nu}$ decay observables shows evidence of physics beyond the Standard Model (SM). In this article, we study all the one- and two-dimensional scenarios which can be generated by adding a single new particle to the SM. We put special emphasis on the model-discriminating power of ${F}_{L}({D}^{*})$ and of the $\ensuremath{\tau}$ polarizations, and especially on the constraint from the branching fraction $\mathrm{BR}({B}_{c}\ensuremath{\rightarrow}\ensuremath{\tau}\ensuremath{\nu})$. We critically review this constraint and do not support the aggressive limit of $\mathrm{BR}({B}_{c}\ensuremath{\rightarrow}\ensuremath{\tau}\ensuremath{\nu})<10%$ used in some analyses. While the impact of ${F}_{L}({D}^{*})$ is currently still limited, the…

We discuss the horizon properties, shadow cast, and the weak gravitational lensing of charged rotating regular black holes, which in addition to mass ($M$) and rotation parameter ($a$) have an electric charge ($Q$) and magnetic charge ($g$). The considered regular black holes are the generalization of the Kerr ($Q=g=0$) and Kerr-Newman ($g=0$) black holes. Interestingly, for a given parameter set, the apparent size of the shadow monotonically decreases and the shadow gets more distorted with increasing charge parameter $Q$. We put constraints on the black hole parameters with the aid of recent M87* shadow observation. The conserved quantities associated with the rotating regular black holes are calculated and also a brief description of the weak gravitational lensing using the Gauss-Bonnet theorem is presented. Interestingly, the deflection angle decreases with the charge of the black hole. Our results vis-\`a-vis go over to the Kerr and Kerr-Newman black holes in the appropriate limits.

In this paper, we study the shadow cast by two types of charged and slowly rotating black holes in the Einstein-\AE{}ther theory of gravity. These two types of black holes correspond to two specific combinations of the coupling constants of the \ae{}ther field, i.e., ${c}_{14}=0$ but ${c}_{123}\ensuremath{\ne}0$ for the first type and ${c}_{123}=0$ for the second type. For both types of black holes, in addition to the mass and charge of the black holes, we show that the presence of the \ae{}ther field can also affect the size of the shadow. For the first type of black hole, it is shown that the shadow size increases with the parameter ${c}_{13}$, while for the second type of black hole, the shadow size still increases with ${c}_{13}$ but decreases with the parameter ${c}_{14}$. With these properties of the \ae{}ther parameters, we also discuss the observational constraints on these parameters by using the data of the first black hole image by the Event Horizon Telescope. In addition, we also explore the effect of the \ae{}ther field on the deflection angle of light and the time…

We report on measurements of the all-particle cosmic ray energy spectrum and composition in the PeV to EeV energy range using 3 years of data from the IceCube Neutrino Observatory. The IceTop detector measures cosmic ray induced air showers on the surface of the ice, from which the energy spectrum of cosmic rays is determined by making additional assumptions about the mass composition. A separate measurement is performed when IceTop data are analyzed in coincidence with the high-energy muon energy loss information from the deep in-ice IceCube detector. In this measurement, both the spectrum and the mass composition of the primary cosmic rays are simultaneously reconstructed using a neural network trained on observables from both detectors. The performance and relative advantages of these two distinct analyses are discussed, including the systematic uncertainties and the dependence on the hadronic interaction models, and both all-particle spectra as well as individual spectra for elemental groups are presented.

Dark matter (DM) could couple to Standard Model (SM) particles through a light mediator and this could be responsible for the observed DM abundances through $f\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}z\phantom{\rule{0}{0ex}}e\ensuremath{-}i\phantom{\rule{0}{0ex}}n$. Here, the authors identify an additional production channel through the decay of photons that have acquired an in-medium plasma mass. They contribute to the relic abundance, lowering by an order of magnitude the target cross-section for the lowest dark matter masses.

