We propose a new inverse seesaw model based on hidden local $U(1)$ symmetry framework where the inverse seesaw mechanism is induced at one loop level. A Majorana mass term of singlet fermion is forbidden by the $U(1)$ symmetry and it is generated at one-loop level by introducing relevant particle contents to get loop diagram, inducing inverse seesaw mechanism. The same particle contents also contribute to lepton magnetic(electric) dipole moment and lepton flavor violating decays without chiral suppression. We can then obtain sizable muon anomalous magnetic dipole moment that accommodate with deviation from the standard model prediction. The constraints from lepton flavor violating decays and electron magnetic(electric) dipole moment are also discussed to explore testability of the model.

We investigate photon-hadron transverse energy-energy correlation (TEEC) and azimuthal correlations in the forward rapidity region for proton-proton and proton-lead collisions within the small $x$ saturation formalism based on the color glass condensate (CGC), supplemented by the initial-state and final-state parton shower simulation and hadronization using CASCADE. The study was performed in light of the upcoming FoCal detector of ALICE and the ATLAS detector upgrades with the extended pseudorapidity coverage. We predict a significant difference, at hadron-level, between the normalized TEECs in proton-proton and proton-lead collisions. Having a direct access to partonic subprocesses we also directly investigate the impact of the parton shower and hadronization on the TEEC. The ordinary azimuthal $\gamma$-hadron correlations show substantial suppression for proton-lead collision, as predicted earlier at parton level.

We present a detailed numerical and analytical study of the out-of-equilibrium dynamics of Model G, the dynamical universality class relevant to the chiral phase transition. We perform numerical 3D stochastic (Langevin) simulations of the $O(4)$ critical point for large lattices in the chiral limit. We quench the system from the high-temperature unbroken phase to the broken phase and study the nonequilibrium dynamics of pion fields. Strikingly, the nonequilibrium evolution of the two-point functions exhibits a regime of growth, a parametrically large enhancement, and a subsequent slow relaxation to equilibrium. We analyze our numerical results using dynamic critical scaling and mean-field theory. The growth of the two-point functions is determined by the nonlinear dynamics of an ideal non-Abelian superfluid, which is a limit of Model G that reflects the broken chiral symmetry. We also relate the nonequilibrium two-point functions to a long-lived parametric enhancement of soft pion yields relative to thermal equilibrium following a quench.

The deuteron “D” is the simplest nucleus with the spin $S=1$, therefore its electromagnetic structure is completely described by three different form factors: the charge $G_C(t)$, magnetic $G_M(t)$, and quadrupole $G_Q(t)$, where $t=-q^2$ is the momentum transfer squared of the electrons or the deuterons in the elastic scattering of electrons on deuterons. All three deuteron form factors are theoretically related to the functions $A(t)$, $B(t)$, and $T_{20}(t)$ to be numerically evaluated with errors, whereby $A(t)$ and $B(t)$ in a measurement of the differential cross section of elastic scattering of unpolarized electrons on unpolarized deuterons, and $T_{20}(t)$ in measurements of the elastic scattering of the longitudinally polarized electrons, respectively also on the polarized deuteron target. The obtained data are utilized to fix parameters of the deuteron electromagnetic form factors to be constructed in the form of the unitary and analytic model. Afterwards these form factors are analytically continued into the timelike region, with the aim to predict artificial behavior of the total cross section ${\sigma }_{\mathrm{tot}}(e^{+}{e}^{-}\to D\overline{D})(s)$. By means of the latter, artificial data with errors on the deuteron “effective” electromagnetic form factor are produced theoretically. Finally, such data render a possibility to investigate the deuteron damped oscillation regular structures.

