Natural supersymmetry (SUSY) with light Higgsinos is perhaps the most plausible of all weak scale SUSY models while a variety of motivations point to (right) tau sleptons as the lightest of all the sleptons. We examine a SUSY model line with rather light right staus embedded within natural SUSY. For light ${\tilde{\tau }}_1$ of a few hundred GeV, the decays ${\tilde{\tau }}_1\to \tau {\tilde{\chi }}_{1,2}^0$ and ${\nu }_{\tau }{\tilde{\chi }}_1^{-}$ occur at comparable rates where the (Higgsino-like) ${\tilde{\chi }}_1^{\pm }$ and ${\tilde{\chi }}_2^0$ release only small visible energy: in this case, the expected ${\tau }^{+}{\tau }^{-}+{\cancel{E}}_T$ signature is diminished from the usual expectations due to the presence of the nearly invisible decay mode ${\tilde{\tau }}_1\to {\nu }_{\tau }{\tilde{\chi }}_1^{-}$. However, once $m_{{\tilde{\tau }}_1}\gtrsim m(bino)$, decays to binos such as ${\tilde{\tau }}_1\to \tau {\tilde{\chi }}_3^0$ open up where ${\tilde{\chi }}_3^0$ decays to Higgsinos plus $W^{\pm }$, $Z^0$, and $h$ at comparable rates. For these heavier staus, the stau pair production gives rise to $\text{diboson}+{\cancel{E}}_T$ events, which may contain 0, 1, or 2 additional hard $\tau$ leptons. From these considerations, we examine the potential for future discovery of tau-slepton pair production at a high-luminosity LHC. While we do not find a $5\sigma$ HL-LHC discovery reach for $3000{\mathrm{fb}}^{-1}$, we do find a 95% CL exclusion reach, ranging between $m_{{\tilde{\tau }}_1}:100–450\mathrm{GeV}$ for $m_{{\tilde{\chi }}_1^0}\sim 100\mathrm{GeV}$. This latter reach disappears for $m_{{\tilde{\chi }}_1^0}\gtrsim 200\mathrm{GeV}$.

By considering baryons as clusters of three quarks, we extend the Nambu-Jona-Lasinio model to describe baryonic matter, quark matter, and their transitions in a unified manner, where the Dirac sea and spontaneous chiral symmetry breaking are considered. In particular, a density-dependent structural function ${\alpha }_S$ is introduced to modulate the four(six)-point interaction strengths to reproduce the baryon masses in vacuum and medium. Vector interactions are considered with the exchange of $\omega$ and $\rho$ mesons, where the density-dependent coupling constants are fixed by reproducing nuclear matter properties as well as the $\mathrm{\Lambda }$-hyperon potential depth in nuclear medium. As density increases, quarks will emerge as quasifree particles and coexist with baryons. This phase is interpreted as quarkyonic matter, where quarks are restricted to the lowest energy states in the presence of baryons, i.e., quarks are still confined. Similar to the treatment of $\alpha$ clustering in nuclear medium, a Pauli blocking term is added to baryon masses so that baryons eventually become unbound in the presence of a quark Fermi sea. Then at large enough densities baryons vanish and a Mott transition takes place, we consider such a transition as deconfinement phase transition. Depending on the strengths of Pauli blocking term and quark-vector meson couplings, both first-order and continues phase transitions are observed for quarkyonic, chiral, and deconfinement phase transitions. The corresponding compact star structures are then investigated and confronted with various astrophysical constraints.

