We present a systematic analysis of Coulomb corrections for leptonic ($B_{d,s}^0\to {\ell }^{+}{\ell }^{-}$), semileptonic ($B_{d,s}^0\to h^0{\ell }^{+}{\ell }^{-}$, $B_{d,s}^0\to V^0{\ell }^{+}{\ell }^{-}$) and radiative leptonic ($B_{d,s}^0\to \gamma {\ell }^{+}{\ell }^{-}$) decays of neutral $B$-mesons. The relativization of the Coulomb factor was performed by comparing the Gamow-Sommerfeld-Sakharov factor, the exact relativistic approach of Crater-Alstine-Sazdjian applied by us to scalar systems, and well-known one-loop QED calculations. Coulomb corrections are calculated for differential, angular, and double-differential distributions, as well as for partial decay widths. We also discuss the role of the Coulomb factor among other QED corrections, in particular, the contribution of soft-photon radiation, which is effectively simulated in experiments by tools such as photos. For the $B_s^0\to {\mu }^{+}{\mu }^{-}$ channel, Coulomb corrections improve the prediction of the partial width to $\delta =|{\mathcal{B}}^{(\exp )}-{\mathcal{B}}^{(\mathrm{theory})}|/{\mathcal{B}}^{(\exp )}=2\%$. This improvement brings the prediction closer to the LHCb/CMS experimental results within the current experimental (11%) and theoretical (5% lattice QCD) errors. In the decays $B^0\to K^0{\mu }^{+}{\mu }^{-}$ and $B^0\to K^{0*}{\mu }^{+}{\mu }^{-}$, Coulomb effects also reduce the discrepancies between theoretical predictions and experimental data (from $\delta =2\%$ to less than $\delta =1\%$ and from $\delta =11\%$ to $\delta =4\%$ respectively). Finally, for the decays involving $\tau$-leptons, the Coulomb correction reaches 4%. While currently smaller than the dominant form-factor uncertainties and experimental errors, the Coulomb correction represents a non-negligible systematic effect. It should be accounted for in the high-precision era of $B$-physics, where such effects may become significant for the interpretation of potential new physics signals.

$D$ meson decays into neutral kaons involve both Cabibbo-favored and doubly Cabibbo-suppressed amplitudes as well as final-state kaon mixing, providing abundant sources of $CP$ violation. In this work, we analyze $CP$ asymmetries in the $D\to K_{S,L}^{0}P$ and $D\to K_{S,L}^{0}V$ decays, where $P$ and $V$ denote pseudoscalar and vector mesons, respectively. The formulas of the time-dependent and time-integrated $CP$ asymmetries in these modes are derived, in which the $D^0-{\overline{D}}^0$ mixing effects and the $K_L^0$ modes are considered for the first time. The hadronic parameters that determine $CP$ asymmetries are extracted by the global fit of branching fractions within the topological diagram approach. A significant result is that the tension between theoretical predictions and experimental data for the $K_S^0-K_L^0$ asymmetries in $D^0\to K_{S,L}^0\omega$ and $D^0\to K_{S,L}^0\varphi$ modes is mitigated. The $CP$-violating effects arising from the interference between Cabibbo-favored and doubly Cabibbo-suppressed amplitudes with neutral kaon mixing could reach to $\mathcal{O}({10}^{-3})$ order in the $D^{+}\to K_S^0{\pi }^{+}$, $D_s^{+}\to K_S^0{K}^{+}$, $D^0\to K_S^0{\rho }^0$, and $D^0\to K_S^0\varphi$ modes. The difference between the $CP$ asymmetries in the $D^{+}\to K_S^0{\pi }^{+}$ and $D_s^{+}\to K_S^0{K}^{+}$ modes will be available on LHCb and Belle II in the near future.

