We have evaluated the strong decays of the $K_0^{*}(1950)$ and $K_0^{*}(2130)$ within the ${}^3{P}_0$ model by employing the meson wave functions from the relativized quark model. By comparing with the experimental measurements, the $K_0^{*}(2130)$ could be assigned as $K_0^{*}(3^3{P}_0)$, while the $K_0^{*}(1950)$ is difficult to be explained as the $q\overline{q}$ meson. We also predict that the $K_0^{*}(2^3{P}_0)$ state has a mass of about 1811 MeV and a width of about 656 MeV, while the $K_0^{*}(4^3{P}_0)$ state has a mass of about 2404 MeV and a width of about 180 MeV.

In this paper we suggest a new approach to the structure of the soft Pomeron: based on the $t$-channel unitarity, we expressed the exchange of the soft Pomeron through the interaction of the dipole of small size of the order of $1/Q_s(Y)$ [$Q_s(Y)$ is the saturation momentum] with the hadrons. Therefore, it is shown that the typical distances in soft processes are small $r\sim 1/Q_s(\frac{1}{2}Y)$, where $Y=lns$. The saturation momentum, which determines the energy dependence of the scattering amplitude, is proportional to $Q_s^2(\frac{1}{2}Y)\propto \exp (\frac{1}{2}\lambda Y)$, with $\lambda \approx 0.2$, and this behavior is in perfect agreement with the phenomenological Donnachie-Landshoff Pomeron. We demonstrate that the saturation models could describe the experimental data for ${\sigma }_{\mathrm{tot}},{\sigma }_{el},{\sigma }_{\mathrm{diff}}$ and $B_{el}$. Hence, our approach is a good first approximation to start discussion of the soft processes in the color glass condensate approach on the solid theoretical basis.

The discrepancies between the measurements of rare (semi)leptonic $B$ decays and the corresponding Standard Model predictions point convincingly toward the existence of new physics for which a heavy neutral gauge boson ($Z^{\prime }$) is a prime candidate. However, the effect of the mixing of the $Z^{\prime }$ with the SM $Z$, even though it cannot be avoided by any symmetry, is usually assumed to be small and thus neglected in phenomenological analyses. In this paper we point out that a mixing of the naturally expected size leads to lepton flavor universal contributions, providing a very good fit to $B$ data. Furthermore, the global electroweak fit is affected by $Z-Z^{\prime }$ mixing where the tension in the $W$ mass, recently confirmed and strengthened by the CDF measurement, prefers a nonzero value of it. We find that a $Z^{\prime }$ boson with a mass between $\approx 1–5\mathrm{TeV}$ can provide a unified explanations of the $B$ anomalies and the $W$ mass. This strongly suggest that the breaking of the new gauge symmetry giving raise to the $Z^{\prime }$ boson is linked to electroweak symmetry breaking with intriguing consequences for model building.

We present a measurement of the density of GeV muons in near-vertical air showers using three years of data recorded by the IceTop array at the South Pole. Depending on the shower size, the muon densities have been measured at lateral distances between 200 and 1000 m. From these lateral distributions, we derive the muon densities as functions of energy at reference distances of 600 and 800 m for primary energies between 2.5 and 40 PeV and between 9 and 120 PeV, respectively. The muon densities are determined using, as a baseline, the hadronic interaction model Sibyll 2.1 together with various composition models. The measurements are consistent with the predicted muon densities within these baseline interaction and composition models. The measured muon densities have also been compared to simulations using the post-LHC models EPOS-LHC and QGSJet-II.04. The result of this comparison is that the post-LHC models together with any given composition model yield higher muon densities than observed. This is in contrast to the observations above 1 EeV where all model simulations yield for any mass composition lower muon densities than the measured ones. The post-LHC models in general feature higher muon densities so that the agreement with experimental data at the highest energies is improved but the muon densities are not correct in the energy range between 2.5 and about 100 PeV.

Considering a six-dimensional geometry orbifolded on $S^1/Z_2\times S^1/Z_2$ with quarks and leptons localized on orthogonal branes, we show that the construction admits observable $n-\overline{n}$ oscillation while naturally suppressing the proton decay rates. Consistent with other low-energy observables, the model also accommodates baryogenesis at $\mathcal{O}(10\mathrm{TeV})$ scale.

