A detailed understanding of inclusive muon neutrino charged-current interactions on argon is crucial to the study of neutrino oscillations in current and future experiments using liquid argon time projection chambers. To that end, we report a comprehensive set of differential cross section measurements for this channel that simultaneously probe the leptonic and hadronic systems by dividing the channel into final states with and without protons. Measurements of the proton kinematics and proton multiplicity of the final state are also presented. For these measurements, we utilize data collected with the MicroBooNE detector from $6.4\times {10}^{20}$ protons on target from the Fermilab booster neutrino beam at a mean neutrino energy of approximately 0.8 GeV. We present in detail the cross section extraction procedure, including the unfolding, and model validation that uses data to model comparisons and the conditional constraint formalism to detect mismodeling that may introduce biases to extracted cross sections that are larger than their uncertainties. The validation exposes insufficiencies in the overall model, motivating the inclusion of an additional data-driven reweighting systematic to ensure the accuracy of the unfolding. The extracted results are compared to a number of event generators and their performance is discussed with a focus on the regions of phase space that indicate the greatest need for modeling improvements.

A search for beyond the standard model spin-0 bosons, $\varphi$, that decay into pairs of electrons, muons, or tau leptons is presented. The search targets the associated production of such bosons with a $W$ or $Z$ gauge boson, or a top quark-antiquark pair, and uses events with three or four charged leptons, including hadronically decaying tau leptons. The proton-proton collision data set used in the analysis was collected at the LHC from 2016 to 2018 at a center-of-mass energy of 13 TeV, and corresponds to an integrated luminosity of $138{\mathrm{fb}}^{-1}$. The observations are consistent with the predictions from standard model processes. Upper limits are placed on the product of cross sections and branching fractions of such new particles over the mass range of 15 to 350 GeV with scalar, pseudoscalar, or Higgs-boson-like couplings, as well as on the product of coupling parameters and branching fractions. Several model-dependent exclusion limits are also presented. For a Higgs-boson-like $\varphi$ model, limits are set on the mixing angle of the Higgs boson with the $\varphi$ boson. For the associated production of a $\varphi$ boson with a top quark-antiquark pair, limits are set on the coupling to top quarks. Finally, limits are set for the first time on a fermiophilic dilaton-like model with scalar couplings and a fermiophilic axion-like model with pseudoscalar couplings.

We present a description of saturation in small $x$ deep inelastic scattering from power counting in a top-down effective theory derived from quantum chromodynamics (QCD). A factorization formula isolates the universal physics of the nucleus at leading power in $x$. The onset of saturation is then understood as a breakdown in the expansion in an emergent power counting parameter, which is defined by the matrix element of a gauge invariant operator. We identify a new radiation mode, which enables us to extend previous literature by distinguishing the appearance of the saturation scale from the transition to nonlinear evolution.

The anti-de-Sitter/conformal field theory (AdS/CFT) correspondence is used to provide an estimate of the radius of convergence of the linearized gradient expansion of the hydrodynamic description of $\mathcal{N}=4$ supersymmetric Yang-Mills (SYM) theory minimally coupled to $U(1)$ gauge theory subjected to strong magnetic fields. The results of this work demonstrate that the dispersion relations of hydrodynamic modes continue to converge for magnetic field strengths far beyond those values for which a hydrodynamic description is expected. For magnetic field strengths much larger then the temperature scale the bulk dual interpolates between ${\mathrm{AdS}}_{4+1}$ and the product of a Bañados-Teitelboim-Zanelli (BTZ) black hole and a two dimensional manifold (${\mathrm{BTZ}}_{2+1}\times {\mathbb{R}}^2$) and may be regarded as a renormalization group flow of the $3+1$ dimensional CFT to a $1+1$ dimensional CFT. In this regime, we clarify past literature on the quasi-normal mode (QNM) spectrum of bulk scalar fields by introducing a new way to classify the behavior of QNM collisions in the complex frequency and momentum plane.

$S$ algebra is an infinite-dimensional Lie algebra, which is known to be the symmetry algebra of some gauge theories. It is a “colored version” of the $w_{1+\infty }$. In this paper, we write down all possible $S$-invariant (celestial) operator product expansions between two positive-helicity outgoing gluons and also find the Knizhnik-Zamolodchikov type null states for these theories. Our analysis hints at the existence of an infinite number of $S$-invariant gauge theories which include the (tree-level) maximally helicity-violating sector and the self-dual Yang-Mills theory.