We present a systematic analysis of the semileptonic decays $B_{(s)}\to D_{(s)}(1S,2S)\ell {\nu }_{\ell }$ and $B_{(s)}\to D_{(s)}^{*}(1S,2S)\ell {\nu }_{\ell }$ with $\ell =e$, $\mu$, $\tau$ within the covariant light-front quark model. Using the form factors of the transitions $B_{(s)}\to D_{(s)}(1S,2S)$ and $B_{(s)}\to D_{(s)}^{*}(1S,2S)$, we calculate the branching ratios of the relevant semileptonic decays and find that $\mathrm{Br}(B_{(s)}\to D_{(s)}{\ell }^{\prime }{\nu }_{{\ell }^{\prime }})$ and $\mathrm{Br}(B_{(s)}\to D_{(s)}^{*}{\ell }^{\prime }{\nu }_{{\ell }^{\prime }})$ with ${\ell }^{\prime }=e$, $\mu$ agree well with the data, while $\mathrm{Br}(B_{(s)}\to D_{(s)}\tau {\nu }_{\tau })$ and $\mathrm{Br}(B_{(s)}\to D_{(s)}^{*}\tau {\nu }_{\tau })$ are systematically smaller than the experimental measurements. This naturally gives rise to the so-called $\mathcal{R}(D)$ and $\mathcal{R}(D^{*})$ anomalies. Our predictions $\mathcal{R}(D)=0.261\pm 0.013$ and $\mathcal{R}(D^{*})=0.228\pm 0.026$ show $3.1\sigma$ and $2.1\sigma$ deviations from the current experimental world averages compiled by the Heavy Flavor Averaging Group, respectively, yet deviate only by $0.16\sigma$ and $1.5\sigma$ from the latest LHCb measurements. For the decays $B_{(s)}\to D_{(s)}(2S)\ell {\nu }_{\ell }$ and $B_{(s)}\to D_{(s)}^{*}(2S)\ell {\nu }_{\ell }$, their branching ratios lie in the range ${10}^{-4}-{10}^{-3}$, which are much larger than the results from the Bethe Salpeter equation but agree with the relativistic quark model calculations. Furthermore, we also calculate the forward-backward asymmetries ${\mathcal{A}}_{\mathrm{FB}}$ and longitudinal polarization fractions $f_L$ for the corresponding decays. Our predictions are consistent with most other theoretical results and experimental data.

Precise neutrino-nucleon amplitudes are essential ingredients for predicting neutrino event rates in current and upcoming long-baseline neutrino oscillation experiments. A common neutrino interaction with a low reaction threshold and with most of the energy carried by two final state particles is quasielastic scattering, for which the nucleon axial form factor, $F_A(Q^2)$, is a dominant source of uncertainty. Improvements to the nucleon axial form factor rely on neutrino scattering data with elementary targets to reduce or eliminate the need for nuclear modeling systematics. This work examines constraints on the nucleon axial form factor that can be achieved from datasets of neutrino scattering on deuterium targets, Lattice QCD predictions, and from the recent hydrogen target data from the MINERvA Collaboration. Significant tension is found between hydrogen and deuterium target data, suggesting that extractions from deuterium underestimate both the central value and uncertainty of the form factor. Parametrizations for and uncertainties of the nucleon axial form factor using the $z$ expansion are provided.

A search is performed for the electroweak pair production of charginos and associated production of a chargino and neutralino, each of which decays through an $R$-parity-violating coupling into a lepton and a $W$, $Z$, or Higgs boson. This search targets the Higgs boson decay channel of the charginos and neutralinos, using events with three or more $b$-tagged jets and one or two electrons or muons. The analyzed data corresponds to an integrated luminosity of $140{\mathrm{fb}}^{-1}$ and $56{\mathrm{fb}}^{-1}$ of proton-proton collision data produced by the Large Hadron Collider at center-of-mass energies of $\sqrt{s}=13\mathrm{TeV}$ and $\sqrt{s}=13.6\mathrm{TeV}$, respectively, collected by the ATLAS experiment between 2015 and 2023. The data are found to be consistent with predictions from the Standard Model. The results are interpreted as limits at 95% confidence level on model-independent cross sections for processes beyond the Standard Model. Limits are also set on the production of charginos and neutralinos for a minimal supersymmetric Standard Model with an additional $B-L$ gauge symmetry that is spontaneously broken. Charginos and neutralinos with masses between 150 GeV and 1100 GeV are excluded at 95% confidence level for a scenario in which they decay via Higgs bosons, assuming equal decay branching fractions to each lepton flavor. Additional limits on chargino and neutralino production are derived for flavor-specific decay scenarios where the charginos decay into a single lepton flavor.