We have investigated the $qss\overline{q}q$ ($q=u$ or $d$) system to find possible pentaquark explanations for the $\mathrm{\Xi }$ resonances. The bound state calculation is carried out within the framework of the quark delocalization color screening model. The scattering processes are also studied to examine the possible resonance states. The current results indicate that the $\mathrm{\Xi }(1950)$ state can be interpreted as a $\mathrm{\Lambda }{\overline{K}}^{*}$ state with $J^P=1/2^{-}$. Three states are identified that match the $\mathrm{\Xi }(2250)$, which are a ${\mathrm{\Sigma }}^{*}{\overline{K}}^{*}$ state with $J^P=3/2^{-}$, a ${\mathrm{\Sigma }}^{*}{\overline{K}}^{*}$ state with $J^P=5/2^{-}$, and a ${\mathrm{\Xi }}^{*}\rho$ state with $J^P=5/2^{-}$. This may explain the conflicting experimental values for the width of the $\mathrm{\Xi }(2250)$ state. A new $\mathrm{\Xi }$ resonance is predicted, whose mass and width are 2066–2079 MeV and 186–189 MeV, respectively. These results contribute to understanding the nature of the $\mathrm{\Xi }$ resonances and to the future search for new $\mathrm{\Xi }$ resonances. Moreover, it is meaningful to further investigate the $\mathrm{\Xi }$ resonances from an unquenched picture on the basis of pentaquark investigation.

We investigate the structure of ground-state heavy mesons within the light-front quark model, utilizing wave functions derived from the single Gaussian ansatz (SGA) and the Gaussian expansion method (GEM). By performing a ${\chi }^2$ fit to static properties such as mass spectra and decay constants, we determine the model parameters for each approach. We then compare the impacts of both methods on the light-front wave functions and structural observables. Our analysis reveals significant differences in the distribution amplitudes ${\varphi }_{2;M}(x)$ near the end points, with GEM showing enhanced amplitudes and correct asymptotic behavior ${\varphi }_{2;M}(x\to 1)\propto (1-x)$, consistent with perturbative QCD. This end point behavior is linked to the short-range (high-momentum) wave function governed by color Coulomb interaction and relativistic kinematics. GEM accurately reproduces a power-law damping ${\psi }_0(k\to \infty )\propto 1/k_{\perp }^2$, aligning with perturbative QCD predictions. Furthermore, the electromagnetic form factors of pseudoscalar mesons in the low-$Q^2$ region fall off faster with GEM than with SGA. Overall, while both methods adequately describe static properties, GEM provides a more accurate description of structural properties, being more sensitive to details and asymptotic behaviors.

At leading order in weak and electromagnetic couplings, cross sections for (anti)neutrino-nucleon elastic scattering are determined by four nucleon form factors that depend on the momentum transfer $Q^2$. Including radiative corrections in the Standard Model and potential new physics contributions beyond the Standard Model, eight invariant amplitudes are possible, depending on both $Q^2$ and the (anti)neutrino energy $E_{\nu }$. We review the definition of these amplitudes and use them to compute both unpolarized and polarized observables including radiative corrections. We show that unpolarized accelerator neutrino cross-section measurements can probe new physics parameter space within the constraints inferred from precision beta decay measurements.

We perform global fits of the Higgs boson couplings to the full Higgs datasets collected at the LHC with the integrated luminosities per experiment of approximately $5/\mathrm{fb}$ at 7 TeV, $20/\mathrm{fb}$ at 8 TeV, and up to $139/\mathrm{fb}$ at 13 TeV. Our combined analysis based on the experimental signal strengths used in this work and the theoretical ones elaborated for our analysis reliably reproduce the results in the literature. We reveal that the LHC Higgs precision data are no longer best described by the Standard Model (SM) Higgs boson taking account of extensive and comprehensive $CP$-conserving and $CP$-violating scenarios found in several well-motivated models beyond the SM. Especially, in most of the fits considered in this work, we observe that the best-fitted values of the normalized Yukawa couplings are about $2\sigma$ below the corresponding SM ones with the $1\sigma$ errors of 3%–5%. On the other hand, the gauge-Higgs couplings are consistent with the SM with the $1\sigma$ errors of 2%–3%. Incidentally, the reduced Yukawa couplings help to explain the excess of the $H\to Z\gamma$ signal strength of $2.2\pm 0.7$ recently reported by the ATLAS and CMS collaborations.

