We analyze the sensitivity of nonradial fluid oscillation modes and tidal deformations in neutron stars to high-order nuclear empirical parameters (NEPs). In particular, we study the impact of the curvature and skewness of the symmetry energy $K_{\mathrm{sym}}$, $Q_{\mathrm{sym}}$, and the skewness of the binding energy in symmetric nuclear matter $Q_{\mathrm{sat}}$. As we are interested in the possibility of gravitational wave detection by future interferometers, we consider that the tidal interaction is the driving force for the quadrupolar nonradial fluid oscillations. We also study the correlations between those quantities, which will be useful to understand the strong physics of gravitational wave phenomena. Our main results show that $K_{\mathrm{sym}}$ impacts the frequencies of the fundamental mode mainly for low-mass neutron stars. The NEPs $Q_{\mathrm{sym}}$ and $Q_{\mathrm{sat}}$ affect the fundamental modes of intermediate and heavy neutron stars, respectively. In the case of the first pressure mode, $K_{\mathrm{sym}}$ shows a small effect, while $Q_{\mathrm{sat}}$ shows a considerable decrease in this oscillation mode independent of the neutron star mass. Similarly, for tidal deformability, the NEPs $Q_{\mathrm{sat}}$ and $Q_{\mathrm{sym}}$ show a more significant impact than $K_{\mathrm{sym}}$. Given the impact of the NEPs on gravitational wave phenomena and the currently large uncertainties of these parameters, the prospect of higher sensitivity in future gravitational wave detectors promises a possible new tool to constrain high-order NEPs.

We demonstrate that the interface between $S$-wave and $P$-wave paired superfluids in neutron stars induces a neutron supercurrent, a charge-neutral analog of the Josephson junction effect in electronic superconductors. The proton supercurrent entrainment by the neutron superfluid generates, in addition to the neutral supercurrent, a charged current across the interface. Beyond this stationary effect, the motion of the neutron vortex lines responding to secular changes in the neutron star’s rotation rate induces a time-dependent oscillating Josephson current across this interface when proton flux tubes are dragged along with them. We show that such motion produces radiation from the interface once clusters of proton flux tubes intersect the interface. The power of radiation exceeds by orders of magnitude the Ohmic dissipation of currents in neutron stars. This effect appears to be phenomenologically significant enough to heat the star and alter its cooling rate during the photon cooling era.

Future gravitational wave observatories will give us the opportunity to search for stochastic signals of astrophysical or even cosmological origins. However, parameter estimation and search will be challenging, mostly due to the overlap of multiple signal components, as well as the potentially partially unknown properties of the instrumental noise. In this work, we propose a robust statistical framework based on heavier-tailed likelihoods for the characterization of stochastic gravitational wave signals. In particular, we use the symmetric hyperbolic likelihood, which allows us to probe the signal spectral properties and simultaneously test for any departures from Gaussianity. We demonstrate this methodology with synthetic data from the future LISA mission, where we estimate the potential non-Gaussianities induced by the unresolved ultracompact Galactic binaries.

We discuss subtleties in the calculation of loop integrals in studies of hot and dense systems as they appear in both perturbative and nonperturbative approaches. To be specific, we address subtleties which appear in situations where the order of integration, differentiation, and limit processes plays a crucial role. For example, this applies to computations of the effective action and the computation of momentum-dependent correlation functions. In particular, the zero-temperature limit is delicate in systems with fermions because of the presence of discontinuities at the Fermi surface. We provide a general discussion of scenarios where the computation and evaluation of loop integrals in the context of relativistic theories requires particular attention as a change of the order of the involved mathematical operations may lead to a different result. Our general considerations are then illustrated with the aid of concrete examples, namely by the computation of masses from fully momentum-dependent correlation functions in the context of the Gross-Neveu-Yukawa model and quantum electrodynamics.