This paper presents the first neutrino cross-section measurement from the ICARUS detector at Fermilab, using Neutrinos at the Main Injector (NuMI) beam data collected from two beam operation periods corresponding to $2.5\times {10}^{20}$ protons-on-target in neutrino beam mode. The signal is defined by events with no pions produced in the final state, a topology dominated by charged-current quasielasticlike signatures. The measurement is reported as flux-averaged differential cross sections as functions of kinematic variables that provide sensitivity to the complex nuclear effects that often dominate the systematic uncertainty budgets of neutrino oscillation measurements. Specifically, this work reports cross sections in two angular variables—the angle of the outgoing lepton and the opening angle between the lepton and leading proton—and two variables characterizing the kinematic imbalance between the muon and proton in the plane transverse to the incoming neutrino. These results are compared against predictions from a variety of neutrino event generators, with $p$ values calculated between the extracted cross sections and each prediction. Overall, the predictions agree with the data; however, the current budget of uncertainties does not yet provide sufficient discriminating power to favor a specific model.

We study quantum chaos in $\mathrm{T}\overline{\mathrm{T}}$ deformed two-dimensional conformal field theories with gravitational anomalies and their holographic dual descriptions in topologically massive gravity. Using pole-skipping and shock-wave analysis, we extract the Lyapunov exponent and butterfly velocity and analyze the interplay between irrelevant deformations and parity-violating dynamics. We find that the chaos bound remains saturated, while the butterfly velocity exhibits nontrivial dependence on the deformation parameter and anomaly. We also identify a Hagedorn regime in which the chaotic response becomes complex valued, signaling a breakdown of the physical branch of the deformed theory.

We introduce the celestial energy-energy correlator (cEEC), an infrared and collinear safe observable that makes the celestial conformal symmetry of four-dimensional scattering manifest. The cEEC is defined as a correlation function of average null energy operators measured on boost eigenstates and takes the form of a four-point function in a fictitious two-dimensional conformal field theory on the celestial sphere. An important feature of the cEEC is that it smoothly interpolates between different key regimes of perturbative gauge theory and gravity, such as the collinear limit, the Sudakov limit, and the Regge limit. We compute the cEEC to the first nontrivial order in $\mathcal{N}=4$ super Yang-Mills theory, pure Yang-Mills theory, Einstein gravity, and $\mathcal{N}=8$ supergravity. In $\mathcal{N}=8$ supergravity, the cEEC is uniquely determined by celestial symmetries and boundary data, demonstrating that bootstrap methods can yield closed-form results for this class of observables.

The Laser Interferometer Space Antenna (LISA) will enable precision studies of extreme and intermediate mass ratio inspirals (EMRIs/IMRIs), providing unique probes of astrophysical environments of galactic nuclei and strong-field gravity. Using a fully relativistic pipeline across primary masses $m_1\in [5\times {10}^4,{10}^7]M_{\odot }$ and secondary masses $m_2\in [1,{10}^4]M_{\odot }$, we map instrumental performance directly to detection horizons and parameter measurement precision. EMRIs with $m_1={10}^7{M}_{\odot }$ and $m_2\sim 1M_{\odot }$ are the most sensitive to instrument degradation, with redshift horizons at $z\sim 0.01$, while IMRIs are the least sensitive to degradation and reach redshifts $z\sim 1–3$. All prograde systems considered achieve subpercent spin precision within 3 months of observation. The full 4.5-yr mission increases the horizon of systems with $m_1={10}^7{M}_{\odot }$ and $m_2\sim 1M_{\odot }$ by a factor of $\sim 4$ and improves sky localization by 1 to 2 orders of magnitude reaching $<10{\mathrm{deg}}^2$. IMRI detection is robust against degradation, but their parameter estimation is more vulnerable due to fewer cycles in band. With the full baseline, EMRI observations constrain scalar dipole emission and Kerr quadrupole deviations below ground-based bounds by 1 to 2 orders of magnitude. We release the accompanying software and an interactive website to enable the community to rapidly quantify the scientific potential of EMRIs and IMRIs.