Black hole solutions in general relativity are simple. The frequency spectrum of linear perturbations around these solutions (i.e., the quasinormal modes) is also simple, and therefore it is a prime target for fundamental tests of black hole spacetimes and of the underlying theory of gravity. The following technical calculations must be performed to understand the imprints of any modified gravity theory on the spectrum: 1. Identify a healthy theory; 2. Find black hole solutions within the theory; 3. Compute the equations governing linearized perturbations around the black hole spacetime; 4. Solve these equations to compute the characteristic quasinormal modes. In this work (the first of a series) we assume that the background spacetime has spherical symmetry, that the relevant physics is always close to general relativity, and that there is no coupling between the perturbation equations. Under these assumptions, we provide the general numerical solution to step 4. We provide publicly available data files such that the quasinormal modes of any spherically symmetric spacetime can be…

Very light axion (fuzzy) dark matter would have an impact on CMB polarization. The authors examine two effects, from early and late axion oscillations, and use them to put constraints on the allowed mass and couplings of such particles. They also discuss prospects for future discovery.

Advanced methods for computing perturbative, quantum-gravitational scattering amplitudes show great promise for improving our knowledge of classical gravitational dynamics. This is especially true in the weak-field and arbitrary-speed (post-Minkowskian, PM) regime, where the conservative dynamics at 3PM order has been recently determined for the first time, via an amplitude calculation. Such PM results are most relevantly applicable to relativistic scattering (unbound orbits), while bound/inspiraling binary systems, the most frequent sources of gravitational waves for the LIGO and Virgo detectors, are most suitably modeled by the weak-field and slow-motion (post-Newtonian, PN) approximation. Nonetheless, it has been suggested that PM results can independently lead to improved modeling of bound binary dynamics, especially when taken as inputs for effective-one-body (EOB) models of inspiraling binaries. Here, we initiate a quantitative study of this possibility, by comparing PM, EOB and PN predictions for the binding energy of a two-body system on a quasicircular inspiraling orbit…

The authors study the two-body gravitational scattering of massive scalars in general spacetime dimensions in the limit when both the energies and the impact parameter are large, which is relevant for the scattering of two black holes. The two- body scattering angle between the two black holes up to the second post- Minkowskian order (2PM) is extracted, which in various limits agrees with known results.

A general scheme is presented for simulating gauge theories, with matter fields, on a digital quantum computer. A Trotterized time-evolution operator that respects gauge symmetry is constructed, and a procedure for obtaining time-separated, gauge-invariant correlators is detailed. We demonstrate the procedure on small lattices, including the simulation of a $2+1\mathrm{D}$ non-Abelian gauge theory.

The authors develop a factorization formula for the collinear limit of the Energy-Energy Correlator observable in generic field theories. This allows for resummation of logarithms, including an improvement of existing QCD results by two orders and applications to Super Yang-Mills theories.

An excess of $\ensuremath{\sim}10--20\text{ }\text{ }\mathrm{GeV}$ cosmic-ray antiprotons has been identified in the spectrum reported by the AMS-02 Collaboration. The systematic uncertainties associated with this signal, however, have made it difficult to interpret these results. In this paper, we revisit the uncertainties associated with the time, charge and energy-dependent effects of solar modulation, the antiproton production cross section, and interstellar cosmic-ray propagation. After accounting for these uncertainties, we confirm the presence of a $4.7\ensuremath{\sigma}$ antiproton excess, consistent with that arising from a ${m}_{\ensuremath{\chi}}\ensuremath{\approx}64--88\text{ }\text{ }\mathrm{GeV}$ dark matter particle annihilating to $b\overline{b}$ with a cross section of $\ensuremath{\sigma}v\ensuremath{\simeq}(0.8--5.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}26}\text{ }\text{ }{\mathrm{cm}}^{3}/\mathrm{s}$. If we allow for the stochastic acceleration of secondary antiprotons in supernova remnants, the data continue to favor a similar range of dark…

Anisotropic stresses are ubiquitous in nature, but their modeling in general relativity is poorly understood and frame dependent. We introduce the first study on the dynamical properties of anisotropic self-gravitating fluids in a covariant framework. Our description is particularly useful in the context of tests of the black hole paradigm, wherein ultracompact objects are used as black hole mimickers but otherwise lack a proper theoretical framework. We show the following: (i) anisotropic stars can be as compact and as massive as black holes, even for very small anisotropy parameters; (ii) the nonlinear dynamics of the $1+1$ system is in good agreement with linearized calculations, and shows that configurations below the maximum mass are nonlinearly stable; (iii) strongly anisotropic stars have vanishing tidal Love numbers in the black-hole limit; and (iv) their formation will usually be accompanied by gravitational-wave echoes at late times.

