Interactions between photons and electrons are ubiquitous in astrophysics. Photons can be downscattered (Compton scattering) or upscattered (inverse Compton scattering) by moving electrons. Inverse Compton scattering, in particular, is an essential process for the production of astrophysical gamma rays. Computations of inverse Compton emission typically adopts an isotropic or an ultrarelativistic assumption to simplify the calculation, which makes them unable to broadcast the formula to the whole phase space of source particles. In view of this, we develop a numerical scheme to compute the interactions between anisotropic photons and electrons without taking ultrarelativistic approximations. Compared to the ultrarelativistic limit, our exact results show major deviations when target photons are downscattered or when they possess energy comparable to source electrons. We also consider two test cases of high-energy inverse Compton emission to validate our results in the ultrarelativistic limit. In general, our formalism can be applied to cases of anisotropic electron-photon scattering in various energy regimes, and for computing the polarizations of the scattered photons.

This paper reports world averages of measurements of $b$-hadron, $c$-hadron, and $\tau$-lepton properties obtained by the Heavy Flavor Averaging Group using results available before April 2021. In rare cases, significant results obtained several months later are also used. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, $CP$ violation parameters, parameters of semileptonic decays, and Cabibbo-Kobayashi-Maskawa matrix elements.

We introduce the notion of “binary” positive and complex geometries, giving a completely rigid geometric realization of the combinatorics of generalized associahedra attached to any Dynkin diagram. We also define open and closed “cluster string integrals” associated with these “cluster configuration spaces”. The binary geometry of type $\mathcal{A}$ gives a gauge-invariant description of the usual open and closed string moduli spaces for tree scattering, making no explicit reference to a world sheet. The binary geometries and cluster string integrals for other Dynkin types provide a generalization of particle and string scattering amplitudes. Both the binary geometries and cluster string integrals enjoy remarkable factorization properties at finite ${\alpha }^{\prime }$, obtained simply by removing nodes of the Dynkin diagram. As ${\alpha }^{\prime }\to 0$ these cluster string integrals reduce to the canonical forms of the Arkani-Hamed-Bai-He-Yan (ABHY) generalized associahedron polytopes. For classical Dynkin types these are associated with $n$-particle scattering in the biadjoint ${\varphi }^3$ theory through one-loop order.

We introduce a bilinear form for Weyl scalar perturbations of Kerr. The form is symmetric and conserved, and we show that, when combined with a suitable renormalization prescription involving complex $r$ integration contours, quasinormal modes are orthogonal in the bilinear form for different $(l,m,n)$. These properties are apparently not evident consequences of standard properties for the radial and angular solutions to the decoupled Teukolsky relations and rely on the Petrov type D character of Kerr and its $t\text{−}\varphi$ reflection isometry. We show that quasinormal mode excitation coefficients are given precisely by the projection with respect to our bilinear form. These properties can make our bilinear form useful to set up a framework for nonlinear quasinormal mode coupling in Kerr. We also provide a general discussion on conserved local currents and their associated local symmetry operators for metric and Weyl perturbations, identifying a collection containing an increasing number of derivatives.

The novel data analysis challenges posed by the Laser Interferometer Space Antenna (LISA) arise from the overwhelmingly large number of astrophysical sources in the measurement band and the density with which they are found in the data. Robust detection and characterization of the numerous gravitational wave sources in LISA data can not be done sequentially, but rather through a simultaneous global fit of a data model containing the full suite of astrophysical and instrumental features present in the data. While previous analyses have focused on individual source types in isolation, here we present the first demonstration of a LISA global fit analysis containing combined astrophysical populations. The prototype pipeline uses a blocked Metropolis Hastings algorithm to alternatingly fit to a population of ultracompact galactic binaries, known “verification binaries” already identified by electromagnetic observations, a population of massive black hole mergers, and an instrument noise model. The global LISA analysis software suite (GLASS) is assembled from independently developed samplers for the different model components. The modular design enables flexibility to future development by defining standard interfaces for adding new, or updating additional, components to the global fit without being overly prescriptive for how those modules must be internally designed. The GLASS pipeline is demonstrated on data simulated for the LISA Data Challenge 2b. Results of the analysis and a road-map for continued development are described in detail.