The foundation for modeling the coupling of the internal structure of compact objects in binary systems to their dynamics and emitted gravitational waves is a systematic effective field theory (EFT) framework, where each compact object is replaced by a worldline endowed with a set of internal degrees of freedom. These degrees of freedom encode finite-size effects and thereby distinguish between different classes of compact objects. Among finite-size effects, tidal interactions play a central role, as they are associated to various kinds of deformations of a body under the influence of external tidal fields. In this work, we analyze the dynamical tidal response of Kerr black holes to generic-spin perturbations, focusing primarily on the scalar and gravitational cases, and working to linear order in frequency. We establish an EFT description of the perturbed black hole that accounts for the couplings between the spin, gravitoelectric and -magnetic tidal fields. We match this to wavelike solutions to the full black hole perturbation equations in order to determine the tidal response coefficients. In particular, we obtain the dynamical Love number, which appears at linear order in frequency for spinning black holes, and derive an approximate expression for the dynamical tidal response, including both dissipative and conservative pieces. We also examine several technical subtleties that arise in the matching procedure, with special emphasis on the mixing of multipolar modes induced by the spin of the compact object, which proves to be essential for a consistent treatment.

Extreme-mass-ratio inspirals (EMRIs) are one of the main sources of gravitational waves expected in the low-frequency band, where space-based detectors like Laser Interferometer Space Antenna (LISA) will operate. The large number of gravitational-wave cycles accumulated in the EMRI signal in the strong-field regime makes them very precise probes of the local spacetime geometry that are highly sensitive to deviations from the Kerr black hole paradigm. In this work, we investigate EMRIs around generic, non-Kerr compact objects characterized by an arbitrary and rich multipolar structure. At leading post-Newtonian and linear mass-ratio orders, we incorporate in the waveform model both the axisymmetric and nonaxisymmetric components of the mass quadrupole and octupole moments, parametrizing in this way the breaking of two fundamental symmetries of the Kerr metric. We study the impact of these modifications on the waveform following the philosophy of the EMRI analytic kludge models. In our case, the orbital evolution follows from Lagrangian that contains of the multipolar structure of the primary, including for the first time the nonaxisymmetric multipole moments that break axial symmetry. Then, using Fisher-matrix analysis, we assess the capability of LISA to constrain deviations of the multipole moments from their Kerr values and, in particular, the possibility of detecting symmetry-breaking effects. In this way, we analyze how effectively LISA will be able to probe models beyond General Relativity that predict horizon-scale modifications, such as the fuzzball model proposed in string theory. Our results demonstrate that future LISA observations of EMRIs will provide powerful and unprecedented tests of black hole structure and the underlying theory of gravity. In particular, with one year of LISA data from the inspiral of a $10M_{\odot }$ compact object into a rotating supermassive black hole of ${10}^6{M}_{\odot }$ and signal-to-noise ratio of 30, it will be possible to place tight bounds on deviations from the two fundamental symmetries of the Kerr metric, constraining equatorial symmetry breaking in the mass multipole sector to the ${10}^{-1}$ level and axial symmetry breaking to the ${10}^{-2}$ level.

We explore the properties of bilinear products for black hole quasinormal modes (QNMs) formulated on hyperboloidal foliations. We find that, although QNM solutions are smooth and finite on future-directed hyperboloids, the integrand of the bilinear form with respect to which the modes are orthogonal is still divergent. This is a result of the reflection (equivalently, $CPT$) transformation required in the definition of the products, which modifies the behavior of the integrand at the boundaries. We present several regularization procedures that yield a finite and well-defined bilinear form. In addition, we examine an alternative definition of the bilinear products that incorporates flux contributions, discussing its advantages and limitations. Finally, we define the QNM excitation factors and coefficients within the hyperboloidal framework in terms of the bilinear products and compute them explicitly for a choice of mode numbers and constant initial data. For concreteness, we work with the QNMs associated with scalar perturbations of the Schwarzschild family of spacetimes.