We present the first exploratory lattice QCD calculation of the pion valence quark distribution extracted from spatially separated current-current correlations in coordinate space. We show that an antisymmetric combination of vector and axial-vector currents provides direct information on the pion valence quark distribution. Using the collinear factorization approach, we calculate the perturbative tree-level kernel for this current combination and extract the pion valence distribution. The main goal of this article is to demonstrate the efficacy of this general lattice QCD approach in the reliable extraction of parton distributions. With controllable power corrections and a good understanding of the lattice systematics, this method has the potential to serve as a complementary to the many efforts to extract parton distributions in global analyses from experimentally measured cross sections. We perform our calculation on an ensemble of $2+1$ flavor QCD using the isotropic-clover fermion action, with lattice dimensions $3{2}^{3}\ifmmode\times\else\texttimes\fi{}96$ at a lattice…

Based on our previous QCD sum rule studies on hidden-charm pentaquark states, we discuss possible interpretations of the ${P}_{c}(4312)$, ${P}_{c}(4440)$, and ${P}_{c}(4457)$, which were recently observed by LHCb. Our results suggest that the ${P}_{c}(4312)$ can be well interpreted as the $[{\mathrm{\ensuremath{\Sigma}}}_{c}^{++}{\overline{D}}^{\ensuremath{-}}]$ bound state with ${J}^{P}=1/{2}^{\ensuremath{-}}$, while the ${P}_{c}(4440)$ and ${P}_{c}(4457)$ can be interpreted as the $[{\mathrm{\ensuremath{\Sigma}}}_{c}^{+}{\overline{D}}^{0}]$ bound state with ${J}^{P}=1/{2}^{\ensuremath{-}}$, the $[{\mathrm{\ensuremath{\Sigma}}}_{c}^{*++}{\overline{D}}^{\ensuremath{-}}]$ and $[{\mathrm{\ensuremath{\Sigma}}}_{c}^{+}{\overline{D}}^{*0}]$ bound states with ${J}^{P}=3/{2}^{\ensuremath{-}}$, or the $[{\mathrm{\ensuremath{\Sigma}}}_{c}^{*+}{\overline{D}}^{*0}]$ bound state with ${J}^{P}=5/{2}^{\ensuremath{-}}$. We propose to measure their spin-parity quantum numbers to verify these assignments.

Studies of on-shell and off-shell Higgs boson production in the four-lepton final state are presented, using data from the CMS experiment at the LHC that correspond to an integrated luminosity of 80.2 fb -1 at a center-of-mass energy of 13 TeV.Joint constraints are set on the Higgs boson total width and parameters that express its anomalous couplings to two electroweak vector bosons.These results are combined with those obtained from the data collected at center-of-mass energies of 7 and 8 TeV, corresponding to integrated luminosities of 5.1 and 19.7 fb -1 , respectively.Kinematic information from the decay particles and the associated jets are combined using matrix element techniques to identify the production mechanism and to increase sensitivity to the Higgs boson couplings in both production and decay.The constraints on anomalous HVV couplings are found to be consistent with the standard model expectation in both the onshell and off-shell regions.Under the assumption of a coupling structure similar to that in the standard model, the Higgs boson width is constrained to be 3.2…

We use a combined 1.2 Ms of NuSTAR observations of M31 to search for x-ray lines from sterile neutrino dark matter decay. For the first time in a NuSTAR analysis, we consistently take into account the signal contribution from both the focused and unfocused fields of view. We also reduce the modeling systematic uncertainty by performing spectral fits to each observation individually and statistically combining the results, instead of stacking the spectra. We find no evidence of unknown lines, and thus derive limits on the sterile neutrino parameters. Our results place stringent constraints for dark matter masses $\ensuremath{\gtrsim}12\text{ }\text{ }\mathrm{keV}$, which reduces the available parameter space for sterile neutrino dark matter produced via neutrino mixing (e.g., in the $\ensuremath{\nu}\mathrm{MSM}$) by approximately one-third. Additional NuSTAR observations, together with improved low-energy background modeling, could probe the remaining parameter space in the future. Lastly, we also report model-independent limits on generic dark matter decay rates and annihilation…

