The 50 most-cited articles in Physics Letters B, 2023

We propose a new model-independent mechanism for producing primordial black holes from a period of multi-field inflation. This requires an enhancement of primordial fluctuations at short scales compared to their value at CMB scales. We show that such an amplification naturally occurs when the inflationary trajectory exhibits a strong turn, that is a limited period during which the trajectory strongly deviates from a geodesic in field space, and is sufficient for subsequently producing primordial black holes with the abundance to be all or a fraction of dark matter. Our mechanism is generic to models of inflation realized in a multi-dimensional field space with an overlying potential and geometry, also referred to as the inflationary landscape, as arises in embeddings of inflation in high-energy theories. We study analytically and numerically how the duration and the strength of the turn impact the primordial fluctuation power spectrum and the abundance of primordial black holes. Our mechanism has the potential of exhibiting unique features accessible to observation through the…

Using the Effective Field Theory (EFT) framework of single field inflation, we investigate the possibility of the formation of Primordial Black Holes (PBHs) in the Slow Roll (SR) to Ultra Slow Roll (USR) sharp transition. We demonstrate that, due to one-loop correction to the power spectrum, causality is violated (cs>1) for the mass range of PBHs, MPBH>102gm created during the said transition. We find that non-canonical features with cs<1 worsen the predictions of the canonical framework of single-field inflation.

Many extensions of the Standard Model predict the production of dark matter particles at the LHC. Sufficiently light dark matter particles may be produced in decays of the Higgs boson that would appear invisible to the detector. This Letter presents a statistical combination of searches for H→invisible decays where multiple production modes of the Standard Model Higgs boson are considered. These searches are performed with the ATLAS detector using 139 fb−1 of proton–proton collisions at a centre–of–mass energy of at the LHC. In combination with the results at and , an upper limit on the H→invisible branching ratio of 0.107 (0.077) at the 95% confidence level is observed (expected). These results are also interpreted in the context of models where the 125 GeV Higgs boson acts as a portal to dark matter, and limits are set on the scattering cross-section of weakly interacting massive particles and nucleons.

The well-known correspondence between quasinormal modes of any stationary, spherically symmetric and asymptotically flat or de Sitter black hole and parameters of the circular null geodesic was initially claimed for gravitational and test field perturbations. According to this correspondence the real and imaginary parts of the ℓ≫n quasinormal mode (where ℓ and n are multipole and overtone numbers respectively) are multiples of the frequency and instability timescale of the circular null geodesics respectively. Later it was shown that the correspondence is guaranteed only for test fields and may be broken for gravitational and other non-minimally coupled fields. Here, we further specify the correspondence and prove that even when it is guaranteed, it may not represent the full spectrum of the ℓ≫n modes, missing the quasinormal frequencies which cannot be found by the standard WKB method. In particular we show that this always happens for an arbitrary asymptotically de Sitter black holes and further argue that, in general, this might be related to sensitivity of the quasinormal…

The current study deals with the new wormhole solutions in the background of fourth order new modified Ricci inverse gravity. Two new classes of the wormhole solutions are analyzed by showing the valid region for the main part of wormhole geometry under the affect of involved parameters. The embedded diagrams for both generic shape functions are also presented, which are connecting upper and lower Universes. In order to check the existence of these wormhole solutions, energy conditions are included in the current analysis. In the maximum regions, all energy conditions are violated, which confirms the presence of exotic matter in the background of Ricci inverse gravity. Stability analysis for both wormhole solutions is explored within the scope of speed of sounds parameters. Conclusively, some highlights from this research confirm the realistic nature and viability of these wormhole solutions in Ricci inverse gravity.

Measurements are presented of the Bs0→μ+μ− branching fraction and effective lifetime, as well as results of a search for the B0→μ+μ− decay in proton-proton collisions at s=13TeV at the LHC. The analysis is based on data collected with the CMS detector in 2016–2018 corresponding to an integrated luminosity of 140fb−1. The branching fraction of the Bs0→μ+μ− decay and the effective Bs0 meson lifetime are the most precise single measurements to date. No evidence for the B0→μ+μ− decay has been found. All results are found to be consistent with the standard model predictions and previous measurements.

