Within the isolated horizon formalism, we investigate a static axisymmetric space-time of a black hole influenced by matter in its neighborhood. To illustrate the role of ingredients and assumptions in this formalism, we first show how, in spherical symmetry, the field equations and gauge conditions imply the isolated horizon initial data leading to the Schwarzschild space-time. Then, we construct the initial data for a static axisymmetric isolated horizon representing a deformed black hole. The space-time description in the Bondi-like coordinates is then found as a series expansion in the vicinity of the horizon. To graphically illustrate this construction, we also find a numerical solution for a black hole deformed by a particular analytic model of a thin accretion disk. We also discuss how an accretion disk affects the analytical properties of the horizon geometry.

Gravitational wave (GW) detection is of paramount importance in fundamental physics and GW astronomy, yet it presents formidable challenges. One significant challenge is the removal of noise transient artifacts known as “glitches,” which greatly impact the search and identification of GWs. Recent research has achieved remarkable results in data denoising, often using effective modeling methods to remove glitches. However, for glitches from uncertain or unknown sources, current methods cannot completely eliminate them from the GW signal. In this work, we leverage the inherent robustness of machine learning to obtain reliable posterior parameter distributions directly from GW data contaminated by glitches. Our network model provides reasonable and rapid parameter inference even in the presence of glitches, without needing to remove them. We also investigate various factors affecting the rationality of parameter inference in our normalizing flow network, including glitch and GW parameters. The results demonstrate that the normalizing flow can reasonably infer the source parameters of GWs even with unknown contamination. We find that the nature of the glitch itself is the only factor that can affect the rationality of the inferred results. With improvements to our model, we anticipate accelerating the localization of electromagnetic counterparts and providing priors for more accurate deglitching, thereby speeding up subsequent data processing procedures.

Recent observations of two nearby black hole low-mass x-ray binaries have suggested possible indication of dark matter density spikes. While the evidence is compelling, one issue with this interpretation is that light black holes formed from stellar collapse are not expected to form dark matter spikes, and so it is unclear how the stellar-mass black holes in these binaries could have acquired such features. Since primordial black holes are expected to form ultradense dark matter minispikes, in this article we explore the possibility of a primordial origin for these light black holes.

We investigate the impact of the Dark Energy Spectroscopic Instrument (DESI) 2024 data on dark energy scenarios. We thus analyze three typologies of models, the first in which the cosmic speedup is related to thermodynamics and the second associated with Taylor expansions of the barotropic factor, whereas the third is based on ad hoc dark energy parametrizations. In this respect, we first work at the background, inferring a posteriori kinematic quantities associated with each model. Afterward, we obtain early-time predictions, computing departures on the growth evolution with respect to the model that better fits DESI data. We find that—depending on the combination of catalogs hereby considered, but independently from whether a debated data point placed at $z=0.51$ is removed or not—the best model to fit data is not the Chevallier-Polarski-Linder (CPL) parametrization but rather a more complicated log-corrected dark energy contribution or the $\mathrm{\Lambda }\mathrm{CDM}$ model, indicating that the possible tension between the concordance paradigm and the CPL model can be severely alleviated. We conclude that future data points will be essential to clarify whether dynamical dark energy is really in tension with the $\mathrm{\Lambda }\mathrm{CDM}$ model.

Tornadoes are severe weather phenomena characterized by a violently rotating column of air connecting the ground to a parent storm. Within the United States, hundreds of tornadoes occur every year. Despite this, the dynamics of tornado formation and propagation are not particularly well understood, in part due to the challenge of instrumentation: many existing instruments for measuring atmospheric properties are in-situ detectors, making deployment in or near an active or developing tornado difficult. Here, we combine local atmospheric and cosmic ray air shower simulation to explore the potential for remote measurement of the density field within tornado-producing supercell thunderstorms by examining directional variations of the atmospheric muon flux.

Recent studies have revealed that certain nuclear parameters are more dominant than others in governing global neutron star properties, such as its structure or oscillation mode characteristics. Although neutron stars can in general be assumed to be cold, in astrophysical scenarios such as newly born neutron stars or remnants of binary neutron star mergers, finite temperature effects play a non-negligible role. In this work, we perform a consistent and systematic investigation of the role of nuclear parameters and thermal effects on neutron star properties and fluid oscillation modes within a full general relativistic scheme. We impose constraints on the parameter space of the relativistic mean field model using state-of-the-art information from terrestrial experiments and multimessenger astrophysical data. We find effective nucleon mass to be the most important nuclear parameter controlling astrophysical observables of hot neutron stars, similar to the cold beta equilibrated matter. However, we conclude that the interplay among saturation properties and astrophysical observables depends not only on the thermal configurations considered but also on the constraints imposed. We also investigated the role of nuclear saturation parameters on some universal relations for hot neutron stars which are important in gravitational wave asteroseismology. Our investigation confirmed that these relations are mostly insensitive to nuclear saturation properties and mainly affected by variation of charge fraction in the star.