A systematic and unified analysis of the capability of lifetime frontier experiments to probe the parameter space of hypothetical long-lived particles is crucial for defining the targets of future searches. However, such a comprehensive study has not yet been conducted for dark photons—hypothetical massive particles that kinetically mix with Standard Model photons. Existing studies often rely on outdated assumptions about dark photon phenomenology, leading to inaccurate calculations of the parameter space, including regions already excluded or relevant for future experiments. In this paper, we present a comprehensive calculation of the parameter space for GeV-scale dark photons and light dark matter accessible to lifetime frontier experiments. Our analysis highlights how theoretical uncertainties in dark photon phenomenology can significantly impact experimental sensitivity across coupling and mass parameters. To facilitate further investigation, we provide these results in a publicly accessible form, incorporating updated dark photon phenomenology into the event generator senscalc.

The LHC produces an intense beam of highly energetic neutrinos of all three flavors in the forward direction, and the Forward Physics Facility (FPF) has been proposed to house a suite of experiments taking advantage of this opportunity. In this study, we investigate the FPF’s potential to probe the neutrino electromagnetic properties, including neutrino millicharge, magnetic moment, and charge radius. We find that, due to the large flux of tau neutrinos at the LHC, the FPF detectors will be able to provide more sensitive constraints on the tau neutrino magnetic moment and millicharge than previous measurements at DONUT, by searching for excess in low recoil energy electron scattering events. We also find that, by precisely measuring the rate of neutral current deep inelastic scattering events, the FPF detectors have the potential to obtain the strongest experimental bounds on the neutrino charge radius for the electron neutrino, and one of the leading bounds for the muon neutrino flavor. The same signature could also be used to measure the weak mixing angle, and we estimate that ${\sin }^2{\theta }_W$ could be measured to about 3% precision at a scale $Q\sim 10\mathrm{GeV}$, shedding new light on the longstanding NuTeV anomaly.

We outline a fundamentally quantum description of bosonic dark matter (DM) from which the conventional classical-wave picture emerges in the limit $m\ll 10\mathrm{eV}$. As appropriate for a quantum system, we start from the density matrix, which encodes the full information regarding the possible measurements we could make of DM and their fluctuations. Following fundamental results in quantum optics, we argue that for DM it is most likely that the density matrix takes the explicitly mixed form of a Gaussian over the basis of coherent states. Deviations from this would generate non-Gaussian fluctuations in DM observables, allowing a direct probe of the quantum state of DM. Our quantum optics–inspired approach allows us to rigorously define and interpret various quantities that are often only described heuristically, such as the coherence time or length. The formalism further provides a continuous description of DM through the wave-particle transition, which we exploit to study how density fluctuations over various physical scales evolve between the two limits and to reveal the unique behavior of DM near the boundary of the wave and particle descriptions.

Within the extended framework of the two-Higgs-doublet model type II (2HDM-II), enhanced by a vectorlike quark (VLQ) doublet $TB$, we present a comprehensive analysis of the process $e^{-}\gamma \to b{\nu }_e\overline{T}$ at future high-energy $e\gamma$ colliders, focusing on the decays $\overline{T}\to H^{-}\overline{b}$ and $H^{-}\to \overline{t}b$. Using current theoretical and experimental constraints, we calculate production cross sections for both unpolarized and polarized beams at center-of-mass energies of $\sqrt{s}=2$ and 3 TeV, demonstrating that polarized beams significantly enhance detection prospects by increasing production rates. By analyzing kinematic distributions, we establish optimized selection criteria to effectively separate signal events from background. At $\sqrt{s}=2\mathrm{TeV}$ with an integrated luminosity of $1500{\mathrm{fb}}^{-1}$, we find exclusion regions within $s_R^d\in [0.085,0.16]$ for $m_T\in [1000,1260]\mathrm{GeV}$ and a discovery potential within $s_R^d\in [0.14,0.17]$ for $m_T\in [1000,1100]\mathrm{GeV}$, with these regions expanding to $s_R^d\in [0.05,0.15]$ for $m_T\in [1000,1340]\mathrm{GeV}$ and $s_R^d\in [0.11,0.17]$ for $m_T\in [1000,1160]\mathrm{GeV}$ at $3000{\mathrm{fb}}^{-1}$. At $\sqrt{s}=3\mathrm{TeV}$ and $1500{\mathrm{fb}}^{-1}$, we identify exclusion regions of $s_R^d\in [0.055,0.135]$ for $m_T\in [1000,1640]\mathrm{GeV}$ and discovery regions of $s_R^d\in [0.09,0.15]$ for $m_T\in [1000,1400]\mathrm{GeV}$, which further expand to $s_R^d\in [0.028,0.12]$ for $m_T\in [1000,1970]\mathrm{GeV}$ and $s_R^d\in [0.04,0.122]$ for $m_T\in [1000,1760]\mathrm{GeV}$ at $3000{\mathrm{fb}}^{-1}$. Our findings emphasize the increased detection potential at higher center-of-mass energies, particularly at 3 TeV compared to 2 TeV, with notable improvements when polarized beams are utilized. We also account for the effects of initial state radiation, beamstrahlung, and systematic uncertainties, which influence both exclusion and discovery prospects.