We explore the possibility that a confining first-order phase transition of a nearly-conformal dark sector generates the reported NANOGrav signal of a stochastic gravitational wave background. The visible Standard Model (SM) sector and the dark sector are initially thermally decoupled so that their temperatures are different. The nearly conformal phase transition is described by the shallow potential of a dilaton (or a radion in the 5D holographic perspective) generated by a new dark Yang-Mills field coupled to the conformal sector. For a dark sector only gravitationally connected with the visible sector, the NANOGrav signal is explained by the phase transition without contradicting the ΔNeff constraint, together with a contribution from supermassive black hole binaries. While the dilaton and dark glueballs can be produced after the phase transition, they immediately decay into dark radiation, which can help ameliorate the Hubble tension and be tested by the future CMB-S4 experiment. Alternatively, for a dark conformal sector decaying into the visible sector after the phase…

Precision tests of first-row unitarity of the Cabibbo–Kobayashi–Maskawa matrix currently display two intriguing tensions, both at the 3σ level. First, combining determinations of Vud from superallowed β decays with Vus from kaon decays suggests a deficit in the unitarity relation. At the same time, a tension of similar significance has emerged between Kℓ2 and Kℓ3 decays. In this Letter, we point out that a measurement of the Kμ3/Kμ2 branching fraction at the level of 0.2% would have considerable impact on clarifying the experimental situation in the kaon sector, especially in view of tensions in the global fit to kaon data as well as the fact that the Kμ2 channel is currently dominated by a single experiment. Such a measurement, as possible for example at NA62, would further provide important constraints on physics beyond the Standard Model, most notably on the role of right-handed vector currents.

We propose two possible eikonal operators encoding the effects of classical radiation as coherent states of gravitons and show how to compute from them different classical observables. In the first proposal, only genuinely propagating gravitons are included, while, in the second, zero-frequency modes are added in order to recover the effects of a static gravitational field. We first calculate the radiated energy-momentum and the change in each particle's momentum, or impulse, to 3PM order finding agreement with the literature. We then calculate the angular momentum of the gravitational field after the collision. In order to do so, we adapt the method of reverse unitarity to the presence of derivatives in the operators describing the angular momentum and reproduce the result of [1] obtained by resumming the small-velocity expansion. As a new application, we derive also the variation in each particle's angular momentum up to 3PM: calculating separately field and particle contributions allows us to check the balance laws explicitly. We also show how the eikonal operator encodes the…

In this work, a refined Bayesian neural network (BNN) based approach with six inputs including the proton number, mass number, and engineered features associated with the pairing effect, shell effect, isospin effect, and “abnormal” shape staggering effect of 181,183,185Hg, is proposed to accurately describe nuclear charge radii. The new approach is able to well describe the charge radii of atomic nuclei with A≥40 and Z≥20. The standard root-mean-square deviation is 0.014 fm for both the training and validation data. In particular, the predicted charge radii of proton-rich and neutron-rich calcium isotopes are found in good agreement with data. We further demonstrate the reliability of the BNN approach by investigating the variations of the root-mean-square deviations with extrapolation distances, mass numbers, and isospin asymmetries.

Constraints on the Higgs boson self-coupling are set by combining double-Higgs boson analyses in the bb¯bb¯, bb¯τ+τ− and bb¯γγ decay channels with single-Higgs boson analyses targeting the γγ, ZZ⁎, WW⁎, τ+τ− and bb¯ decay channels. The data used in these analyses were recorded by the ATLAS detector at the LHC in proton–proton collisions at s=13 TeV and correspond to an integrated luminosity of 126–139 fb−1. The combination of the double-Higgs analyses sets an upper limit of μHH<2.4 at 95% confidence level on the double-Higgs production cross-section normalised to its Standard Model prediction. Combining the single-Higgs and double-Higgs analyses, with the assumption that new physics affects only the Higgs boson self-coupling (λHHH), values outside the interval −0.4<κλ=(λHHH/λHHHSM)<6.3 are excluded at 95% confidence level. The combined single-Higgs and double-Higgs analyses provide results with fewer assumptions, by adding in the fit more coupling modifiers introduced to account for the Higgs boson interactions with the other Standard Model particles. In this relaxed scenario, the…

Recently, Belle II reported on the first measurement of B(B±→K±νν¯) which appears to be almost 3σ larger than predicted in the Standard Model. We point out the important correlation with B(B→K⁎νν¯) so that the measurement of that decay mode could help restrain the possible options for building the model of New Physics. We interpret this new experimental result in terms of physics beyond the Standard Model by using SMEFT and find that a scenario with coupling only to τ can accommodate the current experimental constraints but fails in getting a desired RD(⁎)exp/RD(⁎)SM, unless one turns the other SMEFT operators that are not related to b→sℓℓ or/and b→sνν.