Dark matter substructures emerge naturally in axion cosmology. The DALI experiment is a next-generation interferometer for wavelike dark matter in the $25–250\mathrm{\mu eV}$ range, currently in its prototyping phase. Although DALI’s main objective is to explore the dark matter in our galaxy as a haloscope, to a large degree in this article we explore the prospect for detection of fine grained streams made of axions that would enter the Solar System, as suggested by previous work, which would be performed in parallel without interfering with the search for virialized axions. We find that DALI will have a sensitivity to encounters with these coherent streams that fully spans the window defined by the coupling strength to photons of representative axion models over a stacked bandwidth of two decades in mass.

We present our new general relativistic Monte Carlo (MC)-based neutrino radiation hydrodynamics code designed to solve axisymmetric systems with several improvements. The main improvements are as follows: (i) the development of an extended version of the implicit MC method for multispecies radiation fields; (ii) modeling of neutrino pair process rates based on a new numerically efficient and asymptotically correct fitting function for the kernel function; (iii) the implementation of new numerical limiters on the radiation-matter interaction to ensure a stable and physically correct evolution of the system. We apply our code to a black hole (BH)-torus system with a BH mass of $3M_{\odot }$, BH dimensionless spin of 0.8, and a torus mass of $0.1M_{\odot }$, which mimics a postmerger remnant of a binary neutron star merger in the case that the massive neutron star collapses to a BH within a short timescale ($\sim 10\mathrm{ms}$). We follow the evolution of the BH-torus system up to more than 1 s with our MC-based radiation viscous-hydrodynamics code that dynamically takes into account nonthermal pair annihilation. We find that the system evolution and the various key quantities, such as neutrino luminosity, ejecta mass, torus $Y_e$, and pair annihilation luminosity, are broadly in agreement with the results of the previous studies. We also find that the ${\nu }_e{\overline{\nu }}_e$ pair annihilation can launch a relativistic outflow for a timescale of $\sim 0.1\mathrm{s}$, and it can be energetic enough to explain some of short-hard gamma-ray bursts and the precursors. Finally, we calculate the indicators of the fast flavor instability directly from the obtained neutrino distribution functions, which indicate that the instability can occur particularly near the equatorial region of the torus.

Super-Kamiokande’s spallation backgrounds—the delayed beta decays of nuclides following cosmic-ray muons—are nearly all produced by the small fraction of muons with hadronic showers. We show that these hadronic showers also produce neutrons; their captures can be detected with high efficiency due to the recent addition of dissolved gadolinium to Super-Kamiokande. We show that new cuts based on the neutron tagging of showers could reduce spallation backgrounds by a factor of at least four beyond present cuts. With further work, this could lead to a near elimination of detector backgrounds above about 6 MeV, which would significantly improve the sensitivity of Super-Kamiokande. These findings heighten the importance of adding gadolinium to Hyper-Kamiokande, which is at a shallower depth. Further, a similar approach could be used in other detectors, for example, the JUNO liquid-scintillator detector, which is also at a shallower depth.

The production of black holes with masses between $\sim 50M_{\odot }-130M_{\odot }$ is believed to be prohibited by stellar processes due to (pulsational) pair-instability supernovae. Hierarchical mergers of black holes in dense star clusters are proposed as a mechanism to explain the observations of binary black holes with component masses in this range by LIGO/Virgo. We study the efficiency with which hierarchical mergers can produce higher and higher masses using a simple model of the forward evolution of binary black hole populations in gravitationally bound systems like stellar clusters. The model relies on pairing probability and initial mass functions for the black hole population, along with numerical relativity fitting formulas for the mass, spin, and kick speed of the merger remnant. We carry out an extensive comparison of the predictions of our model with clusterBHBdynamics (cBHBD) model, a fast method for the evolution of star clusters and black holes therein. For this comparison, we consider three different pairing functions of black holes and consider simulations from high- and low-metallicity cluster environments from cBHBD. We find good agreements between our model and the cBHBD results when the pairing probability of binaries depends on both total mass and mass ratio. We also assess the efficiency of hierarchical mergers as a function of merger generation and derive the mass distribution of black holes using our model. We find that the multimodal features in the observed binary black hole mass spectrum—revealed by the nonparametric population models—can be interpreted by invoking the hierarchical merger scenario in dense, metal-rich, stellar environments. Further, the two subdominant peaks in the GWTC-3 component mass spectrum are consistent with second and third-generation mergers in metal-rich, dense environments. With more binary black hole detections, our model could be used to infer the black hole initial mass function and pairing probability exponents.