This paper examines interacting dark energy models within the Chevallier-Polarski-Linder (CPL) parametrization, emphasizing both theoretical structure and observational viability. Two commonly adopted interaction terms are considered: $Q=\beta H{\rho }_{\mathrm{de}}$ and $Q=\beta H{\rho }_{\mathrm{c}}$. We derive exact analytic solutions that describe how the dark sector evolves. These solutions involve incomplete gamma functions and reveal a nontrivial mathematical structure that is often missed in numerical analyses. We perform a Bayesian analysis using current cosmological observations, including the Hubble parameter, Type Ia supernovae, baryon acoustic oscillations, and CMB data. Relative to the non-interacting CPL scenario, the interacting model with $Q=\beta H{\rho }_{\mathrm{de}}$ yields a modestly improved fit, as indicated by the Akaike information criterion. However, the Bayesian information criterion penalizes increased model complexity, leading to a continued preference for $\mathrm{\Lambda }$ cold dark matter. In contrast, the interaction model that depends on dark matter density does not provide observational support. The preferred interacting scenario indicates that the dark energy equation of state evolves dynamically, transitioning from an effective phantom regime at high redshift to quintessencelike behavior at late times. Further analysis suggests the possibility of a future transition from accelerated to decelerated expansion, primarily associated with the reconstructed CPL dynamics, while the interaction alters the detailed evolution of the dark sector and the precise transition epoch. These findings suggest that interacting dark energy models within the CPL framework enrich the standard cosmological model by introducing more diverse phenomenology while maintaining consistency with current observations.

Resolving the impact of magnetic field instabilities in triggering small scale turbulent flow and the associated rearrangement of the field is of critical importance in understanding multimessenger observables in binary neutron star mergers and angular momentum transport in neutron stars and accretion disks. Direct simulation of these instabilities are unfeasible, however large-eddy simulations can incorporate the impact of this turbulence with a subgrid model. We present the first machine-learning-based subgrid model for special relativistic magnetohydrodynamics, trained using a neural network. We demonstrate its performance in online simulations of the 3D Kelvin-Helmholtz instability through both a priori and a posteriori tests. Evaluated in a low resolution simulation, our model captures magnetic field amplification of a simulation at 4 times the resolution with a speedup factor of 44. This demonstrates the applicability of such methods in general relativistic simulations of neutron star mergers and other scenarios.

In this work, we develop analytic asymptotic methods for computing the Fourier modes of gravitational waves from post-Newtonian binary systems in the quasi-Keplerian parametrization in the high eccentricity regime. We also derive the large-eccentricity asymptotic expansion of the eccentricity enhancement function appearing in the tail contributions to the radiation. Furthermore, based on these results, we construct an end point-constrained analytic approximation that significantly accelerates the computation of the Fourier modes at large eccentricity. The overall error of this analytic approximation is controlled within ${10}^{-3}$, and it remains valid for Fourier modes with $p\le 200$ and $e\le 0.9$. This approach provides analytic building blocks for modeling frequency-domain gravitational waves from highly eccentric binaries.

We determine the future sensitivity of the TRIDENT neutrino telescope to dark matter annihilation in the Galactic Center. By applying the full detector design and assuming an Navarro-Frenk-White (NFW) halo profile, we show that TRIDENT will probe annihilation cross section down to $⟨\sigma v⟩\approx 5\times {10}^{-27}{\mathrm{cm}}^3{\mathrm{s}}^{-1}$ for 10 TeV dark matter, falling below the thermal freeze-out benchmark. The analysis is carried out with all-flavor neutrino interactions, where we demonstrate that cascade events, primarily due to ${\nu }_{e,\tau }$, show greater sensitivity to a dark matter signal compared to the more commonly studied track events. Furthermore, we highlight the impact of a previously overlooked background, Galactic neutrinos produced from interactions between hadronic cosmic rays and interstellar gas. We find dark matter sensitivities are more strongly degraded in the high energy region above $\sim 10\mathrm{TeV}$, with a maximal weakening of approximately a factor of 2. This effect remains smaller than the uncertainty associated with the dark matter density profile but can nonetheless mimic a positive annihilation signal. We contextualize these results with a concrete particle model and show that TRIDENT will be able to probe the most interesting untested parts of parameter space.