We extend previous efforts to quantify the entanglement generated in Hawking’s evaporation process by including rotation and thermal environments (e.g. the cosmic microwave background). Both extensions are needed to describe real black holes in our Universe. Leveraging techniques from Gaussian quantum information, we find that the black hole’s ergoregion is an active source of quantum entanglement and that thermal environments drastically degrade entanglement generation. Our predictions are suitable to be tested in the lab using analog platforms and also provide tools to assess the fate of quantum information for black holes in more generic settings.

A dipolar fixed point introduced by Aharony and Fisher is a physical example of interacting scale-invariant but nonconformal field theories. We find that the perturbative critical exponents computed in $\epsilon$ expansions violate the conformal bootstrap bound. We formulate the functional renormalization group equations à la Wetterich and Polchinski to study the fixed point. We present some results in three dimensions within (uncontrolled) local potential approximations (with or without perturbative anomalous dimensions).

Gravitational wave observations can test the validity of general relativity (GR) in the strong-field regime. Certain classes of scalar-tensor theories indeed predict that compact objects can exhibit significant deviations from their GR counterparts. Here we explore the quasinormal modes of axial perturbations in spherically symmetric black holes in three such classes: (i) dilatonic black holes with an additional scalar-Ricci coupling, (ii) spontaneously scalarized black holes with a quadratic coupling to the Gauss-Bonnet invariant and the Ricci scalar, and (iii) spontaneously scalarized black holes with a quadratic and a quartic coupling to the Gauss-Bonnet invariant.

We consider a class of finite-dimensional dynamical systems whose equations of motion are derived from a non-local-in-time action principle. The action functional has a zeroth-order piece derived from a local Hamiltonian and a perturbation in the form of a nonlocal functional of the trajectory on phase space. We prove that the dynamics of these systems admits a local Hamiltonian description to all orders in the perturbation and we provide explicit formulas for the $\mathcal{N}$th-order Hamiltonian and symplectic form in terms of the $(\mathcal{N}-1)$th-order Hamiltonian flow. In the context of general relativity, these systems arise in the study of binary systems such as pairs of black holes or neutron stars in the small mass-ratio and post-Newtonian approximations. We provide applications of the formalism to binary systems in these regimes.

The pursuit of a comprehensive theory of gravity has led to the exploration of various alternative models, necessitating a model-independent framework. The Konoplya-Rezzolla-Zhidenko (KRZ) parametrization offers a robust method for approximating stationary axisymmetric black hole spacetimes, characterized by a rapidly converging continued-fraction expansion. However, while analytical metrics benefit from this approach, numerical metrics derived from complex gravitational theories remain presenting computational challenges. Bridging this gap, we propose a method for a numerical KRZ parametrization, tested and demonstrated on pseudonumerical Kerr and Kerr-Sen spacetimes. Our approach involves constructing numerical grids to represent metric coefficients and using the grids for fitting the parameters up to an arbitrary order. We analyze the accuracy of our method across different orders of approximation, considering deviations in the metric functions and shadow images. In both Kerr and Kerr-Sen cases, we observe rapid convergence of errors with increasing orders of continued fractions, albeit with variations influenced by spin and charge. Our results underscore the potential of the proposed algorithm for parametrizing numerical metrics, offering a pathway for further investigations across diverse gravity theories.

One of the most important sources for space-borne gravitational wave detectors such as TianQin and the Laser Interferometer Space Antenna is the merger of massive black hole binaries. By analyzing the inspiral signals, we can probe the characteristics of massive black holes, including the spin-induced multipole moments. By verifying the relation among mass, spin, and quadrupole moment, the no-hair theorem can be tested. In this work, we analyzed the capability of probing the spin-induced quadrupole moment with the inspiral signal of massive black hole binaries using space-borne gravitational wave detectors. Using the Fisher information matrix, we find that the deviation of the quadrupole moment can be constrained to the level of ${10}^{-1}$, and events with higher mass ratios will provide a better constraint. We also find that the late inspiral part will dominate the result of parameter estimation. The results of Bayesian analysis indicate that the capability will be significantly enhanced by considering higher modes. We also calculate the Bayes factor, and the results indicate that the model of a black hole and a boson star can be distinguished without a doubt.