Charged current interactions of neutrinos inside the Earth can result in secondary muons and $\tau$-leptons which are detectable by several existing and planned neutrino experiments through a wide variety of event topologies. Consideration of such events can improve detector performance and provide unique signatures which help with event reconstruction. In this work, we describe NuLeptonSim, a propagation tool for neutrinos and charged leptons that builds on the fast NuTauSim framework. NuLeptonSim considers energy losses of charged leptons, modeled both continuously for performance or stochastically for accuracy, as well as interaction models for all flavors of neutrinos, including the Glashow resonance. We demonstrate the results from including these effects on the Earth emergence probability of various charged leptons from different flavors of primary neutrino and their corresponding energy distributions. We find that the emergence probability of muons can be higher than that of taus for energies below 100 PeV, whether from a primary muon or $\tau$ neutrino, and that the Glashow resonance contributes to a surplus of emerging leptons near the resonant energy.

Establishing the axion as the dark matter (DM) particle after a haloscope discovery typically requires follow-up experiments to break the degeneracy between the axion’s coupling to photons and its local DM abundance. Given that a discovery would justify more significant investments, we explore the prospects of ambitious light-shining-through-a-wall (LSW) setups to probe the QCD axion band. Leveraging the excellent mass determination in haloscopes, we show how to design LSW experiments with lengths on the order of 100 km and suitably aligned magnetic fields with apertures of around 1 m to reach well-motivated axion models across up to four orders of magnitude in mass. Beyond presenting a concrete plan for postdiscovery experimental efforts, we briefly discuss complementary experiments and future directions beyond LSW experiments.

While the minimal anomaly-mediated SUSY breaking model (mAMSB) seems ruled out by constraints on Higgs mass, naturalness and wino dark matter, a slightly generalized version dubbed natural AMSB (nAMSB) remains both viable and compelling. Like mAMSB, nAMSB features winos as the lightest gauginos, but unlike mAMSB, nAMSB allows a small $\mu$ parameter so that Higgsinos are the lightest of electroweakinos (EWinos). nAMSB spectra depend on the input value of gravitino mass $m_{3/2}$, where the lower range of $m_{3/2}$ is excluded by LHC gluino pair searches while a higher $m_{3/2}$ band is excluded by LHC limits on wino pair production followed by boosted hadronic wino decays. A remaining intermediate gap in $m_{3/2}$ values remains allowed by present LHC searches, but appears to be completely explorable by high luminosity upgrades of LHC (HL-LHC). We explore a variety of compelling discovery channels that may allow one to close the intermediate gap in $m_{3/2}$ values: (1) same-sign $\mathrm{diboson}+{\cancel{E}}_T$ (SSdB) production arising from wino pair production, leading to same-sign dileptons plus missing $E_T$, (2) trilepton production arising from wino pair production and (3) soft dilepton plus jet events from Higgsino pair production, (4) top-squark pair production. From our signal-to-background analysis along a nAMSB model line, we expect HL-LHC to either discover or rule out the nAMSB model with $3000{\mathrm{fb}}^{-1}$ of integrated luminosity.

In this study, we calculate the mixing angles between the axial-vector mesons $D_{1(s1)}-D_{1(s1)}^{\prime }$ and $B_{1(s1)}-B_{1(s1)}^{\prime }$ using the QCD sum rules approach. Our results are ${\theta }_1=28.2\pm 0.6°$, ${\theta }_2=26.6\pm 0.6°$, ${\theta }_3=38.6\pm 0.1°$, and ${\theta }_4=38.5\pm 0.1°$. These values are in good agreement with the predictions of heavy quark effective theory, particularly for the mixing angle $\theta =35.3°$, and are compatible with several existing results in the literature. The predicted mixing angles can be tested through the analysis of semileptonic decays such as $B_c\to B_1\ell \nu$, $B_c\to B_{s1}^0\ell \nu$, $B_s\to D_{s1}\ell \nu$, and $B_s\to D_{s1}^{\prime }\ell \nu$, which can be investigated at experimental facilities such as LHCb and Belle II.

One-point correlators of conserved charges are argued to be perturbatively IR safe in quantum chromodynamics (QCD), which includes not only the density of energy, but also those of electric charge, isospin, and baryon number. Theoretical and phenomenological aspects of the density matrix of one-point correlators are discussed in the context of the states produced by a chiral current, as in the decay of a polarized electroweak boson. Densities of some nonconserved charges such as energy with arbitrary non-negative powers, despite their incalculability, are shown to obey an infinite set of consistency constraints. QCD is observed to live near a kink in the allowed parameter space of one-point correlators.

