Extreme mass-ratio inspirals are among the key sources of gravitational waves for the Laser Interferometer Space Antenna space-based gravitational-wave detector. Achieving sufficient accuracy in the gravitational-wave template for these binaries requires modeling the effects of the spin of the comparably light secondary compact object. In this work, we employ the solution of the Hamilton-Jacobi equations for the motion of spinning bodies in Kerr space-time for the first time to obtain general bound orbits. Specifically, we implement a new solver for the Mathisson-Papapetrou-Dixon equations of motion reduced to first-order form. Our approach provide novel semianalytical expressions for the spin corrections to the orbital motion and frequencies, valid for any choice of referential geodesics, and new analytic expressions for the constants of motion shifts. Then, using the Teukolsky formalism, we compute gravitational-wave energy and angular-momentum fluxes sourced by these orbits valid to linear order in secondary spin and provide waveform snapshots corresponding to the motion. The solver and the novel method we have developed substantially improve on previous studies in terms of speed and accuracy. Additionally, we include the full effect of a general precessing secondary spin in the waveform for the first time. As such, it provides a breakthrough building block for the modeling of waveforms of precessing compact binaries at large mass ratios.

Gravitational waves (GWs) from gravitational three-body decay (graviton bremsstrahlung process) can leave an indelible signal at ultrahigh frequencies. We focus on a scenario where superheavy particles are produced gravitationally at a transition between the inflationary and kination phases and analyze the detectability of the signal in the presence of GWs generated from the vacuum fluctuations during inflation. We find that, in many cases, GWs from the graviton bremsstrahlung are buried in the stochastic gravitational wave background originating from inflation. However, if the superheavy particles are as heavy as the Planck scale, the graviton bremsstrahlung can produce a sizable amount of GWs, surpassing the inflationary ones.

The peculiar motion of massive objects across the line of sight imprints a dipolar temperature anisotropy pattern on the cosmic microwave background known as the moving lens effect. This effect provides a unique probe of the transverse components of the peculiar velocity field, but has not yet been detected due to its small size. We implement and validate a stacking estimator for the moving lens signal using a galaxy catalog as a tracer of massive haloes combined with reconstructed velocities from the galaxy number density field. Using simulations, we forecast detection prospects for the moving lens signal from current and upcoming microwave background and galaxy surveys. We demonstrate a new foreground mitigation strategy likely sufficient for current datasets, and discuss various sources of systematic error and noise. Upcoming galaxy surveys will provide high-significance statistical detections of the moving lens effect.

If ultralight boson fields exist, then vacuum misalignment populates them with nonzero relic abundance. For a broad range of particle mass $m$ the field condenses into fuzzy cores in massive galaxies. We use numerical simulations to test this idea, extending previous work [Blum and Teodori, Phys. Rev. D 104, 123011 (2021)] and focusing on ultralight dark matter (ULDM) that makes up a subdominant fraction of the total dark matter density, consistent with observational constraints. Our simulations mimic galactic halos and explore different initial conditions and levels of sophistication in the modeling of the halo potential. For $m\sim {10}^{-25}\mathrm{eV}$ ULDM cores act as approximate internal mass sheets in strong gravitational lensing, and could first be detected using time delays in cosmography, when an $H_0$ prior is assumed: a scenario we dub AxionH0graphy. The mass sheet degeneracy is broken by finite core radius and by the dynamical displacement of cores from the halo center of mass, which introduce imaging distortions and restrict the $H_0$ signal limit of AxionH0graphy to $m\lesssim 5\times {10}^{-25}\mathrm{eV}$. Cosmological simulations are called for to sharpen the predicted connection between the amplitude of ULDM galactic cores and the ULDM cosmological fraction.

Recent pulsar timing array (PTA) experiments have reported strong evidence of the stochastic gravitational wave background (SGWB). If interpreted as primordial gravitational waves, the signal favors a strongly blue-tilted spectrum. On the other hand, the Ekpyrosis-bouncing cosmology with a strongly blue-tilted gravitational wave spectrum, i.e., $n_T\simeq 2$, offers a potential explanation for the observed SGWB signal. In this paper, we construct a concrete Ekpyrosis-bouncing model, and show its capacity to intepret the PTA result without pathologies. Both tensor and scalar perturbations are analyzed with constraints from the current observations.