A search is presented for high-mass exclusive diphoton production via photon-photon fusion in proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$ in events where both protons survive the interaction. The analysis utilizes data corresponding to an integrated luminosity of $103{\mathrm{fb}}^{-1}$ collected in 2016–2018 with the central CMS detector and the CMS and TOTEM precision proton spectrometer (PPS). Events that have two photons with high transverse momenta ($p_{\mathrm{T}}^{\gamma }>100\mathrm{GeV}$), back-to-back in azimuth, and with a large diphoton invariant mass ($m_{\gamma \gamma }>350\mathrm{GeV}$) are selected. To remove the dominant inclusive diphoton backgrounds, the kinematic properties of the protons detected in PPS are required to match those of the central diphoton system. Only events having opposite-side forward protons detected with a fractional momentum loss between 0.035 and 0.15 (0.18) for the detectors on the negative (positive) side of CMS are considered. One exclusive diphoton candidate is observed for an expected background of 1.1 events. Limits at 95% confidence level are derived for the four-photon anomalous coupling parameters $|{\zeta }_1|<0.073{\mathrm{TeV}}^{-4}$ and $|{\zeta }_2|<0.15{\mathrm{TeV}}^{-4}$, using an effective field theory. Additionally, upper limits are placed on the production of axionlike particles with coupling strength to photons $f^{-1}$ that varies from $0.03{\mathrm{TeV}}^{-1}$ to $1{\mathrm{TeV}}^{-1}$ over the mass range from 500 to 2000 GeV.

Daya Bay presents the first measurement of cosmogenic ${}^8\mathrm{He}$ isotope production in liquid scintillator, using an innovative method for identifying cascade decays of ${}^8\mathrm{He}$ and its child isotope, ${}^8\mathrm{Li}$. We also measure the production yield of ${}^9\mathrm{Li}$ isotopes using well-established methodology. The results, in units of ${10}^{-8}{\mu }^{-1}{\mathrm{g}}^{-1}{\mathrm{cm}}^2$, are $0.307\pm 0.042$, $0.341\pm 0.040$, and $0.546\pm 0.076$ for ${}^8\mathrm{He}$, and $6.73\pm 0.73$, $6.75\pm 0.70$, and $13.74\pm 0.82$ for ${}^9\mathrm{Li}$ at average muon energies of 63.9 GeV, 64.7 GeV, and 143.0 GeV, respectively. The measured production rate of ${}^8\mathrm{He}$ isotopes is more than an order of magnitude lower than any other measurement of cosmogenic isotope production. It replaces the results of previous attempts to determine the ratio of ${}^8\mathrm{He}$ to ${}^9\mathrm{Li}$ production that yielded a wide range of limits from 0% to 30%. The results provide future liquid-scintillator-based experiments with improved ability to predict cosmogenic backgrounds.

The effect of noise induced by gravitons has been investigated using a Bose-Einstein condensate. The general complex scalar field theory with a quadratic self-interaction term has been considered in the presence of a gravitational wave. The gravitational wave perturbation is then considered as a sum of discrete Fourier modes in the momentum space. Varying the action and making use of the principle of least action, one obtains two equations of motion corresponding to the gravitational perturbation and the time-dependent part of the pseudo-Goldstone boson. Coming to an operatorial representation and quantizing the phase space variables via appropriately introduced canonical commutation relations between the canonically conjugate variables corresponding to the graviton and bosonic part of the total system, one obtains a proper quantum gravity setup. Then we obtain the Bogoliubov coefficients from the solution of the time-dependent part of the pseudo-Goldstone boson and construct the covariance metric for the bosons initially being in a squeezed state. The entries of the covariance matrix now involves a stochastic contribution which results in an operatorial stochastic structure of the quantum Fisher information. Using the stochastic average of the Fisher information, we obtain a lower bound on the amplitude parameter of the gravitational wave. As the entire calculation is done at zero temperature, the bosonic system, by construction, will behave as a Bose-Einstein condensate. For a Bose-Einstein condensate with a single mode, we observe that the lower bound of the expectation value of the square of the uncertainty in the amplitude measurement does not become infinite when the total observational term approaches zero. It always has a finite value if the gravitons are initially in a squeezed state with high enough squeezing. In order to sum over all possible momentum modes, we next consider a noise term with a suitable Gaussian weight factor which decays over time. We then obtain the lower bound on the final expectation value of the square of the variance in the amplitude parameter. Because of the noise induced by the graviton, there is a minimum value of the measurement time below which it is impossible to detect any gravitational wave using a Bose-Einstein condensate. Finally, we consider interaction between the phonon modes of the Bose-Einstein condensate which results in a decoherence. We observe that the decoherence effect becomes significant for gravitons with minimal squeezing.