We study the $T\overline{T}$ deformation on multiquantum mechanical systems. By introducing dynamical coordinate transformation, we reformulate the one-dimensional $T\overline{T}$ deformation of generic quantum mechanical systems, which is consistent with the previous proposal in the literature. We further study the thermo-field-double state under the $T\overline{T}$ deformation on these systems, which include the conformal quantum mechanical system, the Sachdev-Ye-Kitaev model, and the model satisfying the eigenstate thermalization hypothesis. We find common regenesis phenomena in which the signal injected into one local system can regenerate from the other local system. From the ${\mathrm{AdS}}_2/{\mathrm{CFT}}_1$ perspective, we study the deformation of Jackiw-Teitelboim gravity governed by Schwarzian action and find that these regenesis phenomena are realized by exchanging boundaries graviton via the nonlocal $T\overline{T}$ coupling.

This paper is part of a series of papers exploring the renormalization of field theories coupled to gravity using the effective field theory framework. In previous works, we studied the universality of the electric charge and the two-loops beta function in the Einstein-QED system. Now, we use this framework to study the non-Abelian gauge theory with fermions coupled to gravity. We show that even though some of the counterterms are dependent on the gravitational coupling, the renormalized coupling constant, and therefore the beta function, do not receive any gravitational correction at one-loop order. Also, we explicitly show that, at this order, the Slavnov-Taylor identities are respected. Finally, we end the paper by putting into perspective the results of the present and the past papers.

$f(Q)$ gravity is an extension of the symmetric teleparallel equivalent to general relativity. We demonstrate the Hamiltonian analysis of $f(Q)$ gravity with fixing the coincident gauge condition. Using the standard Dirac-Bergmann algorithm, we show that $f(Q)$ gravity has 8 physical degrees of freedom. This result reflects that the diffeomorphism symmetry of $f(Q)$ gravity is completely broken due to the gauge fixing. Moreover, in terms of the perturbations, we discuss the possible mode decomposition of these degrees of freedom.

Among the modified gravitational theories, the ghost-free Gauss-Bonnet (GFGB) theory of gravity has been considered from the viewpoint of cosmology. The best way to check its applicability could be to elicit observable predicts which give guidelines or limitations on the theory, which could be contrasted with the actual observations. In the present study, we derive consistent field equations for GFGB and by applying the equations to a spherically symmetric space-time, we obtain new spherically symmetric black hole (BH) solutions. We study the physical properties of these BH solutions and show that the obtained space-time possesses multihorizons and the Gauss-Bonnet invariants in the space-time are not trivial. We also investigate the thermodynamical quantities related to these BH solutions and we show that these quantities are consistent with what is known in the previous works. Finally, we study the geodesic equations of these solutions which give the photon spheres and we find the perihelion shift for weak GFGB. In addition, we calculate the first-order GFGB perturbations in the Schwarzschild solution and new BH solutions and show that we improve and extend existing results in the past literature on the spherically symmetric solutions.

This paper focuses on the semiclassical behavior of the spinfoam quantum gravity in four dimensions. There has been long-standing confusion, known as the flatness problem, about whether the curved geometry exists in the semiclassical regime of the spinfoam amplitude. The confusion is resolved by the present work. By numerical computations, we explicitly find curved Regge geometries that contribute dominantly to the large-$j$ Lorentzian Engle-Pereira-Rovelli-Livine (EPRL) spinfoam amplitudes on triangulations. These curved geometries are with small deficit angles and relate to the complex critical points of the amplitude. The dominant contribution from the curved geometry to the spinfoam amplitude is proportional to $e^{i\mathcal{I}}$, where $\mathcal{I}$ is the Regge action of the geometry plus corrections of higher order in curvature. As a result, in the semiclassical regime, the spinfoam amplitude reduces to an integral over Regge geometries weighted by $e^{i\mathcal{I}}$, where $\mathcal{I}$ is the Regge action plus corrections of higher order in curvature. As a by-product, our result also provides a mechanism to relax the cosine problem in the spinfoam model. Our results provide important evidence supporting the semiclassical consistency of the spinfoam quantum gravity.