We present the simultaneous measurement of the interaction rates ${R}_{pp}$, ${R}_{\mathrm{Be}}$, ${R}_{pep}$ of $pp$, $^{7}\mathrm{Be}$, and $pep$ solar neutrinos performed with a global fit to the Borexino data in an extended energy range (0.19--2.93) MeV with particular attention to details of the analysis methods. This result was obtained by analyzing 1291.51 days of Borexino Phase-II data, collected after an extensive scintillator purification campaign. Using counts per day $(\mathrm{cpd})/100\text{ }\mathrm{ton}$ as unit, we find ${R}_{pp}=134\ifmmode\pm\else\textpm\fi{}10(\mathrm{stat}{)}_{\ensuremath{-}10}^{+6}(\mathrm{sys})$, ${R}_{Be}=\phantom{\rule{0ex}{0ex}}48.3\ifmmode\pm\else\textpm\fi{}1.1(\mathrm{stat}{)}_{\ensuremath{-}0.7}^{+0.4}(\mathrm{sys})$; and ${R}_{pep}^{\mathrm{HZ}}=2.43\ifmmode\pm\else\textpm\fi{}0.36(\mathrm{stat}{)}_{\ensuremath{-}0.22}^{+0.15}(\mathrm{sys})$ assuming the interaction rate ${R}_{\mathrm{CNO}}$ of CNO-cycle (Carbon, Nitrogen, Oxigen) solar neutrinos according to the prediction of the high metallicity standard solar model, and…

The phenomenological parametrizations of dark-energy (DE) equations of state can be very helpful, since they allow for the investigation of its cosmological behavior despite the fact that its underlying theory is unknown. However, although there has been a large amount of research on DE parametrizations which involve two or more free parameters, the one-parameter parametrizations seem to be underestimated. We perform a detailed observational confrontation of five one-parameter DE models, with observational data from cosmic microwave background (CMB), Joint light-curve analysis sample from Supernovae Type Ia observations (JLA), baryon acoustic oscillations (BAO) distance measurements, and cosmic chronometers (CC). We find that all models favor a phantom DE equation of state at present time, while they lead to ${H}_{0}$ values in perfect agreement with its direct measurements and therefore they offer an alleviation to the ${H}_{0}$-tension. Finally, performing a Bayesian analysis we show that although $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ cosmology is still favored,…

In the present work, we assign the newly observed ${P}_{c}(4312)$ as a $I({J}^{P})=\frac{1}{2}(\frac{1}{2}{)}^{\ensuremath{-}}$ molecular state composed of ${\mathrm{\ensuremath{\Sigma}}}_{c}\overline{D}$, while ${P}_{c}(4440)$ and ${P}_{c}(4457)$ as ${\mathrm{\ensuremath{\Sigma}}}_{c}{\overline{D}}^{*}$ molecular states with $I({J}^{P})=\frac{1}{2}(\frac{1}{2}{)}^{\ensuremath{-}}$ and $\frac{1}{2}(\frac{3}{2}{)}^{\ensuremath{-}}$, respectively. In this molecular scenario, we investigate the ${P}_{c}\ensuremath{\rightarrow}J/\ensuremath{\psi}p$ process of these three states and further predict the ratios of the $\mathcal{B}({P}_{c}\ensuremath{\rightarrow}J/\ensuremath{\psi}p)$ and those of $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}{P}_{c}K)$ between these three states, which could serve as a crucial test of the present molecular scenario.

Recently, the gravitational scattering of two black holes (BHs) treated at the leading order in the weak-field, or post-Minkowskian (PM), approximation to general relativity has been shown to map bijectively onto a simpler effectively one-body process: the scattering of a test BH in a stationary BH spacetime. Here, for BH spins aligned with the orbital angular momentum, we propose a simple extension of that mapping to 2PM order. We provide evidence for the validity and utility of this 2PM mapping by demonstrating its compatibility with all known analytical results for the conservative local-in-time dynamics of binary BHs in the post-Newtonian (weak-field and slow-motion) approximation and, separately, in the test-BH limit. Our result could be employed in the construction of improved effective-one-body models for the conservative dynamics of inspiraling spinning binary BHs.