Geometrical properties of spacetime are difficult to study in nonperturbative approaches to quantum gravity like causal dynamical triangulations (CDT), where one uses simplicial manifolds to define the gravitational path integral, instead of Riemannian manifolds. In particular, in CDT one only relies on two mathematical tools, a distance measure and a volume measure. In this paper, we define a notion of scalar curvature, for metric spaces endowed with a volume measure or a random walk, without assuming nor using notions of tensor calculus. Furthermore, we directly define the Ricci scalar, without the need of defining and computing the Riemann or the Ricci tensor a priori. For this, we make use of quantities, like the surface of a geodesic sphere, or the return probability of scalar diffusion processes, that can be computed in these metric spaces, as in a Riemannian manifold, where they receive scalar curvature contributions. Our definitions recover the classical results of scalar curvature when the sets are Riemannian manifolds. We propose two methods to compute the scalar curvature in these spaces, and we compare their features in natural implementations in discrete spaces. The defined generalized scalar curvatures are easily implemented on discrete spaces, like graphs. We present the results of our definitions on random triangulations of a 2D sphere and plane. Additionally, we show the results of our generalized scalar curvatures on the quantum geometries of 2D CDT, where we find that all our definitions indicate a flat ground state of the gravitational path integral.

The large-charge master field which generates all $n$-point correlation functions with an insertion of large charge $Q$ in nonrelativistic conformal field theory is obtained. This field is used to compute Schrödinger-invariant $n$-point correlation functions of large-charge operators via a direct evaluation of the path integral. Conformal dimensions are found to agree with calculations based on the state-operator correspondence. The master field solution exhibits an emergent harmonic trap whose frequency is a function of the Euclidean time. The large-charge effective action with operator insertions describes a droplet of superfluid matter whose spatial size scales with the time separation of sources. The solution is used to compute Schrödinger symmetry breaking corrections in the large-charge effective field theory (EFT) due to a finite scattering length in the fundamental theory of fermions near unitarity. The scaling of these effects in the large-charge power counting scheme is established, and the size of the effects is quantified using input from quantum Monte Carlo simulations of the near-unitary gas, as well as from the large-$N$ expansion at large charge.

Inspired by the method of smoothed asymptotics developed by Terence Tao, we introduce a new ultraviolet regularization scheme for loop integrals in quantum field theory which we call $\eta$ regularization. This reveals a connection between the elimination of divergences in divergent series of powers and the preservation of gauge invariance in the regularization of loop integrals in quantum field theory. In particular, we note that a method for regularizing the series of natural numbers so that it converges to minus one-twelfth inspires a regularization scheme for non-Abelian gauge theories coupled to Dirac fermions that preserves the Ward identity for the vacuum polarization tensor and other higher point functions. We also comment on a possible connection to Schwinger proper time integrals.