The CMS collaboration has recently reported the results of a low-mass Higgs-boson search in the di-photon final state based on the full Run 2 data set with refined analysis techniques. The new results show an excess of events at a mass of about 95GeV with a local significance of 2.9σ, confirming a previously reported excess at about the same mass and similar significance based on the first-year Run 2 plus Run 1 data. The observed excess is compatible with the limits obtained in the corresponding ATLAS searches. In this work, we discuss the di-photon excess and show that it can be interpreted as the lightest Higgs boson in the Two-Higgs doublet model that is extended by a complex singlet (S2HDM) of Yukawa types II and IV. We show that the second-lightest Higgs boson is in good agreement with the current LHC Higgs-boson measurements of the state at 125 GeV, and that the full scalar sector is compatible with all theoretical and experimental constraints. Furthermore, we discuss the di-photon excess in conjunction with an excess in the bb¯ final state observed at LEP and an excess…

We provide a moduli-dependent definition of species scale in quantum gravity based on black hole arguments. Concretely, it is derived from a lower bound on the entropy of extremal black holes with higher curvature corrections, which ensures that the black hole can be reliably described within the effective theory. By demanding that our definition coincides with a recent proposal for a moduli-dependent species scale motivated from the topological string, we conclude that the conjecture ZBH=|Ztop|2 relating the black hole to the topological string partition functions should hold, at least within the regime of validity of our analysis.

We study the formation and evolution of domain walls with initial inflationary fluctuations by numerical lattice calculations that, for the first time, correctly take into account correlations on superhorizon scales. We find that, contrary to the widely-held claim over the past few tens of years, the domain wall network exhibits remarkable stability even when the initial distribution is largely biased toward one of the minima. This is due to the fact that the domain wall network retains information about initial conditions on superhorizon scales, and that the scaling solution is not a local attractor in this sense. Our finding immediately implies that such domain walls will have a significant impact on cosmology, including the production of gravitational waves, baryogenesis, and dark matter from domain walls. Applying this result to the axion-like particle domain wall, we show that it not only explains the isotropic cosmic birefringence suggested by the recent analysis, but also predicts anisotropic cosmic birefringence that is nearly scale-invariant on large scales and can be…

The existence of ultralight axion (ULA) with mass O(10−26eV) is not favored by the CMB observations in the standard ΛCDM model. We show that the inclusion of early dark energy (EDE) will lift the CMB-lockdown on such ULA, and possibly other forms of dark matter beyond cold dark matter. By performing Monte Carlo Markov Chain analysis, it is found that, as opposed to ΛCDM, the AdS-EDE cosmology (with an Anti-de Sitter phase around recombination) now allows the existence of axion with mass 10−26 eV and predicts 6% of the matter in our Universe to be such ULA, which can also help alleviating the S8 tension in EDE.

Next generation direct dark matter detection experiments are favorable facilities to probe neutrino properties and light mediators beyond the Standard Model. We explore the implications of the recent data reported by LUX-ZEPLIN (LZ) and XENONnT collaborations on electromagnetic neutrino interactions and neutrino generalized interactions (NGIs). We show that XENONnT places the most stringent upper limits on the effective and transition neutrino magnetic moment (of the order of few ×10−12μB) as well as stringent constraints to neutrino millicharge (of the order of ∼10−13e)–competitive to LZ–and improved by about one order of magnitude in comparison to existing constraints coming from Borexino and TEXONO. We furthermore explore the XENONnT and LZ sensitivities to simplified models with light NGIs and find improved constraints in comparison to those extracted from Borexino-Phase II data.

We face the inverse problem of obtaining the interaction between coupled channels from the correlation functions of these channels. We apply the method to the interaction of the D0K+, D+K0, and Ds+η channels, from where the Ds0⁎(2317) state emerges. We use synthetic data extracted from an interaction model based on the local hidden gauge approach and find that the inverse problem can determine the existence of a bound state of the system with a precision of about 20 MeV. At the same time, we can determine the isospin nature of the bound state and its compositeness in terms of the channels. Furthermore, we evaluate the scattering length and effective range of all three channels, as well as the couplings of the bound state found to all the components. Lastly, the size parameter of the source function, R, which in principle should be a magnitude provided by the experimental teams, can be obtained from a fit to the data with relatively high accuracy. These findings show the value of the correlation function to learn about the meson–meson interaction for systems which are difficult to…

We study an axion-like particle (ALP) that experiences a first-order phase transition with respect to its mass or potential minimum. This can be realized if the ALP obtains a potential from non-perturbative effects of SU(N) gauge theory that is confined via the first-order phase transition. Similar dynamics are achieved in the so-called trapped misalignment mechanism, where the ALP is trapped in a false vacuum at high temperatures until it begins to oscillate about the true minimum. The resulting ALP abundance is significantly enhanced compared to the standard misalignment mechanism, explaining dark matter in a broader parameter space that is accessible to experiments e.g. IAXO, ALPS-II, and DM-radio. Furthermore, the viable parameter space includes a region of the mass ma≃10−8−10−7 eV and the ALP-photon coupling gaγγ≃10−11GeV−1 that can explain the recent observation of very high energy photons from GRB221009A via axion-photon oscillations. The parameter region suggests that the FOPT can generate gravitational waves that explain the NANOGrav hint. If the ALP in this region explains…