Primordial black holes (PBHs) cannot be produced abundantly enough to be the dark matter in canonical single-field inflation under slow roll. This conclusion is robust to local non-Gaussian correlations between long- and short-wavelength curvature modes, which we show have no effect in slow roll on local primordial black hole abundances. For the prototypical model which evades this no-go, ultra-slow roll (USR), these squeezed non-Gaussian correlations have at most an order-unity effect on the variance of PBH-producing curvature fluctuations for models that would otherwise fail to form sufficient PBHs. Moreover, the transition out of USR, which is necessary for a successful model, suppresses even this small enhancement unless it causes a large increase in the inflaton kinetic energy in a fraction of an $e$-fold, which we call a large and fast transition. Along the way we apply the in-in formalism, the $\ensuremath{\delta}N$ formalism, and gauge transformations to compute non-Gaussianities and illuminate different aspects of the physical origin of these results. Local non-Gaussianity…

We present a novel approach for probing the microstructure of a thermodynamic system that combines thermodynamic phase transitions with the Ruppeiner scalar curvature. Originally considered for van der Waals fluids and charged black holes [Phys. Rev. Lett. 123, 071103 (2019)], we extend and generalize our approach to higher-dimensional charged AdS black holes. Beginning with thermodynamic fluctuations, we construct the line element of the Ruppeiner geometry and obtain a universal formula for the scalar curvature $R$. We first review the thermodynamics of a van der Waals fluid and calculate the coexistence and spinodal curves. From this we are able to clearly display the phase diagram. Notwithstanding the invalidity of the equation of state in the coexistence phase regions, we find that the scalar curvature is always negative for the van der Waals fluid, indicating that attractive interactions dominate among the fluid microstructures. Along the coexistence curve, the scalar curvature $R$ decreases with temperature, and goes to negative infinity at a critical temperature. We then…

Convolutional neural networks (CNNs) have recently been demonstrated on synthetic data to improve upon the precision of cosmological inference. In particular, they have the potential to yield more precise cosmological constraints from weak lensing mass maps than the two-point functions. We present the cosmological results with a CNN from the KiDS-450 tomographic weak lensing dataset, constraining the total matter density ${\mathrm{\ensuremath{\Omega}}}_{\mathrm{m}}$, the fluctuation amplitude ${\ensuremath{\sigma}}_{8}$, and the intrinsic alignment amplitude ${A}_{\mathrm{IA}}$. We use a grid of N-body simulations to generate a training set of tomographic weak lensing maps. We test the robustness of the expected constraints to various effects, such as baryonic feedback, simulation accuracy, a different value of ${H}_{0}$, or the light cone projection technique. We train a set of ResNet-based CNNs with varying depths to analyze sets of tomographic KiDS mass maps divided into 20 flat regions, with applied Gaussian smoothing of $\ensuremath{\sigma}=2.34\text{ }\text{…

We complete the derivation of the conservative dynamics of binary systems to fourth Post-Newtonian (4PN) order in the effective field theory (EFT) approach. We present a self-contained (ambiguity-free) computation of the renormalized Lagrangian, entirely within the confines of the PN expansion. While we confirm the final results reported in the literature, we clarify several issues regarding intermediate infrared (IR) and ultraviolet (UV) divergences, as well as the renormalization procedure. First, we properly identify the IR and UV singularities using (only) dimensional regularization and the method of regions, which are the pillars of the EFT formalism. This requires a careful study of scaleless integrals in the potential region, as well as conservative contributions from radiation modes due to tail effects. As expected by consistency, the UV divergences in the near region (due to the point-particle limit) can be absorbed into two counterterms in the worldline effective theory. The counterterms can then be removed by field redefinitions, such that the renormalization scheme…

In this paper, we analyze the deflection angle of light by Brane-Dicke wormhole in the weak field limit approximation to find the effect of the Brane-Dicke coupling parameter on the weak gravitation lensing. For this purpose, we consider new geometric techniques, i.e., Gauss-Bonnet theorem and optical geometry in order to calculate the deflection angle. Furthermore, we verify our results by considering the most familiar geodesic technique. Moreover, we establish the quantum corrected metric of Brane-Dicke wormhole by replacing the classical geodesic with Bohmian trajectories, whose matter source and anisotropic pressure are influenced by Bohmian quantum effects and calculate its quantum corrected deflection angle. Then, we calculate the deflection angle by naked singularities and compare with the result of wormhole's. Such a novel lensing feature might serve as a way to detect wormholes, naked singularities and also the evidence of Brane-Dicke theory.

