We consider $\mathcal{N}=2$ supersymmetric SU(2) gauge theory with $N_f=4$ massive hypermultiplets. The duality group of this theory contains transformations acting on the UV coupling ${\tau }_{\mathrm{UV}}$ as well as on the running coupling $\tau$. We establish that subgroups of the duality group act separately on ${\tau }_{\mathrm{UV}}$ and $\tau$, while a larger group acts simultaneously on ${\tau }_{\mathrm{UV}}$ and $\tau$. For special choices of the masses, we find that the duality groups can be identified with congruence subgroups of $\mathrm{SL}(2,\mathbb{Z})$. We demonstrate that in such cases, the order parameters are instances of bimodular forms with arguments $\tau$ and ${\tau }_{\mathrm{UV}}$. Since the UV duality group of the theory contains the triality group of outer automorphisms of the flavor symmetry SO(8), the duality action gives rise to an orbit of mass configurations. Consequently, the corresponding order parameters combine to vector-valued bimodular forms with $\mathrm{SL}(2,\mathbb{Z})$ acting simultaneously on the two couplings.

We study the process of fully nonlinear dynamical scalarization starting from a charged black hole or a naked singularity in asymptotically flat spacetime in the Einstein-Maxwell-dilaton theory. Initially, the dilaton field is negligible compared to the gravitational and the Maxwell field. Then the dilaton field experiences an immediate growth, later it oscillates with damping amplitude and finally settles down to a finite value. For a hairy black hole that develops from an original Reissner-Nordström black hole, since the dilaton oscillation and decay are almost independent of the coupling parameter, unlike the anti–de Sitter spacetime it is not easy to distinguish the resulting hairy black hole from the original asymptotically flat charged hole. For a hairy black hole evolves from an original naked singularity, the resulting hairy black hole has rich structures. In the scalarization process, the naked singularity is soon enveloped by one outer horizon, then another horizon is developed and in the end, a stable hairy black hole forms and two horizons degenerate into one protecting the singularity. The hairy black hole mass saturates exponentially in the scalarization.

We investigate the superradiant (in)stability of the extremal multicharge static black holes in the STU supergravity model, which reduce to the Reissner-Nordström (RN) black hole when all the charges are equal. We first show that the frequency of quasibound states is necessarily complex and obtain the corresponding superradiant condition. We then study the effective potential of the Schrödinger-like equation associated with the radial function of the charged scalar field. We find that trapping-well configurations can emerge with either a single peak or double peaks. We numerically obtain the corresponding unstable quasibound states, organized under the overtone number, as well as how the charged black holes deviate from the RN black hole. We find that the STU black holes are superradiantly unstable as long as not all the charges are equal, indicating that the superradiant stability of the extremal RN black hole is a fine-tuning result in the framework of the STU supergravity model.

In Quantum Chromodynamics, the Schwinger mechanism endows the gluons with an effective mass through the dynamical formation of massless bound-state poles that are longitudinally coupled. The presence of these poles affects profoundly the infrared properties of the interaction vertices, inducing crucial modifications to their fundamental Ward identities. Within this general framework, we present a detailed derivation of the non-Abelian Ward identity obeyed by the pole-free part of the three-gluon vertex in the soft-gluon limit, and determine the smoking-gun displacement that the onset of the Schwinger mechanism produces to the standard result. Quite importantly, the quantity that describes this distinctive feature coincides formally with the bound-state wave function that controls the massless pole formation. Consequently, this signal may be computed in two independent ways: by solving an approximate version of the pertinent Bethe-Salpeter integral equation, or by appropriately combining the elements that enter in the aforementioned Ward identity. For the implementation of both methods we employ two- and three-point correlation functions obtained from recent lattice simulations, and a partial derivative of the ghost-gluon kernel, which is computed from the corresponding Schwinger-Dyson equation. Our analysis reveals an excellent coincidence between the results obtained through either method, providing a highly nontrivial self-consistency check for the entire approach. When compared to the null hypothesis, where the Schwinger mechanism is assumed to be inactive, the statistical significance of the resulting signal is estimated to be 3 standard deviations.

We reconsider the status of the so-called second clock effect in Weyl gauge theories of gravity, which are invariant both under local Poincaré transformations and local changes of scale. In particular, we revisit and extend our previous demonstration that the second clock effect does not occur in such theories, in order both to clarify our argument and confirm our original findings in response to recent counterclaims in the literature.