The FASER experiment at the LHC is designed to search for light, weakly-interacting particles produced in proton-proton collisions at the ATLAS interaction point that travel in the far-forward direction. The first results from a search for dark photons decaying to an electron-positron pair, using a dataset corresponding to an integrated luminosity of 27.0 fb−1 collected at center-of-mass energy s=13.6 TeV in 2022 in LHC Run 3, are presented. No events are seen in an almost background-free analysis, yielding world-leading constraints on dark photons with couplings ϵ∼2×10−5−1×10−4 and masses ∼17MeV−70MeV. The analysis is also used to probe the parameter space of a massive gauge boson from a U(1)B−L model, with couplings gB−L∼5×10−6−2×10−5 and masses ∼15MeV−40MeV excluded for the first time.

Static and stationary regular black holes are examined under a minimal set of requirements consisting of (i) the existence of a well defined event horizon and (ii) the weak energy condition for matter sourcing the geometry. We perform our analysis by means of the gravitational decoupling approach and find hairy solutions free of curvature singularities. We identify the matter source producing a deformation of the Minkowski vacuum such that the maximum deformation is the Schwarzschild solution for the static case, and the Kerr metric for the stationary case.

The genuine entanglement of Dirac fields for an N-partite system is investigated in Schwarzschild spacetime and the analysis is carried out using the single-mode approximation. Due to the Hawking effect, quantum entanglement is divided into two parts physically accessible and inaccessible entanglement. We obtain a general analytic expression of genuine N-partite entanglement that includes all accessible and inaccessible entanglement in a Schwarzschild black hole. Unlike bosonic entanglement, the accessible N-partite entanglement of Dirac fields monotonically decreases to a nonzero value with the Hawking temperature. Interestingly, the inaccessible N-partite entanglement is a monotonic or non-monotonic function of the Hawking temperature, depending on the ratio between accessible and inaccessible modes, in contrast to bipartite or tripartite entanglement that is only a monotonic function of the Hawking temperature. Finally, we obtain two restrictive relationships for the quantum information of the black hole. This conclusion provides a new understanding of Hawking effect of the black…

Interactions of cosmic ray protons, atomic nuclei, and electrons in the interstellar medium in the inner part of the Milky Way produce a γ-ray flux from the Galactic Ridge. If the γ-ray emission is dominated by proton and nuclei interactions, a neutrino flux comparable to the γ-ray flux is expected from the same sky region. Data collected by the ANTARES neutrino telescope are used to constrain the neutrino flux from the Galactic Ridge in the 1-100 TeV energy range. Neutrino events reconstructed both as tracks and showers are considered in the analysis and the selection is optimized for the search of an excess in the region |l|<30°, |b|<2°. The expected background in the search region is estimated using an off-zone region with similar sky coverage. Neutrino signal originating from a power-law spectrum with spectral index ranging from Γν=1 to 4 is simulated in both channels. The observed energy distributions are fitted to constrain the neutrino emission from the Ridge. The energy distributions in the signal region are inconsistent with the background expectation at ∼96% confidence…

The question of the existence and possible magnitude of nonperturbative (often called “intrinsic”) charm in the proton has long confounded attempts to cleanly isolate such a contribution in global analyses of high-energy experiments. In this letter, we show that the available (non)perturbative QCD theory and hadronic data have still not developed to a sufficient level to clearly resolve this problem. We highlight a number of challenging aspects that must be confronted in extracting nonperturbative charm in PDF fits, and in so doing, present an updated next-to-next-to-leading order CT analysis of fitted charm, CT18 FC, which we also compare to recent studies. We outline the theory developments and future data needed to make progress on this subject.

We have a look at the Pcs states generated from the interaction of D¯(⁎)Ξc(′⁎) coupled channels. We consider the blocks of pseudoscalar-baryon (12+,32+) and vector-baryon (12+,32+), and find 10 resonant states coupling mostly to D¯Ξc,D¯⁎Ξc,D¯Ξc′,D¯⁎Ξc′,D¯Ξc⁎ and D¯⁎Ξc⁎. A novel aspect of the work is the realization that the D¯Ξc,D¯sΛc or D¯⁎Ξc,D¯s⁎Λc channels, with a strong transition potential, collaborate to produce a larger attraction than the corresponding states D¯Σc,D¯Λc or D¯⁎Σc,D¯⁎Λc appearing in the generation of the strangenessless Pc states, since in the latter case the transition potential between those channels is zero. The extra attraction obtained in the D¯Ξc,D¯⁎Ξc pairs preclude the association of these channels to the Pcs(4338) and Pcs(4459) states respectively. Then we find a natural association of the Pcs(4338) state coupling mostly to D¯⁎Ξc while the Pcs(4459) is associated to the state found that couples mostly to D¯Ξc′. Four more states appear, like in other molecular pictures, and some of the states are degenerate in spin. Counting different spin states we…