Although the constraints on general relativity (GR) from each individual gravitational wave (GW) event can be combined to form a cumulative estimate of the deviations from GR, the ever-increasing number of GW events used also leads to the ever-increasing computational cost during the parameter estimation. Therefore, in this paper, we will introduce the deviations from GR into GWs from all events in advance and then create a modified stochastic gravitational wave background (SGWB) to perform tests of GR. More precisely, we use the pSEOBNRv4HM_PA model to include the model-independent hairs and calculate the corresponding SGWB with a given merger rate. Then we turn to the Fisher information matrix to forecast the constraints on the no-hair theorem from SGWB at frequency $10\lesssim f\lesssim {10}^3\mathrm{Hz}$ detected by the third-generation ground-based GW detectors, such as the Cosmic Explorer. We find that the forecasting constraints on hairs at 68% confidence range are $\delta {\omega }_{220}=0\pm 0.1296$ and $\delta {\tau }_{220}=0\pm 0.0678$ when the flat priors about the merger rate are added, but $\delta {\omega }_{220}=0\pm 0.0903$ and $\delta {\tau }_{220}=0\pm 0.0608$ when the nonflat priors about the merger rate are added.

We report the feasibility of detecting the gravity-induced entanglement (GIE) with optomechanical systems, which is the first investigation that clarifies the feasible experimental parameters to achieve a signal-to-noise ratio of $\mathrm{S}/\mathrm{N}=1$. Our proposal focuses on GIE generation between optomechanical mirrors, coupled via gravitational interactions, under continuous measurement, feedback control, and Kalman filtering process, which matured in connection with the field of gravitational wave observations. We solved the Riccati equation to evaluate the time evolution of the conditional covariance matrix for optomechanical mirrors that estimated the minimum variance of the motions. The results demonstrate that GIE is generated faster than a well-known time scale without optomechanical coupling. The fast generation of entanglement is associated with quantum-state squeezing by the Kalman filtering process, which is an advantage of using optomechanical systems to experimentally detect GIE.

We study spherically symmetric configurations of the quadratic $f(R)$ gravity [$f(R)=R-R^2/6{\mu }^2$]. In the case of a purely gravitational system, we have fully investigated the global qualitative behavior of all static solutions satisfying the conditions of asymptotic flatness. These solutions are proved to be regular everywhere except for a naked singularity at the center; they are uniquely determined by the total mass $\mathfrak{M}$ and the “scalar charge” $Q$ characterizing the strength of the scalaron field at spatial infinity. The case $Q=0$ yields the Schwarzschild solution, but an arbitrarily small $Q\ne 0$ leads to the appearance of a central naked singularity having a significant effect on the neighboring region, even when the space-time metric in the outer region is practically insensitive to the scalaron field. Approximation procedures are developed to derive asymptotic relations near the naked singularity and at spatial infinity, and the leading terms of the solutions are presented. We have investigated the linear stability of the static solutions with respect to radial perturbations satisfying the null Dirichlet boundary condition at the center and numerically estimate the range of parameters corresponding to stable/unstable configurations. In particular, the configurations with sufficiently small $Q$ turn out to be linearly unstable.

The predicted present-day amplitude of matter fluctuations based on cosmic microwave background (CMB) anisotropy data has sometimes been found discrepant with more direct measurements of late-time structure. This has motivated many extensions to the standard cosmological model, including kinetic interactions between dark matter and dark energy (DMDE) that introduce a drag force slowing the growth of structure at late times. Exploring this scenario, we develop a model for quasilinear scales in the matter power spectrum by calculating the critical overdensity in the presence of this interaction and a varying dark energy equation of state. We explicitly avoid modeling or interpretation of data on nonlinear scales in this model (such as use of $\mathrm{\Lambda }\mathrm{CDM}$-calibrated priors), which would require numerical simulations. We find that the presence of the drag force hinders halo formation, thus increasing the deviation from $\mathrm{\Lambda }\mathrm{CDM}$ in the mildly nonlinear regime. We use CMB lensing observations from the sixth data release of the Atacama Cosmology Telescope up to $L=1250$ (in combination with Planck, Sloan Digital Sky Survey, and 6dFGS data) to derive the strongest constraints to date on the amplitude of the drag term, finding the dimensionless interaction strength ${\mathrm{\Gamma }}_{\mathrm{DMDE}}/(H_0{\rho }_{\mathrm{c}})<0.905(2.76)$ at the 68% (95%) confidence level. The inclusion of nonlinear corrections improves our constraints by about 35% compared to linear theory. Our results do not exclude the best-fit values of ${\mathrm{\Gamma }}_{\mathrm{DMDE}}$ found in previous studies using information from galaxy weak lensing, though we find no statistical preference for the dark matter–dark energy kinetic interactions over $\mathrm{\Lambda }\mathrm{CDM}$. We implement our model in a publicly available fork of the Boltzmann code class.

