The pion-bump structure in the $\gamma$-ray spectrum is a direct proof for the hadronic origin of the $\gamma$ rays, and thus the decisive evidence for the acceleration of hadronic cosmic rays in astrophysical objects. However, the identification of such a spectral feature is limited by the resolution and energy coverage of current $\gamma$-ray instruments. Furthermore, there are unavoidable bremsstrahlung emissions from secondary and primary electrons, which may dominate the $\gamma$-ray emission below the pion-bump. Thus, the study of this $\gamma$-ray emission component can provide unique information on the acceleration and confinement of high-energy particles. In this paper, we studied the predicted $\gamma$-ray spectrum assuming both hadronic or leptonic origin in mid-aged supernova remnants W44, we discuss the detection potential of future MeV missions on these emissions and possible implications.

The effect of dark matter (DM) on $f$-mode oscillations in DM admixed neutron stars (NSs) is investigated in a comprehensive analysis with particular attention to the role of the nuclear equation of state. Hadronic matter is modeled by the relativistic mean-field model and the DM model is based on the neutron decay anomaly. The nonradial $f$-mode oscillations for such DM admixed NSs are studied in a full general relativistic framework. We investigate the impact of DM, DM self-interaction, and DM fraction on the $f$-mode characteristics. We derive relations encoding the effect of DM on $f$-mode parameters. We then perform a systematic study by varying all the model parameters within their known uncertainty range and obtain a universal relation for the DM fraction based on the total mass of the star and DM self-interaction strength. We also perform a correlation study among model parameters, NS observables, and in particular, $f$-mode parameters. Finally, we check the $f$-mode universal relations for the case of DM admixed NSs and demonstrate the existence of a degeneracy between purely hadronic NSs and DM admixed NSs.

The essence of the memory burden effect is that a load of information carried by a system stabilizes it. This universal effect is especially prominent in systems with a high capacity of information storage, such as black holes and other objects with maximal microstate degeneracy, the entities universally referred to as “saturons.” The phenomenon has several implications. The memory burden effect suppresses a further decay of a black hole, the latest, after it has emitted about half of its initial mass. As a consequence, the light primordial black holes that previously were assumed to be fully evaporated are expected to be present as viable dark matter candidates. In the present paper, we deepen the understanding of the memory burden effect. We first identify various memory burden regimes in generic Hamiltonian systems and then establish a precise correspondence in solitons and in black holes. We make transparent, at a microscopic level, the fundamental differences between the stabilization by a quantum memory burden versus the stabilization by a long-range classical hair due to a spin or an electric charge. We identify certain new features of potential observational interest, such as the model-independent spread of the stabilized masses of initially degenerate primordial black holes.

Numerical reconstruction techniques are widely employed in the calculation of multiloop scattering amplitudes. In recent years, it has been observed that the rational functions in multiloop calculations greatly simplify under partial fractioning. In this article, we present a technique to reconstruct rational functions directly in partial-fractioned form, by evaluating the functions at special integer points chosen for their properties under a $p$-adic metric. As an application, we apply this technique to reconstruct the largest rational function in the integration-by-parts reduction of one of the rank-5 integrals appearing in two-loop five-point full-color massless amplitude calculations in quantum chromodynamics. The number of required numerical probes (per prime field) is found to be around 25 times smaller than in conventional techniques, and the obtained result is 130 times smaller. The reconstructed result displays signs of additional structure that could be used to further reduce its size and the number of required probes.

We compute the gravitational form factors (GFFs) and study their applications for the description of the mechanical properties such as the pressure, shear force distributions, and the mechanical radius of the proton from its light-front wave functions (LFWFs) based on basis light-front quantization (BLFQ). The LFWFs of the proton are given by the lowest eigenvector of a light-front effective Hamiltonian that incorporates a three-dimensional confining potential and a one-gluon exchange interaction with fixed coupling between the constituent quarks solved in the valence Fock sector. We find acceptable agreement between our BLFQ computations and the lattice QCD for the GFFs. Our $D$-term form factor also agrees well with the extracted data from the deeply virtual Compton scattering experiments at Jefferson Lab, and the results of different phenomenological models. The distributions of pressures and shear forces are similar to those from different models.