We construct new effective interactions using the relativistic mean-field models with the isoscalar- and isovector-meson mixing, σ2δ2 and ωμωμρνρν. Taking into account the particle flow data in heavy-ion collisions, the observed mass of PSR J0740+6620, and the tidal deformability of a neutron star from the binary merger event, GW170817, we study the ground-state properties of finite, closed-shell nuclei, and try to explain the recent results from the PREX-2 and CREX experiments. It is found that the σ–δ mixing is very powerful to understand the terrestrial experiments and astrophysical observations of neutron stars self-consistently. We can predict the large neutron skin thickness of 208Pb, Rskin208=0.243 fm, using the slope parameter of nuclear symmetry energy, L=70 MeV, which is consistent with the PREX-2 result. However, to explain the CREX data, it is preferable to adopt the small value of L=20 MeV. It is very difficult to understand the PREX-2 and CREX results simultaneously within relativistic mean-field models.

It was recently shown that the dispersion relations describing singularities of retarded two-point functions in causal quantum field theories always satisfy the fundamental inequality Imω≤|Imk|, and that several rigorous bounds on transport coefficients follow directly from such inequality. Here, we prove that the same inequality, Imω≤|Imk|, is a necessary condition for a fluid theory to be covariantly stable (i.e. stable in all frames of reference). Hence, the same bounds on transport that follow from causality in quantum field theory also emerge as stability conditions within relativistic hydrodynamics. This intimate connection between bounds from causality and bounds from stability stems from the fact that covariant stability is possible only in the presence of causality. As a quick application, we show that fluids with luminal speed of sound have vanishing viscosities.

The production of prompt Λc+ baryons at midrapidity (|y|<0.5) was measured in central (0–10%) and mid-central (30–50%) Pb–Pb collisions at the center-of-mass energy per nucleon–nucleon pair sNN=5.02 TeV with the ALICE detector. The results are more precise, more differential in centrality, and reach much lower transverse momentum (pT=1 GeV/c) with respect to previous measurements performed by the ALICE, STAR, and CMS Collaborations in nucleus–nucleus collisions, allowing for an extrapolation down to pT=0. The pT-differential Λc+/D0 ratio is enhanced with respect to the pp measurement for 4<pT<8 GeV/c by 3.7 standard deviations (σ), while the pT-integrated ratios are compatible within 1σ. The observed trend is similar to that observed in the strange sector for the Λ/KS0 ratio. Model calculations including coalescence or statistical hadronization for charm-hadron formation are compared with the data.

The flavor evolution of neutrinos in core collapse supernovae and neutron star mergers is a critically important unsolved problem in astrophysics. Following the electron flavor evolution of the neutrino system is essential for calculating the thermodynamics of compact objects as well as the chemical elements they produce. Accurately accounting for flavor transformation in these environments is challenging for a number of reasons, including the large number of neutrinos involved, the small spatial scale of the oscillation, and the nonlinearity of the system. We take a step in addressing these issues by presenting a method which describes the neutrino fields in terms of angular moments. We apply our moment method to neutron star merger conditions and show it simulates fast flavor neutrino transformation in a region where this phenomenon is expected to occur. By comparing with particle-in-cell calculations we show that the moment method is able to capture the three phases of growth, saturation, and decoherence, and correctly predicts the lengthscale of the fastest growing fluctuations…

We study a power-law F(R) gravity with an early dark energy term, that can describe both the early-time and the late-time acceleration of the Universe. We confront this scenario with recent observational data including the Pantheon Type Ia supernovae, measurements of the Hubble parameter H(z) (Cosmic Chronometers), data from Baryon Acoustic Oscillations and standard rulers data from the Cosmic Microwave Background (CMB) radiation. The model demonstrates some achievements in confronting with these observations and can be compared with the Λ-Cold-Dark-Matter model. In particular, in both models we obtain very close estimates for the Hubble constant H0, but it is not true for Ωm0. The early dark energy term supports viability of the considered F(R) gravity model.

We have conducted a study of the femtoscopic correlation functions for the D0D⁎+ and D+D⁎0 channels that build the Tcc state. We develop a formalism that allows us to factorize the scattering amplitudes outside the integrals in the formulas, and the integrals involve the range of the strong interaction explicitly. For a source of size of 1 fm, we find values for the correlation functions of the D0D⁎+ and D+D⁎0 channels at the origin around 30 and 2.5, respectively, and we see these observables converging to unity already for relative momenta of the order of 200 MeV. We conduct tests to see the relevance of the different contributions to the correlation function and find that it mostly provides information on the scattering length, but should the correlation functions be measured with the precision of the latest experiments, the effective range of the D0D⁎+ could also be obtained.