We present a general analytical expression for the fixed-order structure of the distribution of a generic nonglobal observable with the $k_t$ jet algorithm at any perturbative order. This novel formulation is obtained within the framework of the eikonal approximation, assuming strong-energy ordering of emitted partons. The proposed formula is applicable to a wide range of processes at both lepton and hadron colliders.

In the framework of modular transformations, we reformulate the recently proposed hadron-quark hybrid model when the imaginary baryonic chemical potential is introduced. In this case, the number density of the hybrid model is obtained by the modular transformation of the complex number densities of the baryons (antibaryons) and the quarks (antiquarks). We can regard these number densities as the basis in the complex plane. As a result, we can consider the torus, which is characterized by the basis. Since the complex structure of the torus is invariant under the modular transformation, we can extract the topological property of the hadron-quark system using the untransformed baryon (antibaryon) and the quark (antiquark) number densities. We apply this model to analyze the Roberge-Weiss transition. It is shown that the torus vanishes at the baryonic chemical potential where the Roberge-Weiss transition appears because the number density of baryons (antibaryons) is not linearly independent of the number density of quarks (antiquarks). When the temperature $T$ is lower than the Roberge-Weiss transition temperature $T_{\mathrm{RW}}$, the torus shrinks smoothly to the one-dimensional object at the Roberge-Weiss transition point, but the discontinuity does not appear. On the other hand, the discontinuity of the geometrical object appears when $T>T_{\mathrm{RW}}$. We also calculate the modulus of the torus and transform it into the fundamental region. The transformed moduli are symmetric below $T_{\mathrm{RW}}$, but the symmetry is broken above $T_{\mathrm{RW}}$.

We present a measurement of the branching fraction and time-dependent charge-parity ($CP$) decay-rate asymmetries in $B^0\to J/\psi {\pi }^0$ decays. The data sample was collected with the Belle II detector at the SuperKEKB asymmetric $e^{+}{e}^{-}$ collider in 2019–2022 and contains $(387\pm 6)\times {10}^{6}B\overline{B}$ meson pairs from $\mathrm{\Upsilon }(4S)$ decays. We reconstruct $392\pm 24$ signal decays and fit the $CP$ parameters from the distribution of the proper-decay-time difference of the two $B$ mesons. We measure the branching fraction to be $({\mathcal{B}}^0\to J/\psi {\pi }^0)=(2.00\pm 0.12\pm 0.09)\times {10}^{-5}$ and the direct and mixing-induced $CP$ asymmetries to be $C_{CP}=0.13\pm 0.12\pm 0.03$ and $S_{CP}=-0.88\pm 0.17\pm 0.03$, respectively, where the first uncertainties are statistical and the second are systematic. We observe mixing-induced $CP$ violation with a significance of 5.0 standard deviations for the first time in this mode.