In direct searches of dark matter, multiscatter signatures are now being sought to probe scattering cross sections that are large enough to make the detector optically thick to incident particles. We provide some significant updates to the multiscatter program. Using considerations of energy deposition, we derive the reaches in cross section and mass of various proposed large-volume detectors: a kilotonne fiducial mass “module of opportunity” at DUNE, a kilotonne xenon detector suggested for neutrinoless double beta decay, the gaseous detector CYGNUS, and the dark matter detectors XLZD and Argo. Where the velocity vector can be reconstructed event-by-event, the Galactic dark matter velocity distribution may be inferred. We exploit this to show that halo substructure such as tidal streams can be picked up if they make up about 10% of the local dark matter density.

Continuous gravitational waves (CGWs) from various astrophysical sources are one of the many future probes of upcoming gravitational wave (GW) search missions. Neutron stars (NSs) with deformity are one of the leading sources of CGW emissions. In this work, for the first time, a novel attempt to estimate the dark matter (DM) capture rate is performed using CGW as the probe to the local NS population. Competitive bounds on DM capture from the local NS population are reported when compared with DM direct search experiments and other astrophysical observations.

We investigate radial oscillations of protoneutron stars (PNSs), employing equations of state described by the Brueckner-Hartree-Fock theory or the relativistic mean field model, and assuming isentropy and fixed lepton fractions for the internal structure. We calculate the eigenfrequencies and corresponding oscillation functions, which show different characteristics in different mass regions. In the low-mass region around $1.4M_{\odot }$, the radial oscillation frequencies are lowered by large entropy and neutrino trapping, along with a reduction of the average adiabatic index. Therefore, during the PNS evolution to a cold neutron star, the frequency increases substantially. In the region close to the maximum mass, the fundamental oscillation frequency drops rapidly and vanishes at the maximum mass, in accordance with the critical stability criterion $\partial M/\partial {\rho }_c=0$, as for cold neutron stars.

Charged leptons produced by high-energy and ultrahigh-energy neutrinos have a substantial probability of emitting prompt internal bremsstrahlung ${\nu }_{\ell }+N\to \ell +X+\gamma$. This can have important consequences for neutrino detection. We discuss observable consequences at high- and ultrahigh-energy neutrino telescopes and the Large Hadron Collider’s (LHC’s) Forward Physics Facility. Logarithmic enhancements can be substantial (e.g., $\sim 20\%$) when either the charged lepton’s energy or the rest of the cascade is measured. We comment on final state radiation’s impacts on measuring the inelasticity distribution, $\nu /\overline{\nu }$ flux ratio, throughgoing muons, and double-bang signatures for high-energy neutrino observation. Furthermore, for ultrahigh-energy neutrino observation, we find that final state radiation increases the overall detectable energy by as much as 20%, affects flavor measurements, and decreases the energy of both Earth-emergent tau leptons and regenerated tau neutrinos. Many of these have significant impacts on measuring neutrino fluxes and spectra. Finally, for the LHC’s Forward Physics Facility, we find that final state radiation will impact future extractions of strange quark parton distribution functions. Final state radiation should be included in future analyses at neutrino telescopes and the Forward Physics Facility.

We probe the intrinsic differences in simulated gravitational-wave signals from binary neutron star (BNS) mergers, arising from varying approaches to incorporating thermal effects in numerical-relativity modeling. We consider a hybrid approach in which the equation of state (EOS) comprises a cold, zero-temperature, piecewise-polytropic part and a thermal part described by an ideal gas and a tabulated approach based on self-consistent, microphysical, finite-temperature EOS. We use time-domain waveforms corresponding to BNS merger simulations with four different EOSs. Those are injected into Gaussian noise given by the sensitivity of the third-generation detector Einstein Telescope and reconstructed using BayesWave, a Bayesian data-analysis algorithm that recovers the signals through a model-agnostic approach. The two representations of thermal effects result in different dominant peak frequencies in the spectra of the postmerger signals, for both the quadrupole fundamental mode and the late-time inertial modes. For some of the EOSs investigated, those differences are large enough to be told apart, especially in the early postmerger phase when the signal amplitude is the loudest. Our results suggest that a self-consistent treatment of thermal effects in BNS postmerger modeling is essential to prevent significant parameter biases in upcoming gravitational-wave detections.