Coleman–de Luccia transitions are spontaneous processes of nucleation of bubbles within metastable gravitational vacua including in their interior a true stable vacuum. From the perspective of lower-dimensional gauged supergravities obtained by truncating type II and M theory, these instantonic processes are represented by smooth domain walls featured by de Sitter foliations. These geometries must connect two different anti–de Sitter (AdS) vacua in such a way that the wall is defined by an interior and an exterior. We propose a first-order formulation for such radial flows and present two fully backreacted examples of gravitational instantons obtained through this technique, beyond the thin-wall approximation. In the first, we consider minimal 7D supergravity describing the truncation of M theory over a squashed four-sphere and admitting two ${\mathrm{AdS}}_7$ vacua, one supersymmetric and the other not. Second, we apply the same strategy to 6D Romans supergravity obtained with consistent truncation of massive IIA supergravity. Also in this case we derive a de Sitter domain wall interpolating between the Brandhuber-Oz vacuum and the nonsupersymmetric ${\mathrm{AdS}}_6$ vacuum of the theory.

We derive a new soft theorem that corresponds to the spontaneous breaking of Lorentz boosts. This is motivated by the dynamics of inflation in the subhorizon (flat-space) limit, where spacetime becomes flat but Lorentz boosts are still broken. In this limit, the scattering amplitudes become sensible observables. We relate the soft emission of a Goldstone boson to the (nonrelativistic) Lorentz boost of the hard scattering amplitudes. This is the on-shell avatar of the spontaneous breaking of Lorentz boosts, analogous to the Adler zero of pions in the chiral symmetry breaking. We comment on several applications to inflation, including the demonstration that Dirac-Born-Infeld inflation is the unique theory that has an emergent Lorentz invariance when the boosts are spontaneously broken.

We report on the first observation of the diffuse cosmic neutrino flux with the Baikal-GVD neutrino telescope. Using cascadelike events collected by Baikal-GVD in 2018–2021, a significant excess of events over the expected atmospheric background is observed. This excess is consistent with the high-energy diffuse cosmic neutrino flux observed by IceCube. The null cosmic flux assumption is rejected with a significance of $3.05\sigma$. Assuming a single power law model of the astrophysical neutrino flux with identical contribution from each neutrino flavor, the following best-fit parameter values are found: the spectral index ${\gamma }_{\text{astro}}={2.58}_{-0.33}^{+0.27}$ and the flux normalization ${\varphi }_{\text{astro}}={3.04}_{-1.21}^{+1.52}$ per one flavor at 100 TeV.

We study the dynamics of $U(1)$ gauged $Q$-balls using fully nonlinear numerical evolutions in axisymmetry. Focusing on two models with logarithmic and polynomial scalar field potentials, we numerically evolve perturbed gauged $Q$-ball configurations in order to assess their stability and determine the fate of unstable configurations. Our simulations suggest that there exist both stable and unstable branches of solutions with respect to axisymmetric perturbations. For solutions belonging to the stable branch, the gauged $Q$-balls respond to the perturbations by oscillating continuously or weakly radiating before returning to the initial configuration. For the unstable branch, the solutions are eventually destroyed and can evolve in several ways, such as dispersal of the fields to infinity or fragmentation into smaller gauged $Q$-balls. In some cases, we observe the formation of ringlike structures which we call “gauged $Q$-rings.” We also investigate the stability of gauged $Q$-balls when the gauge coupling is small, finding that the behavior of these configurations closely resembles that of ordinary (nongauged) $Q$-balls.