Ultraheavy asymmetric dark matter (DM) particles captured by compact stars can thermalize, self-gravitate, and collapse to form an endoparasitic black hole (EBH), whose subsequent growth may transmute the host star into a black hole. The continued existence of old millisecond pulsars (MSPs) and white dwarfs (WDs) thus places powerful constraints on the DM particle mass $m_{\chi }$ and the DM-nucleon scattering cross section ${\sigma }_{\mathrm{n}\chi }$. In this work, we derive an analytical expression for the transmutation timescale by solving the EBH growth equation while consistently accounting for the Bondi accretion of stellar matter, Hawking evaporation, and allowing for the possibility of sustained DM feeding of the EBH in a steady-state capture regime. We also incorporate quantum mechanical effects in the baryonic accretion process by modeling particle absorption in regimes where the hydrodynamic description breaks down, thereby providing a unified treatment of EBH growth across both particle and fluid regimes. Adopting a physically transparent collapse criterion for both fermionic and bosonic asymmetric DM, we compute the EBH transmutation timescales for representative MSPs and WDs residing in environments with different DM densities. Although the underlying physical ingredients are broadly the same as those considered in previous studies, the present work derives updated constraints through a closed-form analytical treatment of EBH growth, together with the adopted prescription for the EBH formation timescale. Consequently, we obtain a lower critical EBH mass for sustained growth and revised transmutation timescales. Requiring the transmutation time to exceed $\sim 1\mathrm{Gyr}$ for MSPs and $\sim 10\mathrm{Gyr}$ for WDs, we derive revised constraints on ${\sigma }_{\mathrm{n}\chi }$ over the DM mass range ${10}^6–{10}^{14}\mathrm{GeV}$. Notably, we show that EBHs with initial masses as small as $\sim 4\times {10}^4\mathrm{kg}$ can undergo sustained growth, thereby extending the region of the DM parameter space that can be probed using compact stars.

Accurately modeling the inspiral-merger-ringdown (IMR) signal of coalescing compact objects is essential for the test of general relativity. However, it is known that astrophysical environments can distort gravitational-wave (GW) signal and, if ignored, may bias parameter estimation or even our understanding of gravity. Previous studies suggest that the leading-order effects of many astrophysical environments can be modeled in a unified way by introducing an effective acceleration. However, such models are based on stationary phase approximation (SPA) and post-Newtonian (PN) formalism, which are inconsistent with the fast orbital evolution and strong gravity in the final merger-ringdown phase. To overcome this limit, we introduce frequency-domain spectral differentiation (FSD), which maps the time shift of the signal caused by acceleration into a differentiation in the frequency domain. The mapping does not rely on SPA or PN formalism, therefore can be used to construct the accelerated waveform across the entire IMR phases. We compare the FSD waveforms with the conventional $\mathrm{SPA}+\mathrm{PN}$ ones, and find that the former more faithfully match the simulated signals of accelerating sources, especially in the merger-ringdown phase and when higher-order FSD corrections are included. A Fisher information matrix analysis suggests that FSD waveforms can achieve higher precision than $\mathrm{SPA}+\mathrm{PN}$ waveforms in measuring effective acceleration. Therefore, the FSD method offers a more self-consistent treatment of the accelerationlike class of astrophysical environmental effects in the final merger-ringdown phase of binary GW sources.

Future gravitational-wave detectors, such as the Einstein Telescope and Laser Interferometer Gravitational Wave Observatory (LIGO) Voyager, are planned to implement cryogenic technology. For the Kamioka gravitational wave detector, where cryogenics has already been adopted, issues related to the growth of an ice layer on mirror surfaces were reported. Further studies have confirmed the presence of nanometric layers in cryogenic experiments in which ice led to an increase in optical loss and to oscillations of the mirror reflectance. In this study, we investigate the mechanical loss of an ice layer grown on a silicon substrate. The results show that the total mechanical loss increases over time with the thickness of the ice layer, indicating that even a few nanometers of ice can impact the sensitivity of gravitational-wave detectors.

More than one dark sector particle transforming under the same symmetry provides one stable dark matter (DM) component, which undergoes coannihilation with the heavier particle(s) decaying to DM. Specific assumptions on the kinematics and on the coupling parameters may render the heavier component(s) stable and contribute as DM. The choices of the charges of the dark sector fields under transformation play a crucial role in the resultant phenomenology. In this paper, we systematically address the possibility of obtaining two scalar DM components under ${\mathcal{Z}}_N$ symmetry. We consider both the possibilities of DM being weakly interacting massive particles (WIMPs) or pseudofeebly interacting massive particles (pFIMPs). We elaborate upon the ${\mathcal{Z}}_3$ symmetric model, confronting the relic density-allowed parameter space with the recent most direct and indirect search bounds and prospects. We also highlight the possible distinction of the allowed parameter space in single component and two-component cases as well as between WIMP-WIMP and WIMP-pFIMP scenarios.