Fermi balls are nontopological solitons that can naturally form in an early Universe containing a dark sector with heavy fermions and an attractive interaction mediated by a light scalar field. We compute the Fermi ball mass and radius scaling relations when the potential of the scalar field $\phi$ has a non-negligible quartic coupling $\lambda {\phi }^4$. The resulting Fermi balls reach “saturation” very rapidly, even when their radius is much smaller than the effective Yukawa force range. These objects can therefore grow by mergers or by the accretion of ambient dark fermions until they become so dense that they fall within their Schwarzschild radius and collapse to black holes. This setup, therefore, provides an example of a rather natural and economical dark sector scenario for the formation of primordial black holes.

We develop a general framework for calculating the leading-order, general relativistic contributions to the gravitational phase shift in single-photon atom interferometers within the context of linearized gravity. We show that the atom gradiometer observable, which only depends on the atom interferometer propagation phase, can be written in terms of three distinct contributions: the Doppler phase shift, which accounts for the tidal displacement of atoms along the baseline, the Shapiro phase shift, which accounts for the delay in the arrival time of photons at atom-light interaction points, and the Einstein phase shift, which accounts for the gravitational redshift measured by the atoms. For specific atom gradiometer configurations, we derive the signal and response functions for two physically motivated scenarios: (i) transient gravitational waves in the transverse-traceless gauge and, for the first time, in the proper detector frame, and (ii) transient massive objects sourcing weak and slow-varying Newtonian potentials. We find that the Doppler contribution of realistic Newtonian noise sources (e.g., a freight truck or a piece of space debris) at proposed atom gradiometer experiments, such as AION, MAGIS, and AEDGE, can exceed the shot noise level and thus affect physics searches if not properly subtracted.

In this article, we present results on the simulated performance of an instrumented baffle installed at the entrance of the vacuum towers hosting the end mirrors of Virgo’s main Fabry-Pérot cavities. The installation of instrumented baffles is part of the Advanced Virgo Plus upgrade in time for the O5 observing run. They were originally envisaged to be suspended, mounted on new payloads and surrounding new larger end mirrors. The current Virgo upgrade plan includes the replacement of the mirrors with new ones of better quality and same dimensions, leaving the installation of new payloads and larger end mirrors to a post-O5 upgrade phase still to be defined. Here we demonstrate that placing the instrumented baffles just beyond the cryotrap gate valve and in front of the end mirrors would be equally effective for monitoring scattered light inside the cavities. This new location, more than a meter away from the mirror, further reduces the risk of contamination and any potential interference with the mirrors, preserves the full capability to monitor scattered light, and decouples the instrumented baffle timeline from the plans for installing large mirrors in the experiment. We provide an estimate of the light distribution the baffles would encounter under both nominal and non-nominal conditions, as well as an assessment of the scattered light noise introduced by these baffles in this new location, confirming that they would not compromise Virgo’s sensitivity.

We study the decay processes of $B\to \rho \eta$, $\rho {\eta }^{\prime }$ in the perturbative quantum chromodynamics (QCD) approach with a few improvements incorporated in it, where the contributions with large momentum transfer are calculated perturbatively, and the contributions with lower energy scale are treated by introducing soft transition form factors. In addition, color-octet contributions are introduced which are essentially long-distance contributions. With reasonable input parameters selected, we find that the theoretical results of the branching ratios and $CP$ violations are all consistent with experimental data. We also predict some unmeasured quantities, which can be tested by experiment in the future.