Postinflationary reheating is a widely discussed mechanism for nonthermal production of dark matter (DM). In this scenario the momentum distribution of the produced DM particles is usually taken to be the one obtained at reheating, redshifted at later times due to the expansion of the Universe. However, since in such a scenario both the DM and the standard model (SM) fields couple to the inflaton, the DM particles necessarily undergo self-scatterings, as well as elastic and inelastic scattering reactions with the SM bath, all of which proceed through $s$-channel or $t$-channel inflaton exchange. We compute the momentum distribution of the DM particles including the effect of these scatterings, and find that the distributions can be significantly altered, even though DM remains nonthermal throughout the cosmological evolution. We observe that if the inflaton dominantly couples to the SM Higgs boson through a renormalizable interaction, then reheating temperatures and inflaton masses at the TeV scale lead to a large effect from the scattering processes, with the DM-inflaton coupling constrained by the DM density. The scattering effects are found to be sensitive to the duration of the reheating process—larger the duration, more momentum modes are filled at reheating, leading to an enhanced scattering probability. We also obtain the free-streaming length of such DM using the resulting nonthermal momentum distribution, which can be used to estimate the implications of the Lyman-$\alpha$ constraints on the DM mass. It is observed that in the scenarios considered, including the scattering effects can reduce the DM average velocity at matter-radiation equality, and its free-streaming length, by up to a factor of 40, thereby making the constraints on light DM produced in inflaton decay significantly weaker.

The effective approach in loop quantum cosmology (LQC) has provided means to obtain predictions for observable quantities in LQC models. While an effective dynamics in LQC has been extensively considered in different scenarios, a robust demonstration of the validity of effective descriptions for the perturbative level still requires further attention. The consistency of the description adopted in most approaches requires the assumption of a test field approximation, which is limited to the cases in which the backreaction of the particles gravitationally produced can be safely neglected. Within the framework of LQC, some of the main approaches to quantize the linear perturbations are the dressed metric, the hybrid approaches and the closed or deformed algebra approach. Here, we analyze the consistency of the test field assumption in these frameworks by computing the energy density stored in the particles gravitationally produced compared to the background energy density. This analysis ultimately provides us with a consistency test of the effective descriptions of LQC.

Axionlike particles (ALPs) are promising dark matter candidates. They are typically described by a classical field, motivated by large phase space occupation numbers. Here we show that such a description is accompanied by a quantum effect: squeezing due to gravitational self-interactions. For a typical QCD axion today, the onset of squeezing is reached on $\mu \mathrm{s}$ scales and grows over millennia. Thus within the usual models based on the classical Schrödinger-Poisson equation, a type of Gross-Pitaevskii equation, any viable ALP is nonclassical. We also show that squeezing may be relevant on the scales of other self-gravitating systems such as galactic haloes, or solitonic cores. Conversely, our results highlight the incompleteness and limitations of the classical single field description of ALPs.

In the mixed dark matter scenarios consisting of primordial black holes (PBHs) and weakly interacting massive particles (WIMPs), WIMPs can be accreted onto PBHs to form ultracompact minihalos (UCMHs) with a density spike in the early universe. Compared with the classical dark matter halo, UCMHs are formed earlier and have a higher density of center. Since the annihilation rate is proportional to the squared number density of WIMPs, it is expected that WIMPs annihilation within UCMHs is enhanced and has influences on the early universe. Between the time of recombination and matter-radiation equality, the energy released from WIMPs annihilation within UCMHs is injected into the Universe resulting in cosmic microwave background $y$-type distortion. We investigate these effects and derive the upper limits on the abundance of PBHs taking advantage of the observational results of a far infrared absolute spectrophotometer (FIRAS). We find that for the WIMPs mass range $1\le m_{\chi }\le 1000\mathrm{GeV}$, the upper limits on the abundance of PBHs are $5\times {10}^{-3}\le {\mathrm{\Omega }}_{\mathrm{PBH}}\le 5\times {10}^{-2}$.