We establish a new tool for studying strongly coupled matter: an effective theory of black holes in gravity, which maps to a hydrodynamic description of field theories via the gauge-gravity duality. Our approach is inspired by previously known effective theories found in the limit of a high number of dimensions. We argue that the new approach can accurately describe phase transitions in a wide class of theories, such as the Yang-Mills and other nearly critical field theories. As an application to a previously unsolved problem, we analyze the interface between confining and deconfining phases in holographic Yang-Mills theory.

The remarkably high energies of the Large Hadron Collider (LHC) have allowed for the first measurements of the shapes and scalings of multipoint correlators of energy flow operators, $⟨\mathrm{\Psi }|\mathcal{E}({\overrightarrow{n}}_1)\mathcal{E}({\overrightarrow{n}}_2)\cdots \mathcal{E}({\overrightarrow{n}}_k)|\mathrm{\Psi }⟩$, providing new insights into the Lorentzian dynamics of quantum chromodynamics (QCD). In this letter, we use recent advances in effective field theory to derive a rigorous factorization theorem for the light-ray density matrix, $\rho =|\mathrm{\Psi }⟩⟨\mathrm{\Psi }|$, inside high transverse momentum jets at the LHC. Using the light-ray operator product expansion, the scaling behavior of multipoint correlators can be computed from the expectation value of the twist-2 spin-$J$ light-ray operators, ${\mathbb{O}}^{[J]}$, in this state, $\mathrm{Tr}[\rho {\mathbb{O}}^{[J]}]$. We compute the light-ray density matrix at next-to-leading order, and combine this with results for the next-to-leading logarithmic scaling behavior of the correlators up to six-points, comparing with CMS open data. This theoretical accuracy allows us to resolve the quantum scaling dimensions of QCD light-ray operators inside jets at the LHC. Our factorization theorem for the light-ray density matrix at the LHC completes the link between recent developments in the study of energy correlators and LHC phenomenology, opening the door to a wide variety of precision jet substructure studies.

Using $7.9\mathrm{f}{\mathrm{b}}^{-1}$ of $e^{+}{e}^{-}$ collision data collected at $\sqrt{s}=3.773\mathrm{GeV}$ with the BESIII detector at the BEPCII collider, we search for the massless dark photon with the flavor-changing neutral current processes $D^0\to \omega {\gamma }^{\prime }$ and $D^0\to \gamma {\gamma }^{\prime }$ for the first time. No significant signals are observed, and the upper limits at the 90% confidence level on the massless dark photon branching fraction are set to be $1.1\times {10}^{-5}$ and $2.0\times {10}^{-6}$ for $D^0\to \omega {\gamma }^{\prime }$ and $D^0\to \gamma {\gamma }^{\prime }$, respectively. These results provide the most stringent constraint on the new physics energy scale associated with $cu{\gamma }^{\prime }$ coupling in the world, with the new physics energy scale related parameter $|\mathbb{C}{|}^2+|{\mathbb{C}}_5{|}^2<8.2\times {10}^{-17}{\mathrm{GeV}}^{-2}$ at the 90% confidence level.

Following our previous work on hybrid quantum states in the Russo-Susskind-Thorlacius model, we study its most interesting solution representing a completely regular spacetime with the structure of causal diamond, containing an apparent horizon and radiation at infinity. Adapting recent computations of radiation entropy in terms of the entropy of entanglement, we find that this entropy follows a Page curve. This confirms our previous result [Phys. Rev. Lett. 130, 261501 (2023)], which was obtained by directly calculating the thermodynamic entropy of radiation at infinity. We also investigate the presence of a possible island in these systems and find that it does not seem to play a role in contributing to the generalized black hole entropy.