We propose a novel many-body framework combining the density matrix renormalization group (DMRG) with the valence-space (VS) formulation of the in-medium similarity renormalization group. This hybrid scheme admits for favorable computational scaling in large-space calculations compared to direct diagonalization. The capacity of the VS-DMRG approach is highlighted in ab initio calculations of neutron-rich nickel isotopes based on chiral two- and three-nucleon interactions, and allows us to perform converged ab initio computations of ground and excited state energies. We also study orbital entanglement in the VS-DMRG, and investigate nuclear correlation effects in oxygen, neon, and magnesium isotopes. The explored entanglement measures reveal nuclear shell closures as well as pairing correlations.

We have computed the even-N moments N≤20 of the pure-singlet quark splitting function Pps at the fourth order of perturbative QCD via the anomalous dimensions of off-shell flavour-singlet operator matrix elements. Our results, derived analytically for a general gauge group, agree with all results obtained for this function so far, in particular with the lowest six even moments obtained via physical cross sections. Using these results and all available endpoint constraints, we construct approximations for Pps at four loops that should be sufficient for most collider-physics applications. Together with the known results for the non-singlet splitting function Pns+ at this order, this effectively completes the quark-quark contribution for the evolution of parton distribution at N3LO accuracy. Our new results thus provide a major step towards fully consistent N3LO calculations at the LHC and the reduction of the residual uncertainty in the parton evolution to the percent level.

The recent observations by pulsar timing array (PTA) experiments suggest the existence of stochastic gravitational wave background in the nano-Hz range. It can be a hint for the new physics and cosmic string is one of the promising candidates. In this paper, we study the implication of the PTA result for cosmic strings and dark photon dark matter produced by the decay of cosmic string loops. It can simultaneously explain the PTA result and present dark matter abundance for the dark photon mass m∼10−7–10−5eV. Implications for the gravitational wave detection with multi-frequency bands are also discussed.

Halo phenomena have long been an important frontier in both experimental and theoretical nuclear physics. 37Mg was identified as a halo nucleus in 2014 and remains the heaviest nuclear halo system to date. While the halo phenomenon in 37Mg was not predicted before the discovery, its description has been still challenging afterwards. In this Letter, we report a microscopic and self-consistent description of the neutron halo in 37Mg using the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) that was developed in 2010. The experimental neutron separation energies and empirical matter radii of neutron-rich magnesium isotopes as well as the deformed p-wave halo characteristics of 37Mg are well reproduced without any free parameters. In particular, the orbital occupied by the halo neutron in 37Mg, exhibiting p-wave components comparable to those suggested in experiments, remains consistent across various employed density functionals including PC-F1, PC-PK1, NL3*, and PK1. The DRHBc theory investigated only even-even magnesium isotopes in previous works and for that…

We are interested in a fermion-antifermion pair in magnetized 2+1 dimensional optical background with constant negative curvature. One implements this background for obtaining the optical metric of the BTZ black hole similar to the hyperbolic wormhole. To analyze the evolution of the considered system, we start with constructing the corresponding form of a one-time fully-covariant many-body Dirac equation derived from quantum electrodynamics. The associated equation leads 4×4 dimensional matrix equation resulting in a set of coupled equations consisting of four first-order equations since the two-body equation possesses spin algebra constructed through the Kronecker product of the generalized Dirac matrices. Also, we show a nonperturbative wave equation for the considered system. Accordingly, we seek analytical solutions to the wave equation. We obtain that relativistic energy of the system depends on the parameters of the background as well as the magnetic field. Also, we adapt the results to a Weyl pair. Our results imply that the lifetime of such a pair can be actively tuned, in…

Klein-Gordon (KG) particles in cosmic string rainbow gravity spacetime and a uniform magnetic field are studied in the context of the so called, effectively speaking, position-dependent mass (PDM) settings. We show that the corresponding KG-equation collapses into a two-dimensional radial Schrödinger-Coulomb like model. The exact textbook solution of which is used to find the energies and wave functions of KG-Coulomb particles (both constant mass and PDM ones). In so doing, we consider, with y=E/EP, four pairs of rainbow functions: (a) g0(y)=1, g1(y)=1−ϵy2, (b) g0(y)=1, g1(y)=1−ϵy, (c) g0(y)=g1(y)=(1−ϵy)−1, and (d) g0(y)=(eϵy−1)/ϵy, g1(y)=1. Interestingly, we observe that the first pair in (a) introduces the Planck energy Ep as a maximum possible KG-particle/antiparticle energy value.