General consistency requirements of quantum gravity suggest the existence of one axion per Yang-Mills group (YM) [a gauged special unitary group SU(n)]. In this work we take this requirement seriously and consider theories with dark Yang-Mills sectors and investigate general phenomenological implications of these axions. We carry out computations for two simple models, namely a pure Yang-Mills sector and $N$ exact Standard Model (SM) copies. For the former, the misalignment mechanism results in a minimal dark confinement scale ${\mathrm{\Lambda }}_{\mathrm{conf}}\gtrsim 1\mathrm{eV}$ if the dark sector axion is supposed to make up the dark matter. For the latter, the misalignment mechanism without fine-tuning of the initial misalignment angle places an upper bound on $N$ below the species bound. When the Peccei-Quinn symmetries are broken during inflation, the collective isocurvature fluctuations do not necessarily tighten the bound on the inflationary Hubble scale arising from a single axion. We also point out that axion stars collectively made from axions of different dark sectors with a suppressed mass spectrum are not possible. Lastly, for the two models at hand, intersector interaction through axion kinetic mixing leads to the existence of two distinct axion states. For a single dark YM sector, the upper bound ${\mathrm{\Lambda }}_{\mathrm{conf}}\lesssim {10}^{12}\mathrm{GeV}$ emerges from the stability requirement of the dark sector axion. For $N$ exact SM copies, the mass and photon coupling of the second state is completely determined after a potential measurement of the analogous parameters of the first axion.

In this work, we develop a numerical technique for the optimal estimation of the new physics (NP) couplings applicable to any collider process without any simplifying assumptions. This approach also provides a way to measure the quality of the NP estimates derived using standard ${\chi }^2$ analysis, and can be used to gauge the advantages of various modalities of collider design. We illustrate the techniques and arguments by considering the pair production of heavy charged fermions at an $e^{+}{e}^{-}$ collider.

We propose an extension of the minimal scotogenic model with a triplet fermion and a singlet scalar. An imposed $Z_4\times Z_2$ symmetry allows only diagonal Yukawa couplings among different generations of standard model (SM) leptons and right-handed singlet neutrinos. The Yukawa coupling of the triplet fermion with the inert doublet positively contributes to the muon anomalous magnetic moment. The imposed $Z_4\times Z_2$ symmetry forbids the conventional leptogenesis from the lightest right-handed neutrino decay. A net lepton asymmetry can be generated in the muonic sector from $N_2$ and triplet fermion decay through resonant leptogenesis scenario. The Yukawa coupling of triplet plays significant role both in leptogenesis and in the anomalous magnetic moment of the muon. We show a viable parameter space for TeV scale leptogenesis while explaining the Fermilab results. The inert scalar is the dark matter candidate in this model. The muon ($g-2$) and dark matter both favor the same parameter space for mass of the dark matter and the triplet fermion.

We present analytic expressions for three-flavor neutrino oscillations in presence of invisible neutrino decay and matter effects. Using the well-known Cayley-Hamilton formalism, the leading-order terms are derived for oscillation probabilities in all major channels assuming the neutrino mass eigenstate ${\nu }_3$ to decay. Our work extends and complements previous studies utilizing the Cayley-Hamilton theorem, providing the series expansions for ${\nu }_e\to {\nu }_e$, ${\nu }_e\to {\nu }_{\mu }$, ${\nu }_e\to {\nu }_{\tau }$, ${\nu }_{\mu }\to {\nu }_{\mu }$, and ${\nu }_{\mu }\to {\nu }_{\tau }$. The accuracy of the analytical formulas is investigated by comparing the results with numerically calculated probabilities. We also comment on the implications on unitarity violation.

We introduce an approach for approximate real-time evolution of quantum systems using tensor renormalization group (TRG) methods originally developed for imaginary time. We use higher-order TRG to generate a coarse-grained time evolution operator for a $1+1\mathrm{D}$ transverse Ising model with a longitudinal field. We show that the standard tensor norm used for the singular value decomposition-based truncation is degenerate and propose an alternate method to discriminate. We show that it is effective and efficient in evolving Gaussian wave packets for one and two particles in the disordered phase, while ordered phase behavior is more challenging to capture. We compare our algorithm with local simulators for universal quantum computers and discuss possible benchmarking in the near future.

We study the impact of Gribov copies on the quark propagator in lattice 2-color quantum chromodynamics (QCD). We find that the Gribov noise is comparable to the gauge noise for smaller volumes but becomes less significant for larger spatial volumes. The Gribov noise in the quark propagator is found to be comparable to, but smaller than in the gluon propagator on the same ensembles. No correlation is found between the values of either of the quark propagator form factors and the value of the gauge fixing functional, nor between the two form factors.