In this work, we systematically calculate transition magnetic moments, radiative decay widths, and axial-vector coupling constants of octet hidden-charm molecular pentaquark states with different flavor representations in constituent quark model. We discuss the relations between transition magnetic moments and decay widths for pentaquark states. For octet pentaquark states with the $8_{1f}$ and $8_{2f}$ flavor representations, decay widths of the processes $P_{\psi }|{\frac{3}{2}}^{-}{⟩}_{({\frac{1}{2}}^{+}\otimes 1^{-})}\to P_{\psi }|{\frac{1}{2}}^{-}{⟩}_{({\frac{1}{2}}^{+}\otimes 0^{-})}\gamma$ and $P_{\psi }|{\frac{1}{2}}^{-}{⟩}_{({\frac{1}{2}}^{+}\otimes 1^{-})}\to P_{\psi }|{\frac{1}{2}}^{-}{⟩}_{({\frac{1}{2}}^{+}\otimes 0^{-})}\gamma$ are quite close, and decay widths of the $P_{\psi }|{\frac{3}{2}}^{-}{⟩}_{({\frac{1}{2}}^{+}\otimes 1^{-})}\to P_{\psi }|{\frac{1}{2}}^{-}{⟩}_{({\frac{1}{2}}^{+}\otimes 1^{-})}\gamma$ process are close to zero, and we notice that the axial-vector coupling constants of the pentaquark states are generally smaller than that of the nucleon.

We study the nonleptonic decays of $B\to PP$ in the modified perturbative QCD approach, where $P$ stands for pseudoscalar mesons. Transverse momenta of partons and the Sudakov factor are included, which help to suppress the contributions of soft interactions. The wave function of the $B$ meson obtained from the relativistic potential model is used, and then the contributions in the infrared region cannot be suppressed completely. So a soft cutoff scale and soft form factors are introduced. The contributions with the scale higher than the soft cutoff scale are calculated with perturbative QCD, while the contributions lower than the cutoff scale are replaced by the soft form factors. To explain experimental data, we find that contributions of color-octet operators for the quark-antiquarks in the mesons in the final state need to be considered. The contributions of the color-octet operators are parametrized by a few parameters with the help of SU(3) flavor symmetry and symmetry breaking. These parameters for color-octet contributions are universal for all the nonleptonic decay modes of the $B$ meson, where the mesons in the final state belong to the same flavor SU(3) nonet. Both the branching ratios and $CP$ violations are studied. We find that the theoretical calculation can well explain the experimental data of $B$ factories.

We employ the entropic uncertainty relations and the quantum Fisher information to explore the formation of quark $t\overline{t}$ pairs at the Large Hadron Collider through the combination of $q\overline{q}$ pair and $gg$ pair initiated processes. A comprehensive analysis has been undertaken on the procedure of quark and gluon channel mixing in the production of top quark pairs $t\overline{t}$, encompassing the tightness of the entropic uncertainty inequalities and the maximum quantum Fisher information of the system.