Based on the structure input directly from the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc), we fully study reaction observables to search for halo evidence of 37Mg with the Glauber model. In this scheme, we evaluate the reaction cross sections of 20–37Mg bombarding a C target at 240 MeV/nucleon and find that most of the results agree well with the experimental data within 1σ uncertainty, especially good for the case of 37Mg. Our predicted doubling of the cross section change from 36Mg to 37Mg over that from 34Mg to 35Mg is consistent with a halo structure in 37Mg. Additionally, our calculated narrow longitudinal momentum distribution of 36Mg residues from 37Mg + 12C breakup agree well with data and imply a nuclear size much larger than 35Mg. Furthermore, our study shows a dominant p-wave contribution to the longitudinal momentum distribution, supporting the conclusion that 37Mg is a p-wave halo nucleus. Our study provides the first unified description of the halo characteristics of 37Mg from nuclear structure to reaction dynamics.

The observation of the production of four top quarks in proton-proton collisions is reported, based on a data sample collected by the CMS experiment at a center-of-mass energy of 13 TeV in 2016–2018 at the CERN LHC and corresponding to an integrated luminosity of 138fb−1. Events with two same-sign, three, or four charged leptons (electrons and muons) and additional jets are analyzed. Compared to previous results in these channels, updated identification techniques for charged leptons and jets originating from the hadronization of b quarks, as well as a revised multivariate analysis strategy to distinguish the signal process from the main backgrounds, lead to an improved expected signal significance of 4.9 standard deviations above the background-only hypothesis. Four top quark production is observed with a significance of 5.6 standard deviations, and its cross section is measured to be 17.7−3.5+3.7(stat)−1.9+2.3(syst)fb, in agreement with the available standard model predictions.

In lattice-QCD calculations of parton distribution functions (PDFs) via large-momentum effective theory, the leading power (twist-three) correction appears as O(ΛQCD/Pz) due to the linear-divergent self-energy of Wilson line in quasi-PDF operators. For lattice data with hadron momentum Pz of a few GeV, this correction is dominant in matching, as large as 30% or more. We show how to eliminate this uncertainty through choosing the mass renormalization parameter consistently with the resummation scheme of the infrared-renormalon series in perturbative matching coefficients. An example on the lattice pion PDF data at Pz=1.9 GeV shows an improvement of matching accuracy by a factor of more than 3∼5 in the expansion region x=0.2∼0.5.

Generalized entropy, that has been recently proposed, puts all the known and apparently different entropies like The Tsallis, the Rényi, the Barrow, the Kaniadakis, the Sharma-Mittal and the loop quantum gravity entropy within a single umbrella. However, the microscopic origin of such generalized entropy as well as its relation to thermodynamic system(s) is not clear. In the present work, we will provide a microscopic thermodynamic explanation of generalized entropy(ies) from canonical and grand-canonical ensembles. It turns out that in both the canonical and grand-canonical descriptions, the generalized entropies can be interpreted as the statistical ensemble average of a series of microscopic quantity(ies) given by various powers of (−kln⁡ρ)n (with n being a positive integer and ρ symbolizes the phase space density of the respective ensemble), along with a term representing the fluctuation of Hamiltonian and number of particles of the system under consideration (in case of canonical ensemble, the fluctuation on the particle number vanishes).

In this work, we study the thermodynamic properties on a non–commutative background via gravitational gauge field potentials. This procedure is accomplished after contracting de Sitter (dS) group, SO(4,1), with the Poincarè group, ISO(3,1). Particularly, we focus on a static spherically symmetric black hole. In this manner, we calculate the modified Hawking temperature and the other deformed thermal state quantities, namely, entropy, heat capacity, Helmholtz free energy and pressure. Finally, we also investigate the black hole evaporation process in such a context.

Hidden-charm pentaquark-like PψsΛ(4459)0 and PψsΛ(4338) resonances are studied in a constituent quark model as molecular meson-baryon structures. Such states are found in the JP(I)=12−(0) channel with masses and widths compatible with the experimental measurements in a coupled-channels calculation with all the parameters constrained from previous studies. Other candidates are explored in the JP=12−, 32− and 52− channels in the charm and bottom sectors, with isospins 0 (PψsΛ and PϒsΛ) and 1 (PψsΣ and PϒsΣ). Additionally, the formalism is extended to study the PψssN (PϒssN) pentaquarks, where eight candidates are predicted as D¯sΞc molecules in I=12, with JP=12−, 32− and 52− for the charm sector and nine candidates as BsΞb for the bottom one.