A back-to-back semi-inclusive $J/\psi +\text{jet}$ production is a promising process to study gluon transverse momentum distribution (TMD) at the future electron-ion collider. A back-to-back configuration allows a higher transverse momentum for $J/\psi$. We present an extension of a previous work where we studied $\cos 2\varphi$ azimuthal asymmetry within the TMD factorization framework for this process. We present and compare the effect of TMD evolution on the asymmetry, in two approaches that differ in the parametrization of the perturbative tails of the TMDs and the nonperturbative factors. We show that the asymmetry depends on the parametrizations of the nonperturbative Sudakov factors in the larger $b_T$ region and on the perturbative part of the evolution kernel. We use nonrelativistic QCD to estimate the $J/\psi$ production and show the effect of using different long-distance matrix element sets. Overall, the asymmetry after incorporating TMD evolution is small, but increases with the transverse momentum imbalance of the $J/\psi$-jet pair.

We explore a novel scenario involving Abelian–non-Abelian kinetic mixing within the framework of the Standard Model effective field theory (SMEFT) and its extension with a real triplet scalar field. In SMEFT, this mixing arises exclusively from a dimension-6 operator involving the Standard Model Higgs doublet, while the real triplet scalar field introduces an additional dimension-5 operator. We derive the modifications to electroweak gauge boson properties and impose constraints using electroweak precision data. In SMEFT, we find that $Z$-pole data at the Large Electron–Positron Collider imposes a stringent constraint on the kinetic mixing parameter, requiring it to be less than $\mathcal{O}({10}^{-4}$), which corresponds to a new physics scale of about 10 TeV. In the $\mathrm{SMEFT}+\mathrm{triplet}$ scenario, the constraint can be significantly relaxed with a sizeable triplet vacuum expectation value while preserving custodial symmetry in a finely tuned parameter space. Future measurements from the Circular Electron Positron Collider could probe the kinetic mixing parameter down to an order of magnitude smaller. Constraints from the Higgs signal strength data, $B_s\to {\mu }^{+}{\mu }^{-}$, and muon ($g-2$) are also discussed.

Using $(27.12\pm 0.14)\times {10}^8$ $\psi (2S)$ events collected by the BESIII detector operating at BEPCII, we search for the decay ${\eta }_c(2S)\to p\overline{p}$ via the process $\psi (2S)\to \gamma {\eta }_c(2S)$ and only find a signal with a significance of $1.7\sigma$. The upper limit of the product branching fraction at the 90% confidence level is determined to be $\mathcal{B}(\psi (2S)\to \gamma {\eta }_c(2S))\times \mathcal{B}({\eta }_c(2S)\to p\overline{p})<2.4\times {10}^{-7}$. The branching fractions of ${\chi }_{cJ}\to p\overline{p}(J=0,1,2)$ are also measured to be $\mathcal{B}({\chi }_{c0}\to p\overline{p})=(2.51\pm 0.02\pm 0.08)\times {10}^{-4}$, $\mathcal{B}({\chi }_{c1}\to p\overline{p})=(8.16\pm 0.09\pm 0.25)\times {10}^{-4}$, and $\mathcal{B}({\chi }_{c2}\to p\overline{p})=(8.33\pm 0.09\pm 0.22)\times {10}^{-4}$, where the first uncertainty is statistical and the second systematic.

A hybrid of the critical three-dimensional Gross-Neveu and Thirring models deformed by explicit parity-breaking operators is studied in the large-$N$ expansion and using the renormalization group. The regime of coupling constants where the theory is stable is identified and criteria for the occurrence of fixed points in that regime are found. For a certain range of Chern-Simons level, we find stable charge-gapped phase with spontaneously broken approximate scale invariance and a parametrically light dilaton. The Chern-Simons level can be tuned to the stability edge, resulting in exact scale invariance which is spontaneously broken, accompanied by a massless dilaton. For another, narrow range of Chern-Simons levels, we find a conformal window where the theory flows to a Wilson-Fisher-like fixed point and is a novel (and rare) example of a nonsupersymmetric nontrivial parity- and time-reversal-violating three-dimensional conformal field theory with scalar, spinor, and vector fields.

We discuss formation of cosmic strings associated with a spontaneously broken approximate $U(1)$ symmetry by performing classical field-theoretical simulations. An original $U(1)$ symmetry is explicitly broken down to its subgroup $Z_N$ even before spontaneous breaking takes place. We estimate the ratio of explicit breaking to that of spontaneous breaking for which topological defects for $N=1$ and $N=2$ are formed. For $N=1$, a cosmic string attached to a single domain wall can be formed when the amount of the explicit breaking is 3 orders of magnitude smaller than that of the spontaneous breaking. For $N=2$, no matter how large the explicit breaking is, domain walls are inevitably formed as long as the temperature of the Universe is high enough to restore $Z_2$ symmetry. In that case, cosmic strings are also inevitably formed as long as the amount of the explicit breaking is smaller than that of the spontaneous breaking.