We develop an exact formalism for the computation of the abundance of primordial black holes (PBHs) in the presence of local non-Gaussianity (NG) in the curvature perturbation field. For the first time, we include NG going beyond the widely used quadratic and cubic approximations, and consider a completely generic functional form. Adopting threshold statistics on the compaction function, we address the computation of the abundance both for narrow and broad power spectra. While our formulas are generic, we discuss explicit examples of phenomenological relevance considering the physics case of the curvaton field. We carefully assess under which conditions the conventional perturbative approach can be trusted. In the case of a narrow power spectrum, this happens only if the perturbative expansion is pushed beyond the quadratic order (with the optimal order of truncation that depends on the width of the spectrum). Most importantly, we demonstrate that the perturbative approach is intrinsically flawed when considering broad spectra, in which case only the nonperturbative computation captures the correct result. Finally, we describe the phenomenological relevance of our results for the connection between the abundance of PBHs and the stochastic gravitational wave (GW) background related to their formation. As NGs modify the amplitude of perturbations necessary to produce a given PBH abundance and boost PBH production at large scales for broad spectra, modeling these effects is crucial to connect the PBH scenario to its signatures at current and future GW experiments.

Gravitational waves (GWs) create correlations in the arrival times of pulses from different pulsars. The expected correlation $\mu (\gamma )$ as a function of the angle $\gamma$ between the directions to two pulsars was calculated by Hellings and Downs for an isotropic and unpolarized GW background, and several pulsar timing array (PTA) collaborations are working to observe these. We ask: given a set of noise-free observations, are they consistent with that expectation? To answer this, we calculate the expected variance ${\sigma }^2(\gamma )$ in the correlation for a single GW point source, as pulsar pairs with fixed separation angle $\gamma$ are swept around the sky. We then use this to derive simple analytic expressions for the variance produced by a set of discrete point sources uniformly scattered in space for two cases of interest: (1) point sources radiating GWs at the same frequency, generating confusion noise, and (2) point sources radiating GWs at distinct nonoverlapping frequencies. By averaging over all pulsar sky positions at fixed separation angle $\gamma$, we show how this variance may be cleanly split into cosmic variance and pulsar variance, also demonstrating that measurements of the variance can provide information about the nature of GW sources. In a series of technical appendices, we calculate the mean and variance of the Hellings-Downs correlation for an arbitrary (polarized) point source, quantify the impact of neglecting pulsar terms, and calculate the pulsar and cosmic variance for a Gaussian ensemble. The mean and variance of the Gaussian ensemble may be obtained from the previous discrete-source confusion-noise model in the limit of a high density of weak sources.

Many binary systems of interest for gravitational-wave astronomy are orbited by a third distant body, which can considerably alter their relativistic dynamics. Precision computations are needed to understand the interplay between relativistic corrections and three-body interactions. We use an effective field theory approach to derive the effective action describing the long-timescale dynamics of hierarchical three-body systems up to 1PN quadrupole order. At this level of approximation, computations are complicated by the backreaction of small oscillations on orbital timescales as well as deviations from the adiabatic approximation. We address these difficulties by eliminating the fast modes through the method of near-identity transformations. This allows us to compute for the first time the complete expression of the 1PN quadrupole cross terms in generic configurations of three-body systems. We numerically integrate the resulting equations of motion and show that 1PN quadrupole terms can affect the long term dynamics of relativistic three-body systems.

We study probes of neutral triple gauge couplings (nTGCs) at the LHC and the proposed 100 TeV $pp$ colliders, and compare their sensitivity reaches with those of proposed $e^{+}{e}^{-}$ colliders. The nTGCs provide a unique window to the new physics beyond the Standard Model (SM) because they can arise from SM effective field theory operators that respect the full electroweak gauge group $\mathrm{SU}(2{)}_{\mathrm{L}}\otimes {\mathrm{U}(1)}_{\mathrm{Y}}$ of the SM only at the level of dimension-8 or higher. We derive the neutral triple gauge vertices (nTGVs) generated by these dimension-8 operators in the broken phase and map them onto a newly generalized form factor formulation, which takes into account only the residual $\mathrm{U}(1{)}_{\mathrm{em}}$ gauge symmetry. Using this mapping, we derive new nontrivial relations between the form factors that guarantee a truly consistent form factor formulation of the nTGVs and remove large unphysical energy-dependent terms. We then analyze the sensitivity reaches of the LHC and future 100 TeV hadron colliders for probing the nTGCs via both the dimension-8 nTGC operators and the corresponding nTGC form factors in the reaction $pp(q\overline{q})\to Z\gamma$ with $Z\to {\ell }^{+}{\ell }^{-}$, $\nu \overline{\nu }$. We compare their sensitivities with the existing LHC measurements of nTGCs and with those of the high-energy $e^{+}{e}^{-}$ colliders. In general, we find that the prospective LHC sensitivities are comparable to those of an $e^{+}{e}^{-}$ collider with center-of-mass energy $\le 1\mathrm{TeV}$, whereas an $e^{+}{e}^{-}$ collider with center-of-mass energy (3–5) TeV would have greater sensitivities, and a 100 TeV $pp$ collider could provide the most sensitive probes of the nTGCs.