This Letter presents a search for direct production of charginos and neutralinos via electroweak interactions. The results are based on data from proton-proton collisions at a center-of-mass energy of 13 TeV collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb − 1 . The search considers final states with large missing transverse momentum and pairs of hadronically decaying bosons W W , W Z , and W H , where H is the Higgs boson. These bosons are identified using novel algorithms. No significant excess of events is observed relative to the expectations from the standard model. Limits at the 95% confidence level are placed on the cross section for production of mass-degenerate wino-like supersymmetric particles χ ˜ 1 ± and χ ˜ 2 0 , and mass-degenerate higgsino-like supersymmetric particles χ ˜ 1 ± , χ ˜ 2 0 , and χ ˜ 3 0 . In the limit of a nearly-massless lightest supersymmetric particle χ ˜ 1 0 , wino-like particles with masses up to 870 and 960 GeV are excluded in the cases of χ ˜ 2 0 → Z χ ˜ 1 0 and χ ˜ 2 0 → H χ ˜ 1 0 , respectively, and…

Charged gauge boson production at hadron colliders is a fundamental benchmark for the extraction of electroweak parameters and the understanding of the proton structure. To enable precision phenomenology for this process, we compute the third-order (N3LO) QCD corrections to the rapidity distribution and charge asymmetry in W boson production and to the transverse mass distribution of its decay products. Our results display substantial QCD corrections in kinematic regions relevant for Tevatron and LHC measurements. We compare the numerical magnitude of the N3LO corrections with uncertainties from electroweak input parameters and illustrate their potential impact on the determination of the W boson mass.

We study the possible correspondence between 5-dimensional primordial black holes and massive 5-dimensional KK gravitons as dark matter candidate within the recently proposed dark dimension scenario that addresses the cosmological hierarchy problem. First, we show that in the local universe a population of 5-dimensional black holes with MBH∼7×1013g would be practically indistinguishable from a KK tower of dark gravitons with mDM∼50keV. Second, we connect the mass increase of 5-dimensional black holes and the related temperature decrease with the cooling of the tower of massive spin-2 KK excitations of the graviton. The dark gravitons are produced at a mass ∼1−50GeV and the bulk of their mass shifts down to roughly 1−100keV today. The cooling of the system proceeds via decay to lighter gravitons without losing much total mass density, resembling the intra-tower decays that characterize the cosmological evolution of the dynamical dark matter framework. We associate the intra-tower decays of the graviton gas with the black hole growth through accretion. We also discuss that the…

We extend the old formalism of cut-and-join operators in the theory of Hurwitz τ-functions to description of a wide family of KP-integrable skew Hurwitz τ-functions, which include, in particular, the newly discovered interpolating WLZZ models. Recently, the simplest of them was related to a superintegrable two-matrix model with two potentials and one external matrix field. Now we provide detailed proofs, and a generalization to a multi-matrix representation, and propose the β-deformation of the matrix model as well. The general interpolating WLZZ model is generated by a W-representation given by a sum of operators from a one-parametric commutative sub-family (a commutative subalgebra of w∞). Different commutative families are related by cut-and-join rotations. Two of these sub-families (‘vertical’ and ‘45-degree’) turn out to be nothing but the trigonometric and rational Calogero-Sutherland Hamiltonians, the ‘horizontal’ family is represented by simple derivatives. Other families require an additional analysis.

We search for an axion-like particle (ALP) a through the process ψ(3686)→π+π−J/ψ, J/ψ→γa, a→γγ in a data sample of (2.71±0.01)×109 ψ(3686) events collected by the BESIII detector. No significant ALP signal is observed over the expected background, and the upper limits on the branching fraction of the decay J/ψ→γa and the ALP-photon coupling constant gaγγ are set at 95% confidence level in the mass range of 0.165≤ma≤2.84GeV/c2. The limits on B(J/ψ→γa) range from 8.3×10−8 to 1.8×10−6 over the search region, and the constraints on the ALP-photon coupling are the most stringent to date for 0.165≤ma≤1.468GeV/c2.

We consider Drell–Yan lepton pairs produced in hadronic collisions. We present high-accuracy QCD predictions for the transverse-momentum (qT) distribution and fiducial cross sections in the small qT region. We resum to all perturbative orders the logarithmically enhanced contributions up to the next-to-next-to-next-to-next-to-leading logarithmic (N4LL) accuracy and we include the hard-virtual coefficient at the next-to-next-to-next-to-leading order (N3LO) (i.e. O(αS3)) with an approximation of the N4LO coefficients. The massive axial-vector and vector contributions up to three loops have also been consistently included. The resummed partonic cross section is convoluted with approximate N3LO parton distribution functions. We show numerical results at LHC energies of resummed qT distributions for Z/γ⁎,W± production and decay, including the W± and Z/γ⁎ ratio, estimating the corresponding uncertainties from missing higher orders corrections and from incomplete or missing perturbative information coefficients at N4LL and N4LO. Our resummed calculation has been encoded in the public…

Modular flavor symmetries provide us with a very compelling approach to the flavor problem. It has been argued that moduli values close to some special values like τ=i or τ=ω provide us with the best fits to data. We point out that the presence of hidden “matter” fields, needed to uplift symmetric AdS vacua, gives rise to a dynamical mechanism that leads to such values of τ.