Instead of parametrizing the pressure-density relation of a neutron star (NS), one can parametrize its macroscopic properties such as mass ($M$), radius ($R$), and dimensionless tidal deformability ($\mathrm{\Lambda }$) to infer the equation of state (EOS) combining electromagnetic and gravitational wave (GW) observations. We present a new method to parametrize $R(M)$ and $\mathrm{\Lambda }(M)$ relations, which approximates the candidate EOSs with accuracy better than 5% for all masses and spans a broad region of the $M-R-\mathrm{\Lambda }$ plane. Using this method we combine the $M-\mathrm{\Lambda }$ measurement from GW170817 and GW190425, and simultaneous $M-R$ measurement of pulsars PSR $\mathrm{J}0030+0451$ and PSR $\mathrm{J}0740+6620$ to place joint constraints on NS properties. At 90% confidence, we infer $R_{1.4}=12.05_{-0.87}^{+0.98}\mathrm{km}$ and ${\mathrm{\Lambda }}_{1.4}=372_{-150}^{+220}$ for a $1.4M_{\odot }$ NS, and $R_{2.08}=12.65_{-1.46}^{+1.36}\mathrm{km}$ for a $2.08M_{\odot }$ NS. Furthermore, we use the inferred values of the maximum mass of a nonrotating NS $M_{\max }=2.52_{-0.29}^{+0.33}{M}_{\odot }$ to investigate the nature of the secondary objects in three potential neutron star–black hole merger (NSBH) systems.

The fast flavor instability (FFI) is expected to be ubiquitous in core-collapse supernovae and neutron star mergers. It rapidly shuffles neutrino flavor in a way that could impact the explosion mechanism, neutrino signals, mass outflows, and nucleosynthesis. The variety of initial conditions and simulation methods employed in simulations of the FFI prevent an apples-to-apples comparison of the results. We simulate a standardized test problem using five independent codes and verify that they are all faithfully simulating the underlying quantum kinetic equations under the assumptions of axial symmetry and homogeneity in two directions. We quantify the amount of numerical error in each method and demonstrate that each method is superior in at least one metric of this error. We make the results publicly available to serve as a benchmark.

Many compelling models predict dark matter coupling to the electromagnetic current through higher multipole interactions, while remaining electrically neutral. Different multipole couplings have been studied, among them anapole moment, electric and magnetic dipole moments, and millicharge. This study sets limits on the couplings for these photon-mediated interactions using nonrelativistic contact operators in an effective field theory framework. Using data from the PICO-60 bubble chamber leading limits for dark matter masses between 2.7 and $24\mathrm{GeV}/{\mathrm{c}}^2$ and above $265\mathrm{GeV}/{\mathrm{c}}^2$ (anapole moment), 2.7 and $11.7\mathrm{GeV}/{\mathrm{c}}^2$ (electric moment), 3 and $9.5\mathrm{GeV}/{\mathrm{c}}^2$ (magnetic moment), and 2.7 and $12\mathrm{GeV}/{\mathrm{c}}^2$ (millicharged) are reported for the coupling of these photon-mediated dark matter-nucleus interactions. The detector was filled with 52 kg of ${\mathrm{C}}_3{\mathrm{F}}_8$ operating at thermodynamic thresholds of 2.45 keV and 3.29 keV, reaching exposures of $1404\mathrm{kg}\text{−}\mathrm{day}$ and $1167\mathrm{kg}\text{−}\mathrm{day}$, respectively.

We derive multicomponent relativistic second-order dissipative fluid dynamics from the Boltzmann equations for a reactive mixture of $N_{\mathrm{spec}}$ particle species with $N_q$ intrinsic quantum numbers (e.g., electric charge, baryon number, and strangeness) using the method of moments. We obtain the continuity equations for multiple conserved charges as well as the conservation equations for the total energy and momentum in the single-fluid approximation. These $4+N_q$ conservation laws are closed by deriving the second-order equations of motion for the dissipative quantities in the $(10+4N_q)$-moment approximation. The resulting fluid-dynamical equations are formally similar to those of a single-component system, but feature different thermodynamic relations and transport coefficients. We derive general relations for all transport coefficients and compute them explicitly in the ultrarelativistic limit.