In this short note we study null dimensional reduction of M5-brane covariant action. We analyze longitudinal dimensional reduction that leads to nonrelativistic D4-brane and transverse reduction that leads to NS5-brane in nonrelativistic string theory.

In this work, we consider a massive gauge boson field in ${\mathrm{AdS}}_5$ dual to odd glueball states with twist-5 operator in 4D Minkowski spacetime. Introducing an IR cutoff, we break the conformal symmetry of the boundary theory allowing us to calculate the glueball masses with odd spins using Dirichlet and Neumann boundary conditions. Then, from these masses, we construct the corresponding Regge trajectories associated with the odderon. Our results are compatible with the ones in the literature.

The $S$-matrix formulation indicates that a consistent embedding of the de Sitter state in quantum gravity is possible exclusively as an excited quantum state constructed on top of a valid $S$-matrix vacuum such as the Minkowski vacuum. In the present paper we offer such a construction of the de Sitter state in the form of a coherent state of gravitons. Unlike previous realizations of this idea, we focus on BRST invariance as the guiding principle for physicality. In order to establish the universal rules of gauge consistency, we study the BRST-invariant construction of coherent states created by classical and quantum sources in QED and in linearized gravity. Introduction of $N$ copies of scalar matter coupled to gravity allows us to take a special double scaling limit, a so-called species limit, in which our construction of the de Sitter state becomes exact. In this limit, the irrelevant quantum gravitational effects vanish, whereas the collective phenomena, such as Gibbons-Hawking radiation, are calculable.

We develop a general formalism for treating radiative degrees of freedom near ${\mathcal{I}}^{+}$ in theories with an arbitrary Ricci-flat internal space. These radiative modes are encoded in a generalized news tensor which decomposes into gravitational, electromagnetic, and scalar components. We find a preferred gauge which simplifies the asymptotic analysis of the full nonlinear Einstein equations and makes the asymptotic symmetry group transparent. This asymptotic symmetry group extends the Bondi–Metzner–Sachs (BMS) group to include angle-dependent isometries of the internal space. We apply this formalism to study memory effects, which are expected to be observed in future experiments, that arise from bursts of higher-dimensional gravitational radiation. We outline how measurements made by gravitational wave observatories might probe properties of the compact extra dimensions.

One reconsiders strong lensing by the naked singularity that enters the Fisher/Janis-Newman-Winicour (F/JNW) scalar-tensor spacetime, characterized by a mass $m$ and a scalar parameter $b$. One mainly focuses on the strongly scalarized case where the bending of light experiments a maximum value, resulting in the formation of a $b$ dependent caustic cone. One numerically determines the caustic cone’s aperture $b$ dependence profile, and shows that this cone results in a flare sequence if the singularity is orbited by a star having an orbital inclination that satisfies a simple $b$ dependent condition. Such flare sequences qualitatively distinguish such F/JNW spacetimes from the usual black hole case. One then investigates the scenario that replaces the black hole located at the center of our Galaxy by a strongly scalarized F/JNW singularity having the same mass $m$. One shows that if a sequence of flares associated to the motion of a star orbiting not too far from the singularity (for the usual perihelion precession to have measurable effects) is detected, this would not only be an argument in favor of the presence of a (strongly scalarized) naked singularity with respect to the usual black hole assumption, but it could also return constraints on $b$ and determine the star’s orbital parameters, even if the star can not be monitored directly.

We present the detailed analyses of a model of loop quantum Schwarzschild interior coupled to a massless scalar field and extend the results in our previous rapid communication [C. Zhang, Y. Ma, S. Song, and X. Zhang, Loop quantum Schwarzschild interior and black hole remnant, Phys. Rev. D 102, 041502 (2020)] to more general schemes. It is shown that the spectrum of the black hole mass is discrete and does not contain zero. This supports the existence of a black hole remnant after Hawking evaporation due to loop quantum gravity effects. Besides to show the existence of a nonvanishing minimal black hole mass in the vacuum case, the quantum dynamics for the nonvacuum case is also solved and compared with the effective one.

In this paper, we extend the mimetic gravity to the multifield setup with a curved field space manifold. The multifield mimetic scenario is realized via the singular limit of the conformal transformation between the auxiliary and the physical metrics. We look for the cosmological implications of the setup where it is shown that at the background level the mimetic energy density mimics the roles of dark matter. At the perturbation level, the scalar field perturbations are decomposed into the tangential and normal components with respect to the background field space trajectory. The adiabatic perturbation tangential to the background trajectory is frozen while the entropy mode perpendicular to the background trajectory propagates with the speed of unity. Whether or not the entropy perturbation is healthy directly depends on the signature of the field-space metric. We perform the full nonlinear Hamiltonian analysis of the system with the curved field space manifold and calculate the physical degrees of freedom verifying that the system is free from the Ostrogradsky-type ghost.