Gravitational-wave (GW) detectors that monitor fluctuations in the separation between inertial test masses (TMs) are sensitive to new forces acting on those TMs. Ultralight dark-photon dark matter (DPDM) coupled to $U(1{)}_B$ or $U(1{)}_{B-L}$ charges supplies one such force that oscillates with a frequency set by the DPDM mass. GW detectors operating in different frequency bands are thus sensitive to different DPDM mass ranges. A recent GW detection proposal based on monitoring the separation of certain asteroids in the inner Solar System would have sensitivity to $\mathrm{\mu }\mathrm{Hz}$ frequencies [M. A. Fedderke et al., Asteroids for $\mathrm{\mu }\mathrm{Hz}$ gravitational-wave detection, Phys. Rev. D 105, 103018 (2022)]. In this paper, we show how that proposal would also enable access to new parameter space for DPDM coupled to $B$ [respectively, $B-L$] charges in the mass range $5[9]\times {10}^{-21}\mathrm{eV}\lesssim m_{\mathrm{DM}}\lesssim 2\times {10}^{-19}\mathrm{eV}$, with peak sensitivities about a factor of 500 [50] beyond current best limits on ${ϵ}_B$ [${ϵ}_{B-L}$] at $m_{\mathrm{DM}}\sim 2\times {10}^{-19}\mathrm{eV}$. Sensitivity could be extended up to $m_{\mathrm{DM}}\sim 2\times {10}^{-18}\mathrm{eV}$ only if noise issues associated with asteroid rotational motion could be overcome.

Following inflation, the Universe may pass through an early matter-dominated phase supported by the oscillating inflaton condensate. Initially small fluctuations in the condensate grow gravitationally on subhorizon scales and can collapse to form nonlinear “inflaton halos.” Their formation and subsequent tidal interactions will source gravitational waves, resulting in a stochastic background in the present Universe. We extend N-body simulations that model the growth and interaction of collapsed structures to compute the resulting gravitational wave emission. The spectrum of this radiation is well matched by semianalytical estimates based on the collapse of inflaton halos and their tidal evolution. We use this semianalytic formalism to infer the spectrum for scenarios where the early matter-dominated phase gives way to a thermalized universe at temperatures as low as 100 MeV and we discuss the possible experimental opportunities created by this signal in inflationary models in which thermalization takes place long after inflation has completed.

We present cosmological constraints from the analysis of two-point correlation functions between galaxy positions and galaxy lensing measured in Dark Energy Survey (DES) Year 3 data and measurements of cosmic microwave background (CMB) lensing from the South Pole Telescope (SPT) and Planck. When jointly analyzing the DES-only two-point functions and the DES cross-correlations with $\mathrm{SPT}+Planck$ CMB lensing, we find ${\mathrm{\Omega }}_{\mathrm{m}}=0.344\pm 0.030$ and $S_8\equiv {\sigma }_8({\mathrm{\Omega }}_{\mathrm{m}}/0.3{)}^{0.5}=0.773\pm 0.016$, assuming $\mathrm{\Lambda }\mathrm{CDM}$. When additionally combining with measurements of the CMB lensing autospectrum, we find ${\mathrm{\Omega }}_{\mathrm{m}}={0.306}_{-0.021}^{+0.018}$ and $S_8=0.792\pm 0.012$. The high signal-to-noise of the CMB lensing cross-correlations enables several powerful consistency tests of these results, including comparisons with constraints derived from cross-correlations only, and comparisons designed to test the robustness of the galaxy lensing and clustering measurements from DES. Applying these tests to our measurements, we find no evidence of significant biases in the baseline cosmological constraints from the DES-only analyses or from the joint analyses with CMB lensing cross-correlations. However, the CMB lensing cross-correlations suggest possible problems with the correlation function measurements using alternative lens galaxy samples, in particular the redmagic galaxies and high-redshift maglim galaxies, consistent with the findings of previous studies. We use the CMB lensing cross-correlations to identify directions for further investigating these problems.