If a wormhole smoothly connects two different spacetimes, then the flux cannot be separately conserved in any of these spaces individually. Then objects propagating in the vicinity of a wormhole in one space must feel the influence of objects propagating in the other space. We show this in the cases of the scalar, electromagnetic, and gravitational field. The case of gravity is perhaps the most interesting. Namely, by studying the orbits of stars around the black hole at the center of our galaxy, we could soon tell if this black hole harbors a traversable wormhole. In particular, with a near future acceleration precision of ${10}^{\ensuremath{-}6}\text{ }\text{ }\mathrm{m}/{\mathrm{s}}^{2}$, a few solar masses star orbiting around Sgr A* on the other side of the wormhole at the distance of a few gravitational radii would leave a detectable imprint on the orbit of the S2 star on our side. Alternatively, one can expect the same effect in black hole binary systems, or a black hole--star binary systems.

In the last few years, machine learning techniques, in particular convolutional neural networks, have been investigated as a method to replace or complement traditional matched filtering techniques that are used to detect the gravitational-wave signature of merging black holes. However, to date, these methods have not yet been successfully applied to the analysis of long stretches of data recorded by the Advanced LIGO and Virgo gravitational-wave observatories. In this work, we critically examine the use of convolutional neural networks as a tool to search for merging black holes. We identify the strengths and limitations of this approach, highlight some common pitfalls in translating between machine learning and gravitational-wave astronomy, and discuss the interdisciplinary challenges. In particular, we explain in detail why convolutional neural networks alone cannot be used to claim a statistically significant gravitational-wave detection. However, we demonstrate how they can still be used to rapidly flag the times of potential signals in the data for a more detailed follow-up.…

Horndeski gravity is the most general scalar tensor theory, with a single scalar field, leading to second-order field equations and after the GW170817 it has been severely constrained. Since this theory is very important in modified gravity, it is then worth studying possible similar theories starting from other frameworks. In this paper, we study the analog of Horndeski's theory in the teleparallel gravity framework where gravity is mediated through torsion instead of curvature. We show that, even though many terms are the same as in the curvature case, we have much richer phenomenology in the teleparallel setting because of the nature of the torsion tensor. Moreover, teleparallel Horndeski contains the standard Horndeski gravity as a subcase and also contains many modified teleparallel theories considered in the past, such as $f(T)$ gravity or teleparallel dark energy. Thus, due to the appearance of a new term in the Lagrangian, this theory can explain dark energy without a cosmological constant, may describe a crossing of the phantom barrier, explain inflation and also solve the…

We present a comprehensive analysis of neutrino mass and lepton mixing in theories with ${A}_{5}$ modular symmetry. We construct the weight 2, weight 4, and weight 6 modular forms of level 5 in terms of Dedekind eta-functions and Klein forms, and their decomposition into irreducible representation of ${A}_{5}$. We construct all the simplest models based on ${A}_{5}$ modular symmetry, including scenarios of models with and without flavons in the charged lepton sectors. For each case, the neutrino masses can be generated through either the Weinberg operator or the type I seesaw mechanism. We perform an exhaustive numerical analysis, organizing our results in an extensive set of figures and tables.

Four-dimensional Minkowskian scattering amplitudes can also be presented in a basis of a different group ($S\phantom{\rule{0}{0ex}}L(2,C)$), which acts as the conformal group on the celestial two-sphere at null infinity. This type of representation is useful for understanding the flat-space holography. The authors propose a procedure for taking the (conformally) soft limit of tree-level scattering amplitudes in this basis.

The unprecedented quality of the data collected by the AMS-02 experiment onboard the International Space Station allowed us to address subtle questions concerning the origin and propagation of cosmic rays. Here we discuss the implications of these data for the injection spectrum of elements with different masses and for the diffusion coefficient probed by cosmic rays through their journey from the sources to the Earth. We find that the best fit to the spectra of primary and secondary nuclei requires (1) a break in the energy dependence of the diffusion coefficient at energies $\ensuremath{\sim}300\text{ }\text{ }\mathrm{GV}$; (2) an injection spectrum that is the same for all nuclei heavier than helium, and different injections for both protons and helium. Moreover, if to force the injection spectrum of helium to be the same as for heavier nuclei, the fit to oxygen substantially worsens. Accounting for a small, ${X}_{s}\ensuremath{\sim}0.4\text{ }\text{ }\mathrm{g}\text{ }{\mathrm{cm}}^{\ensuremath{-}2}$, grammage accumulated inside the sources leads to a somewhat better fit to the…