We consider the implications of a scalar field interacting with the dark matter fluid on the energy spectrum of primordial gravitational waves. We choose an interaction type which, before a critical matter density ${\rho }_m^c$, during the reheating era or early radiation domination era, the scalar field loses energy, transferring it to the dark matter fluid, while after the critical matter density ${\rho }_m^c$ the dark matter fluid loses energy, transferring it to the scalar field. The scalar field is assumed to have an exponential potential and at the critical matter density with ${\rho }_m\sim {\rho }_m^c$, at which point, the interaction between the scalar and the dark matter fluid is switched off, we demand that the effective equation of state of the scalar field is described by a matter dominated era. This is crucial since it affects the behavior of the trajectories and the fixed points of the two-dimensional dynamical system composed by the dark matter fluid and the scalar field. Specifically, the phase space contains two stable dark matter dominated final attractors and two unstable stiff era dominated fixed points. Thus, there exists the remarkable possibility that the Universe might feel the passing of the scalar field through the unstable kinetic dominated fixed points, during the reheating era, with the total equation of state parameter of the Universe being deformed to be larger than $w=1/3$. This deformation of the total equation of state parameter during the reheating era can potentially have significant effects on the energy spectrum of primordial gravitational waves. The model we use also contains an $F(R)$ gravity that controls in a dominant way inflation and the late-time acceleration, in a phenomenologically viable way.

Mature neutron stars are thought to be sufficiently cold that nuclei in the outer layers freeze, solidifying a crust. Crustal elasticity allows the star to support a set of seismic modes, such as torsional oscillations. These axial-parity modes can couple to the polar sector in a number of ways, for example via rotation or a magnetic field. Even in a static, spherically symmetric star, however, these modes can couple at nonlinear order. In this study, such couplings in the crust are examined for the first time: we derive the axisymmetric perturbation equations for second-order axial eigenfunctions, which are sourced by axial-polar couplings at first order, and solve the resulting equations in the time domain. Through our studies, we find that the second-order spectrum contains additional oscillation modes, not predicted by the linear analysis with either axial or polar perturbations, which can be excited to relatively large amplitudes.

Thermal noise in the mirror coatings limits the accuracy of today’s most optical precision measurement experiments. Unlike the more commonly discussed thermal phase noise, the crystalline coating can generate thermal birefringent noise due to its anisotropic nature. In this study, we propose that the nondiagonal anisotropic photoelastic effect induced by the Brownian motion of mirror coating layers may contribute to this noise. Employing a standard model for the coating surface, we calculate the spectrum of the nondiagonal anisotropic Brownian photoelastic noise to be $1.2\times {10}^{-11}{p}_{63}{f}^{-1/2}/{\mathrm{Hz}}^{1/2}$. Further experiments are warranted to validate the influence of this effect and reduce its uncertainty. Our findings highlight that for high-precision experiments involving optical resonant cavities targeting signals imprinted in optical polarizations, this noise could emerge as a limiting factor for experimental sensitivity.

We report the first experimental results obtained with the new haloscope of the QUAX experiment located at Laboratori Nazionali di Frascati of INFN (LNF). The haloscope is composed of a OFHC Cu resonant cavity cooled down to about 30 mK and immersed in a magnetic field of 8 T. The cavity frequency was varied in a 6 MHz range between 8.831496 and 8.83803 GHz. This corresponds to a previously unprobed mass range between 36.52413 and $36.5511\mathrm{\mu }\mathrm{eV}$. We don’t observe any excess in the power spectrum and set limits on the axion-photon coupling in this mass range down to $g_{a\gamma \gamma }<0.882\times {10}^{-13}{\mathrm{GeV}}^{-1}$ with the confidence level set to 90%.

The conventional Passarino-Veltman reduction is a systematic procedure based on the Lorentz covariance, which can efficiently reduce the one-loop tensor Feynman integrals in the relativistic quantum field theories (QFTs) at zero temperature and zero density. However, the Lorentz covariance is explicitly broken when either of the temperature and density is finite, due to a rest reference frame of the many-body system in which the temperature and density are measured, rendering the conventional Passarino-Veltman reduction not applicable anymore to reduce the one-loop tensor Feynman integrals therein. In this paper, we report a generalized Passarino-Veltman reduction which can efficiently simplify the one-loop tensor Feynman integrals in the relativistic QFTs at finite temperature and/or finite density. The generalized Passarino-Veltman reduction can analyze the one-loop tensor Feynman integrals in a wide range of physical systems described by the relativistic QFTs at finite temperature and/or finite density, such as quark-gluon plasma in nuclear physics.