The parametrized post-Einsteinian (ppE) framework and its variants are widely used to probe gravity through gravitational-wave tests that apply to a large class of theories beyond general relativity. However, the ppE framework is not truly theory-agnostic as it only captures certain types of deviations from general relativity: those that admit a post-Newtonian series representation in the inspiral of coalescing compact objects. Moreover, each type of deviation in the ppE framework has to be tested separately, making the whole process computationally inefficient and expensive, possibly obscuring the theoretical interpretation of potential deviations that could be detected in the future. We here present the neural post-Einsteinian (npE) framework, an extension of the ppE formalism that overcomes the above weaknesses using deep-learning neural networks. The core of the npE framework is a variational autoencoder that maps the discrete ppE theories into a continuous latent space in a well-organized manner. This design enables the npE framework to test many theories simultaneously and to select the theory that best describes the observation in a single parameter estimation run. The smooth extension of the ppE parametrization also allows for more general types of deviations to be searched for with the npE model. We showcase the application of the new npE framework to future tests of general relativity with the fifth observing run of the LIGO-Virgo-KAGRA collaboration. In particular, the npE framework is demonstrated to efficiently explore modifications to general relativity beyond what can be mapped by the ppE framework, including modifications coming from higher-order curvature corrections to the Einstein-Hilbert action at high post-Newtonian order, and dark-photon interactions in possibly hidden sectors of matter that do not admit a post-Newtonian representation.

It was recently found that the optical field fluctuations in self-defocusing media can be described by sound waves propagating in a two-dimensional photon fluid. This photon fluid is controlled by the driving beam and serves as the background in which the sound waves can experience an effective curved spacetime, such that it provides a new platform of studying analog black holes. In this paper, we are interested in investigating the quasinormal modes of this analog black hole in the photon-fluid model. Based on the master equation of motion of the optical field fluctuations, we calculate the frequencies of quasinormal modes (QNF) with three different numerical methods to make sure the QNF we get are reliable. Besides fundamental modes, we also try to calculate the overtones up to $n=3$ aiming to uncover more properties of QNF. The effects of angular velocity ${\mathrm{\Omega }}_H$ of the black hole, the overtone number $n$ and the winding number $m$ on the QNF are investigated. Under the $m$ with opposite sign, we find that both the real and imaginary part of the QNF will show strikingly contrasting behaviors when the QNF is plotted against ${\mathrm{\Omega }}_H$, and the similar contrast effects are also found when comparing the influences from winding number and overtone number. We hope that this work may potentially contribute to the future detections of quasinormal modes in experimental settings of photon fluid.

In this article, we discuss the effect of light, nongauge, bosonic degrees of freedom on the exterior spacetime of an exotic compact object. We show that such fields generically introduce large deviations from black hole spacetimes of general relativity near and outside the surfaces of ultracompact exotic objects unless one assumes they totally decouple from the standard model or new heavy fields. Hence, using black hole spacetimes of general relativity to model ultracompact exotic objects and their perturbations relies implicitly on this assumption or on the absence of such fields.

One of the most promising avenues to perform numerical evolutions in theories beyond general relativity is the fixing-the-equations approach, a proposal in which new “driver” equations are added to the evolution equations in a way that allows for stable numerical evolutions. In this direction, we extend the numerical relativity code spectre to evolve a “fixed” version of scalar Gauss-Bonnet theory in the decoupling limit, a phenomenologically interesting theory that allows for hairy black hole solutions in vacuum. We focus on isolated black hole systems both with and without linear and angular momentum, and propose a new driver equation to improve the recovery of such stationary solutions. We demonstrate the effectiveness of the latter by numerically evolving black holes that undergo spontaneous scalarization using different driver equations. Finally, we evaluate the accuracy of the obtained solutions by comparing with the original unaltered theory.