It was previously shown that unlike the ratios $R_K^{\mu e}\equiv R_K\equiv \mathrm{\Gamma }(B\to K{\mu }^{+}{\mu }^{-})/\mathrm{\Gamma }(B\to K{e}^{+}{e}^{-})$ and $R_{K^{*}}^{\mu e}\equiv R_{K^{*}}\equiv \mathrm{\Gamma }(B\to K^{*}{\mu }^{+}{\mu }^{-})/\mathrm{\Gamma }(B\to K^{*}{e}^{+}{e}^{-})$, the ratios $R_K^{\tau \mu }$ and $R_{K^{*}}^{\tau \mu }$ can deviate from their Standard Model (SM) predictions even with universal new physics couplings. This observation highlights the critical need to identify and establish genuine lepton flavor universality violating (LFUV) observables in the $\tau -\mu$ sector. This work embarks on establishing genuine LFUV ratio observables in $B\to K\ell \ell$ and $B\to K^{*}\ell \ell$ decays through comprehensive analysis of their angular distributions. We find that like $R_{K^{*}}^{\tau \mu }$, the ratios $R_{A_{FB}}^{\tau \mu }$ and $R_{f_L}^{\tau \mu }$ do not qualify as genuine LFUV observables, whereas the ratios of all optimized observables in $B\to K^{*}\ell \ell$ decays within the $\tau -\mu$ sector definitively do. In the case of $B\to K\ell \ell$ decays, similar to $R_K^{\tau \mu }$, the ratio $R_{F_H}$ is influenced by mass effects and therefore cannot be considered a genuine LFUV observable in the $\tau -\mu$ sector. However, the ratio ${\mathrm{\Gamma }}_{\tau }(1-F_H^{\tau })/{\mathrm{\Gamma }}_{\mu }(1-F_H^{\mu })$ stands as the sole genuine LFUV observable in $B\to K\ell \ell$ decays. Furthermore, by making use of new physics Lorentz structures which provide a better fit to the current $b\to s\ell \ell$ data as compared to the SM, we demonstrate how the nongenuine LFUV ratios $R_{A_{FB}}^{\tau \mu }$ and $R_{f_L}^{\tau \mu }$ can be employed to distinguish between framework with solely universal lepton couplings and those with both universal and nonuniversal couplings.

Motivated by the long-standing discrepancy in lepton flavor universality ratios $R_D$ and $R_{D^{*}}$ we assess the status of scalar leptoquark states $R_2$, ${\tilde{R}}_2$ and $S_1$ which can in principle provide a desired enhancement of $\mathcal{B}(B\to D^{(*)}\tau \nu )$ in a minimal setup with two Yukawa couplings only. We consider unavoidable low-energy constraints, $Z$-pole measurements as well as high-$p_T$ constraints. After setting the mass of each leptoquark to 1.5 TeV we find that of all considered states only $S_1$ leptoquark, coupled to both chiralities of leptons and quarks, is still a completely viable solution while the scenario with $R_2$ is in growing tension with $\mathrm{\Gamma }(Z\to \tau \tau )$ and with the LHC constraints on the ditau tails at high-$p_T$. We comment on the future experimental tests of the $S_1$ scenario.

We consider two-dimensional $\mathcal{N}=(2,2)$ Yang-Mills theory with gauge group $\mathrm{SU}(N)$ in Euclidean signature compactified on a torus with thermal fermion boundary conditions imposed on one cycle. We perform nonperturbative lattice analyses of this theory for large $12\le N\le 20$. Although no holographic dual of this theory is yet known, we conduct numerical investigations to check for features similar to the two-dimensional $\mathcal{N}=(8,8)$ Yang–Mills theory, which has a well-defined gravity dual. We perform lattice field theory calculations to determine the phase diagram, observing a spatial deconfinement transition similar to the maximally supersymmetric case. However, the transition does not continue to low temperature, implying the absence of a topology-changing transition between black hole geometries in any holographic dual for this four-supercharge theory.

We study for the first time the production of charmonia in nuclear ultraperipheral and electron-ion collisions based on a rigorous Green function formalism. Such formalism allows to incorporate properly formation effects (color transparency), as well as the quantum coherence inherent in higher-twist shadowing corrections related to the $|Q\overline{Q}⟩$ Fock component of the photon. The leading twist gluon shadowing associated with multigluon photon fluctuations is also included within the same formalism. The later effect represents the dominant source of shadowing at midrapidities in the LHC kinematic region, while the reduced effect of quark shadowing leads to a significant modification of differential cross sections $d\sigma /dy$ at forward and/or backwards rapidities. Model calculations for $d\sigma /dy$ are in a good agreement with available ultraperipheral nuclear $Pb\text{−}Pb$ collisions data on coherent charmonium production at RHIC and the LHC. In addition, we also perform predictions for nuclear effects in the electroproduction of charmonia, which can be verified by new data from electron-ion colliders.