We present a determination of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ from the decay $B\to D\ell {\nu }_{\ell }$ using a $365{\mathrm{fb}}^{-1}$ $e^{+}{e}^{-}\to \mathrm{\Upsilon }(4S)\to B\overline{B}$ data sample recorded by the Belle II experiment at the SuperKEKB collider. The semileptonic decay of one $B$ meson is reconstructed in the modes $B^0\to D^{-}(\to K^{+}{\pi }^{-}{\pi }^{-}){\ell }^{+}{\nu }_{\ell }$ and $B^{+}\to {\overline{D}}^0(\to K^{+}{\pi }^{-}){\ell }^{+}{\nu }_{\ell }$, where $\ell$ denotes either an electron or a muon. Charge conjugation is implied. The second $B$ meson in the $\mathrm{\Upsilon }(4S)$ event is not reconstructed explicitly. Using an inclusive reconstruction of the unobserved neutrino momentum, we determine the recoil variable $w=v_B·v_D$, where $v_B$ and $v_D$ are the four-velocities of the $B$ and $D$ mesons. We measure the total decay branching fractions to be $\mathcal{B}(B^0\to D^{-}{\ell }^{+}{\nu }_{\ell })=(2.06\pm 0.05(\mathrm{stat})\pm 0.10(\mathrm{sys}))\%$ and $\mathcal{B}(B^{+}\to {\overline{D}}^0{\ell }^{+}{\nu }_{\ell })=(2.31\pm 0.04(\mathrm{stat})\pm 0.09(\mathrm{sys}))\%$. We probe lepton flavor universality by measuring $\mathcal{B}(B\to De{\nu }_e)/\mathcal{B}(B\to D\mu {\nu }_{\mu })=1.020\pm 0.020(\mathrm{stat})\pm 0.022(\mathrm{sys})$. Fitting the partial decay branching fraction as a function of $w$ and using the average of lattice QCD calculations of the $B\to D$ form factor, we obtain $|V_{cb}|=(39.2\pm 0.4(\mathrm{stat})\pm 0.6(\mathrm{sys})\pm 0.5(\mathrm{th}))\times {10}^{-3}$.

The ${}^{144}\mathrm{Ce}–{}^{144}\mathrm{Pr}$ electron antineutrino source is one of the most suitable radiochemical sources for experiments searching for the oscillations of active neutrinos to the light sterile state. In the current work the $\beta$ spectra of the ${}^{144}\mathrm{Ce}–{}^{144}\mathrm{Pr}$ source have been measured by two types of $\beta$ spectrometers based on silicon Si(Li) detectors in order to determine the energy spectrum of electron antineutrinos emitted in the $\beta$ decay of ${}^{144}\mathrm{Pr}$ nuclei. The nuclear shape factor of the ground state beta transition in ${}^{144}\mathrm{Pr}-{}^{144}\mathrm{Nd}$ has been obtained with high precision: $C(W)=1+(-0.0301\pm 0.0007)W+(-0.101\pm 0.006)W^{-1}$. The reduced cross section for the inverse beta decay reaction on hydrogen for the ${}^{144}\mathrm{Pr}$ electron antineutrino source has been defined as $(4.7344\pm {0.0006}_{\mathrm{stat}}\pm {0.013}_{\mathrm{syst}})\times {10}^{-44}{\mathrm{cm}}^2{\text{decay}}^{-1}$ that provides sufficient sensitivity to search for a sterile neutrino with a mass of $m_4\sim 1\mathrm{eV}$ and a mixing angle $Si{n}^2(2{\theta }_{14})\sim 0.005$ using the standard disappearance method.

Calculations truncated at a fixed order in perturbation theory are accompanied by an associated theoretical uncertainty, which encodes the missing higher orders (MHOU). This is typically estimated by a scale variation procedure, which has well-known shortcomings. In this work, we propose a simple prescription to directly encode the missing higher order terms using theory nuisance parameters (TNPs) and estimate the uncertainty by their variation. We study multiple processes relevant for Large Hadron Collider physics at next-to-leading and next-to-next-to-leading order in perturbation theory, obtaining MHOU estimates for differential observables in each case. In cases where scale variations are well-behaved we are able to replicate their effects using TNPs, while we find significant improvement in cases where scale variation typically underestimates the uncertainty.

A systematic Hamiltonian formulation of the Einstein-Cartan system, based on the Hilbert-Palatini action with the Barbero-Immirzi and cosmological constants, is performed using the traditional Arnowitt-Deser-Misner decomposition and without fixing the time gauge. This procedure results in a larger phase space compared to that of the Ashtekar-Barbero approach as well as a larger set of first-class constraints generating gauge transformations that are on shell equivalent to spacetime diffeomorphisms and SO(1, 3) transformations. The imbalance in the number of components between the tetrad and the connection is resolved by the identification of second-class constraints implied by the action, which can be implemented by use of Dirac brackets or by solving them directly. The Hamiltonian system remains well-defined off the second-class constraint surface in an extended phase space with additional degrees of freedom, implying a more general geometric theory. Implications for canonical quantum gravity are discussed.