We revisit the mechanism of helical magnetogenesis during inflation with a parity-violating interaction using the formalism of stochastic inflation. One of the polarizations of the gauge field undergoes tachyonic growth, leading to the generation of helical magnetic fields. We obtain the Langevin equations associated with the electromagnetic fields, which are in the form of Ornstein-Uhlenbeck stochastic differential equations. Consequently, the tachyonic growth of the helical magnetic fields is balanced by a mean-reverting process of stochastic dynamics such that the magnetic fields settle down to an equilibrium state with the amplitude smaller than what is obtained in the absence of the stochastic noises. Working in the parameter space of the model where both the backreaction and the strong coupling problems are under control, the model does not provide a large enough seed to be amplified by the galactic dynamo as the source of the magnetic fields observed on cosmological scales.

We investigate the $D_s^{+}\to K^{+}{K}^{-}{\pi }^{+}$ decay theoretically with the final state interactions, which is based on the chiral unitary approach and takes into account the external and internal $W$-emission mechanisms at the quark level. Only considering three resonances contributions, the $f_0(980)$ in $S$-wave, the ${\overline{K}}^{*}(892{)}^0$ and $\varphi (1020)$ in $P$-wave, one can make a good description of the recent experimental data from the BESIII Collaboration, where the contribution from the $S$-wave is found to be small. Besides, we also make a calculation of the corresponding branching fractions, which are consistent with the results of the BESIII Collaboration and Particle Data Group.

We investigate the strong acceleration properties of the radiation reaction force and identify a new and promising limiting acceleration feature in the Eliezer-Ford-O’Connell model; in the strong field regime, for many field configurations, we find an upper limit to acceleration resulting in a bound to the rate of radiation emission. If this model applies, strongly accelerated particles are losing energy at a much slower pace than predicted by the usual radiation reaction benchmark, the Landau-Lifshitz equation, which certainly cannot be used in this regime. We explore examples involving various “constant” electromagnetic field configurations and study particle motion in a light plane wave as well as in a material medium.

In this paper, we present a model which attempts to unify a new dark sector force with a local $SU(3)$ flavor symmetry. Dark matter (DM) and its potential interactions with the Standard Model (SM) continue to present a rich framework for model building. In the case of thermal DM of a mass between a few MeV and a few GeV, a compelling and much-explored framework is that of a dark photon/vector portal, which posits a new $U(1)$ “dark photon” which only couples to the SM via small kinetic mixing (KM) with the SM hypercharge. This mixing can be mediated at the one-loop level by portal matter (PM) fields which are charged under both the dark $U(1)$ and the SM gauge group. In earlier work, one of the authors has noted that models with appropriate portal matter content to produce finite and calculable kinetic mixing can arise from nonminimal dark sectors, in which the dark $U(1)$ is a subgroup of a larger gauge symmetry under which SM particles might have nontrivial representations. We expand on this idea here by constructing a model in which in which the dark $U(1)$ is unified with another popular extension to the SM gauge group, a local $SU(3)$ flavor symmetry. The full dark/flavor symmetry group is $SU(4{)}_F\times U(1{)}_F$, incorporating the local $SU(3)$ flavor symmetry with PM appearing as a vectorlike “fourth generation” to supplement the three generations of the SM. To ensure finite contributions to KM, the SM gauge group is arranged into Pati-Salam multiplets. The new extended dark gauge group presents a variety of interesting experimental signatures, including nontrivial consequences of the flavor symmetry being unified with the dark sector.

Nuclear transitions are one possible source of axions but past searches were restricted to specific transitions. In this manuscript, we propose to extend the search for axions and axionlike particles to a more complex environment that would result in a number of correlated observables. By including creation mechanisms that have their origin in the Carbon-Nitrogen-Oxygen (CNO) cycle, we show that the search for solar axions should not only be restricted to the keV-mass region. We discuss limitations, such as the lifetime and the mass, that create a challenge for an Earth-bound experiments. We show that it is possible to use the same creation mechanisms as used in solar axions to search with a comparable rate at nuclear power reactors.