We adopt the effective Lagrangian approach to study the strong decays of the $1^{-}(0^{++})D^{*}{\overline{D}}^{*}$ molecular state [denoted as $T_{\psi 0}^a(4010)$ according to the LHCb naming convention] through triangle diagrams. The decay channels include the open-charm $D\overline{D}$, and the hidden-charm ${\eta }_c\pi$, $J/\psi \rho$, and ${\chi }_{c1}\pi$. The coupling between the $T_{\psi 0}^a(4010)$ and its constituents $D^{*}{\overline{D}}^{*}$ is obtained by solving for the residue of the scattering $T$-matrix at the pole. Our calculations yield a total width of few tens MeV for the $T_{\psi 0}^a(4010)$ state using three different form factors, with its main decay channels being ${\eta }_c\pi$ and ${\chi }_{c1}\pi$. The $X(4100)$ and $X(4050)$ have similar masses and widths, with both masses being close to the $D^{*}{\overline{D}}^{*}$ threshold. Additionally, their decay final states are consistent with those of the $T_{\psi 0}^a(4010)$. Therefore, it is likely that they represent the same state and both potentially correspond to the $T_{\psi 0}^a(4010)$. We suggest that future experiments focus on searching for the $T_{\psi 0}^a(4010)$ signal in the final states ${\eta }_c{\pi }^{-}$, ${\chi }_{c1}{\pi }^{-}$, and $D^0{D}^{-}$ of the $B^0\to {\eta }_c{\pi }^{-}{K}^{+}$, ${\chi }_{c1}{\pi }^{-}{K}^{+}$, and $D^0{D}^{-}{K}^{+}$ processes, respectively, as well as further investigating its resonance parameters with Flatté-like formula.

In this paper, we consider the Einstein-Maxwell-dilaton holographic model for light quarks with nonzero magnetic field and chemical potential. First, we study the phase diagrams in $T\text{−}\mu$ and $T\text{−}B$ planes. We observe inverse magnetic catalysis which is consistent with the lattice QCD results. We discuss the influence of the magnetic field and chemical potential on the location of the critical end point (CEP). It is found that the magnetic field increases the critical ${\mu }_{CEP}$ of the CEP in the $T\text{−}\mu$ plane and the chemical potential increases the critical $B_{CEP}$ of the CEP in the $T\text{−}B$ plane. Second, we discuss the equations of state (EOS) with nonzero magnetic field and chemical potential. We observe that the EOS near the phase transition temperature are nonmonotonic. Then we study the energy loss with a nonzero magnetic field and chemical potential. It is found that the drag force of the heavy quark and jet quenching parameter $\widehat{q}$ show an enhancement near the phase transition temperature. The peak values of drag force and $\widehat{q}$ are pushed toward lower temperature with increasing $B$ or $\mu$. This phenomenon is consistent with the phase transition temperature decrease with increasing $B$ or $\mu$ in this holographic model. Moreover, we find that the heavy quark may lose more energy when it is perpendicular to a magnetic field, which is consistent with the results of the jet quenching parameter.

Recent developments in anti–de Sitter holography point towards the association of an infinite class of covariant objects, the simplest one being codimension-one extremal volumes, with quantum computational complexity in the microscopic description. One of the defining features of these gravitational complexity proposals is describing the persistent growth of black hole interior in classical gravity. It is tempting to assume that the gravitational complexity proposals apply also to gravity outside their native anti–de Sitter setting in which case they may reveal new truths about these cases with much less understood microscopics. Recent first steps in this direction in de Sitter static patch demonstrated a very different behavior from anti–de Sitter holography deemed hyperfast growth; diverging complexification rate after a finite time. We show that this feature is not a necessity and among gravitational complexity proposals there are ones, that predict linear or exponential late-time growth behaviors for complexity in de Sitter static patches persisting classically forever.

The evolution of 1 vortices when their massive bound mode is excited is investigated in detail (both analytically and numerically) in the Abelian-Higgs model for different ranges of the self-coupling constant. The dependence of the spectrum of the 1 vortex fluctuation operator on the model parameter is discussed initially. A perturbative approach is employed to study the radiation emission in both the scalar and the vector channels. Our findings reveal that the oscillating initial configuration of the 1 vortex radiates at a frequency twice that of the internal mode. Through energy conservation considerations, we derive the decay law of the massive mode. Finally, these analytical results are compared with numerical simulations in field theory.