We investigate the use of the Gegenbauer procedure for time-domain reconstruction in frequency-domain calculations of the self-force on a particle orbiting a black hole. The conventional technique relies on the so-called method of extended homogeneous solutions (EHSs), which circumvents the Gibbs phenomenon that would otherwise hamper the reconstruction of the particle’s field from frequency modes. Unfortunately, the effectiveness of EHS reconstruction deteriorates rapidly with increasing orbital eccentricity, due to large numerical cancellations between frequency-mode contributions. Furthermore, the method is only suitable for bound orbits and cannot be fully applied in scattering scenarios. The Gegenbauer reconstruction procedure involves a reprojection of the partial Fourier representation onto a complementary basis of polynomials. The resulting series converges exponentially while averting the cancellation problem. We demonstrate the procedure with numerical results for the spherical harmonic modes of the scalar field sourced by a scalar charge in orbit around a Schwarzschild black hole. We illustrate the merits of this approach and discuss the challenges that remain for a full Gegenbauer-based self-force calculation.

Laser Interferometer Space Antenna (LISA) observations of massive black hole binaries (MBHBs) will provide long duration inspiral signals with high signal-to-noise ratio (SNR) data, ideal for testing general relativity (GR) in the strong-field and relativistic regime regime. We present an extension of the flexible theory-independent (FTI) framework, adapted to gravitational waves (GWs) from MBHBs observed with LISA, to perform parametrized inspiral tests of GR. This approach introduces generic deviations to the post-Newtonian (PN) coefficients of the frequency-domain GW phase while accounting for the time- and frequency-dependent instrument response, thus effectively identifying potential deviations from GR by constraining modifications to the PN phasing formula. Complementary analyses using Fisher matrix and full Bayesian approaches confirm that LISA observations could improve constraints on agnostic, scale-independent deviations from GR by at least two orders of magnitude compared to the most recent LIGO-Virgo-KAGRA measurements. Since LISA’s sensitivity to different GW phases—inspiral, merger, and ringdown—varies across the MBHB parameter space with masses between ${10}^4$ and ${10}^7{M}_{\odot }$, the optimal regime for testing agnostic deviations is not known a priori. Our results illustrate how the strength of these constraints depends significantly on both the total mass and the SNR, reflecting the trade-off between inspiral and merger-ringdown contributions to the observed signal. We also investigate the interplay between inspiral-only versus inspiral-merger-ringdown analyses in constraining these inspiral deviation parameters. This work contributes to the development of robust tests of GR with LISA, enhancing our ability to probe the nature of gravity and BHs with GW observations.

We study linear perturbations on top of the static and spherically symmetric background of dyonic black hole solutions endowed with electric and magnetic charges, as well as a scalar hair, in the lowest-order $U(1)$ gauge-invariant scalar-vector-tensor theories. The presence of magnetic charges in the background solutions gives rise to a mixing between the odd-parity and even-parity sectors of perturbations, which makes it impossible to analyze each sector separately. Thus, we expand the action up to second order in both odd-parity and even-parity perturbations and derive the general conditions for the absence of ghosts and Laplacian instabilities. We apply these general conditions to extended Einstein-Maxwell-scalar theories, which encompass numerous types of concrete models from the literature known to have dyonic black hole solutions with the scalar hair, and examine their stabilities. Our general framework for studying stability conditions and dynamics of perturbations can be applied to a wide variety of theories, including nonlinear electrodynamics coupled to a scalar field, as well as to calculations of black hole quasinormal modes.

In general relativity, gravity around a black hole is universally regarded as an attractive force. However, quantum effects may significantly alter this classical picture and thus affect the dynamics of test particles. In this work, we investigate geodesic motion in a recently proposed covariant effective quantum black hole model, the ZLMY type I model in [Black holes and covariance in effective quantum gravity, Phys. Rev. D 111, L081504 (2025).]. Our analytical study reveals that, at the Planck scale, gravity can exhibit a repulsive character, most notably in trajectories involving turning points. These findings suggest that quantum corrections could fundamentally modify our conventional understanding of gravitational interactions in certain regimes.