In this paper, we show how the finite formulation of quantum field theory based on Callan-Symanzik equations can be generalized to the case of nonrenormalizable theories. We derive an equation for effective action for an arbitrary single scalar field theory, allowing us to perform computations without running in intermediate divergencies. We illustrate the method with the use of $\lambda {\varphi }^4+{\varphi }^6/M^2$ theory by the explicit (and fully finite) calculations of the effective potential as well as two-, four- and six-point correlation functions at one-loop level and demonstrate that no quantum corrections to scalar mass $m^2$, depending on $M^2$ scale, are generated.

Recent detections of gravitational waves have made black hole quasinormal modes (QNM) a powerful tool in testing predictions of general relativity. Understanding the spectrum of these quasinormal modes in a broad class of theories beyond general relativity and a variety of astrophysical environments around black holes remains vital. In this work, we study the quasinormal mode spectrum of parametrized deformations of a nonrotating black hole in the vacuum. Following Vigeland and Hughes, we model these parametrized deformations as axisymmetric multipole moments in the Weyl coordinates with amplitudes much less than the amplitude of the Schwarzschild potential. These tiny bumps in the black hole geometry satisfy the linearized vacuum Einstein equations and are asymptotically flat. We use the recently developed modified Teukolsky formalism to derive one decoupled differential equation for the radiative Weyl scalar ${\mathrm{\Psi }}_0$. We then use the eigenvalue perturbation method and choose a boundary condition to compute the quasinormal mode frequency shifts of both even- and odd-parity modes with $\ell =2$, 3 and up to the overtone number $n=2$ for the Weyl multipoles with ${\ell }_W=2,3$. Our calculation provides an avenue to directly connect the multipole moments of a modified black hole spacetime to the QNM frequency shifts in a parametric way.

By constructing a model of spacetime having a strong curvature singularity in which causal geodesics are complete, but more generic causal curves are not, we explicitly show that some electrostatic field configurations on that background are bounded on every open punctured neighborhood of the curvature singularity. Our calculations are performed using the analog gravity description provided by Plebanski and Tamm, according to which the characterization of the electromagnetic field on a generic curved background is equivalent to solving Maxwell’s equations in flat space with a matter content verifying certain nontrivial constitutive relations. The regularity of the electric field as it approaches what could be considered the worst conceivable physical condition opens the door to further investigation into the possibility of propagating signals capable of crossing a spacetime singularity.

A scalar field with a timelike gradient defines a preferred slicing. This occurs even in a noncosmological setup in scalar-tensor theories such as khronometric theory. We study a black hole moving slowly relative to the preferred slicing defined by the scalar field. We consider a family of higher-order scalar-tensor theories that extend khronometric theory. The action is characterized by one constant parameter and one arbitrary function of the kinetic term of the scalar field. A slowly moving black hole is described by a dipole perturbation of a black hole at rest. We treat the metric and scalar-field perturbations consistently, derive a single master equation for the coupled system, and reconstruct the metric for a slowly moving black hole from the master variable. In this way, we revisit and generalize the previous studies. For generic theories in the family we consider, we find a solution that is regular outside the universal horizon and agnostic to the arbitrary function in the action.

Recent efforts to numerically simulate compact objects in alternative theories of gravity have largely focused on the time-evolution equations. Another critical aspect is the construction of constraint-satisfying initial data with precise control over the properties of the systems under consideration. Here, we augment the extended conformal thin sandwich framework to construct quasistationary initial data for black hole systems in scalar Gauss-Bonnet theory and numerically implement it in the open-source spectre code. Despite the resulting elliptic system being singular at black hole horizons, we demonstrate how to construct numerical solutions that extend smoothly across the horizon. We obtain quasistationary scalar hair configurations in the test-field limit for black holes with linear/angular momentum as well as for black hole binaries. For isolated black holes, we explicitly show that the scalar profile obtained is stationary by evolving the system in time and compare against previous formulations of scalar Gauss-Bonnet initial data. In the case of the binary, we find that the scalar hair near the black holes can be markedly altered by the presence of the other black hole. The initial data constructed here enable targeted simulations in scalar Gauss-Bonnet simulations with reduced initial transients.