Fuzzy dark matter (FDM) is an intriguing candidate alternative to the standard cold dark matter (CDM). The FDM model predicts that dark halos have characteristic core structures generated by the effect of quantum pressure, which is different from the structure of CDM halos. We devise a semianalytic model of an FDM halo density profile by assuming that the density distribution results from the redistribution of mass in a halo with the Navarro–Frenk–White profile. We calculate the mass redistribution radius by considering dynamical relaxation within the FDM halo. We adopt a concentration-halo mass relation with lower concentration compared to that in the CDM model below the half mode mass, which originates from the suppressed matter density fluctuations at small length scales. Our model reproduces the core-halo mass relation (CHMR) found in the numerical simulation of Schive et al. [Nat. Phys. 10, 496 (2014).] at $z<1$. We show that the CHMR is well described by a double power law, unlike previous studies that approximate it by a single power law. Our model predictions are in reasonable agreement with the results of the largest FDM simulation of May and Springel [Mon. Not. R. Astron. Soc. 506, 2603 (2021).] at $z=3$. We find that the core mass for a given halo mass follows the log-normal distribution, both in our model and in the simulation results for the first time, and quantitatively compare the variance of the distribution among them. Although our model does not fully explain the scatter of the CHMR, we show the scatter of the concentration-halo mass relation sizably contributes to them.

We present self-consistent numerical simulations in general relativity of putative primordial black holes inside neutron stars. Complementing a companion paper in which we assumed the black-hole mass $m$ to be much smaller than the mass $M_{*}$ of the neutron star, thereby justifying a point-mass treatment, we here consider black holes with masses large enough so that their effect on the neutron star cannot be neglected. We develop and employ several new numerical techniques, including initial data describing boosted black holes in neutron-star spacetimes, a relativistic determination of the escape speed, and a gauge condition that keeps the black hole at a fixed coordinate location. We then perform numerical simulations that highlight different aspects of the capture of primordial black holes by neutron stars. In particular, we simulate the initial passage of the black hole through the star, demonstrating that the neutron star remains dynamically stable provided the black-hole mass is sufficiently small, $m\lesssim 0.05M_{*}$. We model the late evolution of a black hole oscillating about the center of an initially stable neutron star while accreting stellar mass and ultimately triggering gravitational collapse.

Many gravitational wave (GW) sources are expected to have non-negligible eccentricity in the millihertz band. These highly eccentric compact object binaries may commonly serve as a progenitor stage of GW mergers, particularly in dynamical channels where environmental perturbations bring a binary with large initial orbital separation into a close pericenter passage, leading to efficient GW emission and a final merger. This work examines the stochastic GW background from highly eccentric ($e\gtrsim 0.9$), stellar-mass sources in the mHz band. Our findings suggest that these binaries can contribute a substantial GW power spectrum, potentially exceeding the LISA instrumental noise at $\sim 3–7\mathrm{mHz}$. This stochastic background is likely to be dominated by eccentric sources within the Milky Way, thus introducing anisotropy and time dependence in LISA’s detection. However, given efficient search strategies to identify GW transients from highly eccentric binaries, the unresolvable noise level can be substantially lower, approaching $\sim 2$ orders of magnitude below the LISA noise curve. Therefore, we highlight the importance of characterizing stellar-mass GW sources with extreme eccentricity, especially their transient GW signals in the millihertz band.

The internal structure and abundance of dark matter halos and subhalos are powerful probes of the nature of dark matter. In order to compare observations with dark matter models, accurate theoretical predictions of these quantities are needed. We present a fast and accurate method to describe the tidal evolution of subhalos within their parent halo, based on a semianalytic approach. We first consider idealized $N$-body simulations of subhalos within their host halo, using a generalized mass density profile that describes their properties in a variety of dark matter models at infall, including popular warm, cold, and self-interacting ones. Using these simulations we construct tidal “tracks” for the evolution of subhalos based on their conditions at infall. Second, we use the results of these simulations to build semianalytic models for tidal effects, including stripping and heating and implement them within the code galacticus. Our semianalytic models can accurately predict the tidal evolution of both cored and cuspy subhalos, including the bound mass and density profiles, providing a powerful and efficient tool for studying the postinfall properties of subhalos in different dark matter models.