According to the no-hair theorem, stationary black holes are uniquely characterized by their mass, charge, and angular momentum. In this paper, we explore quantum hair by deriving the quantum-corrected black hole metric within the Barvinsky-Vilkovisky formalism. The quantum-corrected metric is obtained perturbatively around flat spacetime without assuming either the commutativity between the nonlocal operator and covariant derivatives or the nonlocal Gauss-Bonnet theorem, both of which are adopted in previous studies. Using this metric, we evaluate the deflection angle in the strong-field limit and compute the associated strong gravitational lensing observables, such as the angular separation and the relative magnification. Our results show that as the quantum hair, determined by the number of virtual massless quantum fields in the nonlocal effective action, increases, the photon sphere radius, the strong deflection angle, and the relative magnification all increase, whereas the angular separation decreases. As a result, we demonstrate that the quantum hair affects not only the black hole geometry but also its strong gravitational lensing effects.

We explicitly show that certain four-dimensional infinitesimal group actions with three-dimensional orbits are related by double Wick rotations. In particular, starting with the symmetries of the spherical/hyperbolic/planar Taub-NUT spacetimes, one can obtain symmetries of the near-horizon extreme Kerr (NHEK) geometry or swirling universe by complex analytic continuations of coordinates. Similarly, the static spherical/hyperbolic/planar symmetries (i.e., symmetries of the Schwarzschild spacetime and other A-metrics) are mapped to symmetries of the B-metrics (or Melvin spacetime). All these mappings are theory independent—they constitute relations among symmetries themselves, and, hence among the classes of symmetry-invariant metrics and electromagnetic field strengths, rather than among specific solutions. Consequently, finding, e.g., vacuum Taub-NUT–type solutions in a given gravitational theory automatically yields vacuum NHEK- or swirling-type solutions of that theory, with a possible extension to the electromagnetic case.

Relativistic collimated outflows, or jets, provide a crucial mode of active galactic nucleus feedback. Although the jets extract their energy from the black hole (BH) rotation, their effect on the BH spin is poorly understood. Because the spin controls radiative and mechanical BH feedback, lack of first-principles models for BH spin evolution limits our ability to interpret observations, including the recent LIGO-Virgo-KAGRA spin constraints. Particularly important are luminous disks, which rapidly grow and strongly torque their BHs. Jetless and weakly magnetized “standard” luminous disks spin up their BHs to near-maximum dimensionless spin, $a_{\mathrm{eq},\mathrm{NT}}=0.998$. However, sufficient large-scale vertical magnetic flux can cause the inner disk to enter a magnetically arrested disk (MAD) state, whose jets can efficiently extract BH rotational energy and significantly spin down the BH. Indeed, Lowell et al. [Rapid black hole spin-down by thick magnetically arrested disks, Astrophys. J. 960, 82 (2024)] found that nonradiative, thick MADs spin down their BHs to very low $a_{\mathrm{eq},\mathrm{MAD}}^{\text{thick}}=0.07$. Moreover, their analytic model predicted that luminous, thin MADs also spin down their BHs to low $a_{\mathrm{eq},\mathrm{MAD}}^{\mathrm{thin}}\sim 0.3–0.5$. To test this prediction, we perform 3D general relativistic (radiation) magnetohydrodynamic simulations of MADs across a wide range of BH spin ($-0.9\le a\le 0.99$) and disk dimensionless thickness ($0.03\le h/r\le 0.3$, which corresponds to Eddington ratio, $0.35\le \dot{m}/{\dot{m}}_{\mathrm{Edd}}\le \infty$). We find that luminous, thin MADs ($0.03\le h/r\le 0.1$) efficiently spin down their BHs to a low universal equilibrium spin value, $a_{\mathrm{eq},\mathrm{MAD}}^{\mathrm{thin}}\approx 0.3$: a maximally spinning BH ($a=1$) spins down to $a=0.5$ after accreting just 25% of its initial mass. Our results are consistent with quadratic convergence, $a_{\mathrm{eq},\mathrm{MAD}}^{\mathrm{fit}}\simeq 0.3–2.7(h/r{)}^2\to 0.3$ as $h/r\to 0$, which we attribute to the aggressive cooling that renders disk thermodynamics irrelevant and magnetic forces insensitive to thermal $h/r$. We finish by discussing the astrophysical implications.