We discuss the amplitude of the $B\to l^{+}{l}^{-}{l}^{\prime }{\nu }^{\prime }$ decays and the differential decay rate $d^2\mathrm{\Gamma }/d{q}^{2}d{q}^{\prime 2}$, $q$ the momentum of the $l^{+}{l}^{-}$ pair emitted from the electromagnetic vertex and $q^{\prime }$ the momentum of the $l^{\prime }{\nu }^{\prime }$ pair emitted from the weak vertex. For the relevant form factors, we construct dispersion representations in $q^2$, which consistently take into account the Ward identity constraints at $q^2=0$ and the contributions of light vector resonances. This allows a consistent description of the form factors in the range $0<q^2\le 1{\mathrm{GeV}}^2$ that saturates around 99% of the decay rate. The differential decay rate behaves at small $q^2$ as $d\mathrm{\Gamma }(B\to l^{+}{l}^{-}{l}^{\prime }{\nu }^{\prime })/d{q}^2\propto 1/q^2$ in the limit $m_l^{\prime }=0$ but contains also more singular contribution of order $m_l^{\prime 2}/q^4$, which we take into account. For the case $m_l^{\prime }\le m_l$, the latter may be neglected, and one obtains a mild logarithmic dependence of $\mathrm{\Gamma }(B\to l^{+}{l}^{-}{l}^{\prime }{\nu }^{\prime })$ on $m_l$. For the case $m_l\ll m_l^{\prime }$, however, the $m_l^{\prime 2}/q^4$ terms dominate the decay rate, leading to $\mathrm{\Gamma }(B\to l^{+}{l}^{-}{l}^{\prime }{\nu }^{\prime })\sim m_l^{\prime 2}/m_l^2$. We find the following features of the four-lepton $B$ decays: i) The decay rates $\mathrm{\Gamma }(B\to {\mu }^{+}{\mu }^{-}(\mu {\nu }_{\mu },e{\nu }_e))$ are fully dominated by the region of light vector resonances $q^2\simeq M_{\rho }^2,M_{\omega }^2$. ii) The decay rate $\mathrm{\Gamma }(B\to e^{+}{e}^{-}e{\nu }_e)$ receives comparable contributions from the region near $q^2\sim 4m_e^2$ and from the resonance region. iii) One finds a strong enhancement of the decay rate $\mathrm{\Gamma }(B\to e^{+}{e}^{-}\mu {\nu }_{\mu })\sim m_{\mu }^2/m_e^2$, which is dominated by the region $q^2\sim 4m_e^2$ due to the terms $O(m_{\mu }^2/q^4)$ in the differential distribution.

The fully heavy pentaquarks $cccc\overline{c}$ and $bbbb\overline{b}$ are systematically investigated within the chiral quark model and quark delocalization color screening model. The results are consistent in both of the models, and the effect of the channel coupling is crucial for forming a bound state of the fully heavy pentaquark system. Three possible fully heavy pentaquarks are obtained and are the $cccc\overline{c}$ state with $J^P=1/2^{-}$ and the mass of 7891.9–7892.7 MeV, the $bbbb\overline{b}$ state with $J^P=1/2^{-}$ and the mass of 23810.1–23813.8 MeV, and the $bbbb\overline{b}$ state with $J^P=3/2^{-}$ and the mass of 23748.2–23752.3 MeV. All these fully heavy pentaquark states are worth searching in future experiments.

For theories plagued with a sign problem at finite density, a Taylor expansion in the chemical potential is frequently used for lattice gauge theory-based computations of the equation of state. Recently, a new resummation scheme was proposed [S. Mondal, S. Mukherjee, and P. Hegde, Lattice QCD Equation of State for Nonvanishing Chemical Potential by Resumming Taylor Expansions, Phys. Rev. Lett. 128, 022001 (2022).] for such an expansion that resums contributions of correlation functions of conserved currents to all orders in the chemical potential. Here, we study the efficacy of this resummation scheme using a low energy model, namely the mean-field quark-meson model. After adapting the scheme for a mean-field analysis, we confront the results of this scheme with the direct solution of the model at finite density as well as compare with results from Taylor expansions. We study to what extent the two methods capture the analytical properties of the equation of state in the complex chemical potential plane. As expected, the Taylor expansion breaks down as soon as the baryon chemical potential reaches the radius of convergence defined by the Yang-Lee edge singularity. Encouragingly, the resummation not only captures the location of the Yang-Lee edge singularity accurately, but is also able to describe the equation of state for larger chemical potentials beyond the location of the edge singularity for a wide range of temperatures.