In this article, we investigate a coupled phantom dark-energy cosmological model in which the coupling term between a phantom scalar field with an exponential potential and a pressureless dark-matter fluid is motivated by the warm inflationary paradigm. Using methods of qualitative analysis of dynamical systems, complemented by numerical solutions of the evolution equations, we study the late-time behavior of our model. We show that contrary to the uncoupled scenario, the coupled phantom model admits accelerated scaling solutions. However, they do not correspond to a final state of the Universe’s evolution and, therefore, cannot be used to solve the cosmological coincidence problem. Furthermore, we show that, for certain coupling parameter values, the total equation-of-state parameter’s asymptotic behavior is significantly changed when compared to the uncoupled scenario, allowing for solutions less phantom even for steeper potentials of the phantom scalar field.

Primordial black holes (PBHs) formed in the early Universe are well-motivated dark matter (DM) candidates over a wide range of masses. These PBHs could emit detectable signals in the form of photons, electrons, and neutrinos through Hawking radiation. We consider the null observations of astrophysical ${\overline{\nu }}_e$ flux from several neutrino detectors and set new constraints on the PBHs as the dominant DM component to be above $6.4\times {10}^{15}\mathrm{g}$. We also estimate the expected constraints with JUNO for the prospects in the near future. Lastly, we note that the diffuse supernova neutrino background (DSNB) is an unavoidable isotropic background. We thus estimate the sensitivity floor for PBH parameter space due to the DSNB and show that it is challenging for neutrino detectors to identify PBHs as they constitute 100% of the DM above a mass of $9\times {10}^{15}\mathrm{g}$.

We propose a simple fit function, $L_{{\nu }_i}(t)=C{t}^{-\alpha }{e}^{-(t/\tau {)}^n}$, to parametrize the luminosities of neutrinos and antineutrinos of all flavors during the protoneutron star (PNS) cooling phase at postbounce times $t\gtrsim 1\mathrm{s}$. This fit is based on results from a set of neutrino-hydrodynamics simulations of core-collapse supernovae in spherical symmetry. The simulations were performed with an energy-dependent transport for six neutrino species and took into account the effects of convection and muons in the dense and hot PNS interior. We provide values of the fit parameters $C$, $\alpha$, $\tau$, and $n$ for different neutron star masses and equations of state as well as correlations between these fit parameters. Our functional description is useful for analytic supernova modeling, for characterizing the neutrino light curves in large underground neutrino detectors, and as a tool to extract information from measured signals on the mass and equation of state of the PNS and on secondary signal components on top of the PNS’s neutrino emission.

We develop a method to calculate helicity amplitudes of an arbitrary tree-level process in the Feynman-diagram (FD) gauge for an arbitrary gauge model with madgraph5_amc@nlo. We start from the ’t Hooft–Feynman gauge Lagrangian in feynrules and generate scattering amplitudes by identifying the Goldstone boson as the 5th component of each weak boson. All the vertices of the 5-component weak bosons are then created automatically by assembling the relevant weak boson and Goldstone boson vertices in the Feynman gauge. The 5-component weak boson vertices are then connected by the $5\times 5$ matrix propagator in the FD gauge. As a demonstration of the method we calculate the cross section for the process ${\mu }^{-}{\mu }^{+}\to {\nu }_{\mu }{\overline{\nu }}_{\mu }t\overline{t}H$ with complex top Yukawa coupling, which can be obtained by adding a gauge invariant dimension-6 operator to the Standard Model (SM) Lagrangian. The FD gauge and the unitary (U) gauge amplitudes give exactly the same cross section, and subtle gauge theory cancellation among diagrams in the U gauge at high energies is absent in the FD gauge, as has been observed for various SM processes. In addition, we find that the total cross sections at high energies are dominated by a single, or a set of nonvanishing Feynman amplitudes with the higher dimensional vertices in the FD gauge.