We revisit sterile neutrino production enabled by nonstandard interactions (NSIs) among active neutrinos mediated by new bosons. We focus on vector mediators, including neutrinophilic, gauged $L_{\mu }-L_{\tau }$, and $B-L$ realizations, that modify in-medium dispersion and scattering, thereby altering the active-sterile conversion history. Building on a novel production framework with NSI thermal potentials and collision integrals, we compute nonthermal phase-space distributions across sterile neutrino mixing and NSI parameters and map each point to an equivalent thermal warm dark matter particle mass $m_{\mathrm{th}}$ via linear theory transfer function fitting with the cosmological structure formation Boltzmann solver. This enables a direct reinterpretation of state-of-the-art structure formation limits from Milky Way satellites, strong lensing, and the Lyman-$\alpha$ forest. These limits, in conjunction with x-ray decay searches, as well as results from a wide variety of particle physics experiments allow for a more complete examination of these models. We find that these vector-mediated models are ruled out when the full combination of current constraints, listed above, are taken into account. NSI scalar-mediated models and models with low reheating temperatures remain viable.

In the context of gauge-Yukawa theories with trans-Planckian asymptotic safety, quantum scale symmetry can prevent the appearance in the Lagrangian of couplings that would otherwise be allowed by the gauge symmetry. Such couplings correspond to irrelevant Gaussian fixed points of the renormalization group flow. Their absence in the theory implies that different sectors of the gauge-Yukawa theory are secluded from one another, in similar fashion to the effects of a global or a discrete symmetry. As an example, we impose the trans-Planckian scale symmetry on a model of grand unification based on the gauge group SU(6), showing that it leads to the emergence of several fermionic weakly interacting massive particles dark matter candidates whose coupling strengths are entirely predicted by the UV completion.

A low-mass right-handed neutrino could interact with electroweak bosons via mixing, a mediator particle, or loop corrections. Using an effective field theory, we determine constraints on these interactions from $W$-boson measurements at hadron colliders. Due to the difference in the initial states at the Tevatron and the LHC, $W$-boson decays to a right-handed neutrino would artificially increase the mass measured at the Tevatron while only affecting the difference between $W^{+}$ and $W^{-}$ mass measurements at the LHC. Measurements from CDF and the LHC are used to infer the corresponding parameter values, which are found to be inconsistent between the two. The LHC experiments can improve sensitivity to these interactions by measuring the cosine of the helicity angle using $W$ bosons produced with transverse momentum above $\approx 50\mathrm{GeV}$.

In this Letter, we propose that a proper constituent gluon mass $m_g=450\mathrm{MeV}$ can be applied to identify the hybrids composed of quarks and gluons. By investigating the spectra and decay widths of the light hybrids $(q\overline{q}g)$ with $J^P=1^{-+}$, we find the ${\pi }_1(1600)$ and ${\eta }_1(1855)$ may not be explained as $1^{-+}$ hybrids, simultaneously, and the ${\eta }_1(1855)$ observed by BESIII may not be a hybrid. In addition, we predict an existence of a hybrid ${\eta }_1(1640)$, which can be verified by searching the $a_1(1260)\pi$ channel. Moreover, we suggest the $K_1(1270)\overline{K}$ and $K_1(1270)\pi$ as the golden channels to search for isospin-0 and isospin-$\frac{1}{2}$ hybrids, respectively.

In this paper, we employ the gauge-gravity duality to study jet quenching (JQ) phenomena in the quark-gluon plasma. For this purpose, we implement holographic quantum chromodynamics (QCD) models constructed from an Einstein-Maxwell-dilaton gravity at finite temperature and finite chemical potential for light and heavy quarks. The models capture both the confinement and deconfinement phases of QCD and the first-order phase transitions. We calculate the JQ parameter in different models and compare them with the experimental data obtained in heavy-ions studies. In particular, we investigate how JQ, as a function of temperature $T$, chemical potential $\mu$, and magnetic field $c_B$, serves as a probe for identifying first-order phase transitions within the $(T,\mu ,c_B)$ parameter space of holographic QCD. Particular attention is paid to the dependence of JQ on the parameter $\nu$, which characterizes longitudinal versus transverse anisotropy relative to the heavy-ion collision axis. By analyzing the dependence of the JQ parameters on these thermodynamic variables, we map critical regions associated with phase boundaries. We compare our findings to earlier studies of the running coupling constant’s behavior within the gauge-gravity duality framework. This approach provides new insights into the interplay between nonperturbative dynamics and phase structure in strongly coupled systems.