Cross-correlations of galaxy positions and galaxy shears with maps of gravitational lensing of the cosmic microwave background (CMB) are sensitive to the distribution of large-scale structure in the Universe. Such cross-correlations are also expected to be immune to some of the systematic effects that complicate correlation measurements internal to galaxy surveys. We present measurements and modeling of the cross-correlations between galaxy positions and galaxy lensing measured in the first three years of data from the Dark Energy Survey with CMB lensing maps derived from a combination of data from the $2500{\mathrm{deg}}^2$ SPT-SZ survey conducted with the South Pole Telescope and full-sky data from the Planck satellite. The CMB lensing maps used in this analysis have been constructed in a way that minimizes biases from the thermal Sunyaev Zel’dovich effect, making them well suited for cross-correlation studies. The total signal-to-noise of the cross-correlation measurements is 23.9 (25.7) when using a choice of angular scales optimized for a linear (nonlinear) galaxy bias model. We use the cross-correlation measurements to obtain constraints on cosmological parameters. For our fiducial galaxy sample, which consist of four bins of magnitude-selected galaxies, we find constraints of ${\mathrm{\Omega }}_{\mathrm{m}}={0.272}_{-0.052}^{+0.032}$ and $S_8\equiv {\sigma }_8\sqrt{{\mathrm{\Omega }}_{\mathrm{m}}/0.3}={0.736}_{-0.028}^{+0.032}$ (${\mathrm{\Omega }}_{\mathrm{m}}={0.245}_{-0.044}^{+0.026}$ and $S_8={0.734}_{-0.028}^{+0.035}$) when assuming linear (nonlinear) galaxy bias in our modeling. Considering only the cross-correlation of galaxy shear with CMB lensing, we find ${\mathrm{\Omega }}_{\mathrm{m}}={0.270}_{-0.061}^{+0.043}$ and $S_8={0.740}_{-0.029}^{+0.034}$. Our constraints on $S_8$ are consistent with recent cosmic shear measurements, but lower than the values preferred by primary CMB measurements from Planck.

Joint analyses of cross-correlations between measurements of galaxy positions, galaxy lensing, and lensing of the cosmic microwave background (CMB) offer powerful constraints on the large-scale structure of the Universe. In a forthcoming analysis, we will present cosmological constraints from the analysis of such cross-correlations measured using Year 3 data from the Dark Energy Survey (DES), and CMB data from the South Pole Telescope (SPT) and Planck. Here we present two key ingredients of this analysis: (1) an improved CMB lensing map in the SPT-SZ survey footprint and (2) the analysis methodology that will be used to extract cosmological information from the cross-correlation measurements. Relative to previous lensing maps made from the same CMB observations, we have implemented techniques to remove contamination from the thermal Sunyaev Zel’dovich effect, enabling the extraction of cosmological information from smaller angular scales of the cross-correlation measurements than in previous analyses with DES Year 1 data. We describe our model for the cross-correlations between these maps and DES data, and validate our modeling choices to demonstrate the robustness of our analysis. We then forecast the expected cosmological constraints from the galaxy survey-CMB lensing auto and cross-correlations. We find that the galaxy-CMB lensing and galaxy shear-CMB lensing correlations will on their own provide a constraint on $S_8={\sigma }_8\sqrt{{\mathrm{\Omega }}_{\mathrm{m}}/0.3}$ at the few percent level, providing a powerful consistency check for the DES-only constraints. We explore scenarios where external priors on shear calibration are removed, finding that the joint analysis of CMB lensing cross-correlations can provide constraints on the shear calibration amplitude at the 5% to 10% level.

Accurate numerical-relativity simulations are essential to study the rich phenomenology of binary neutron star systems. In this work, we focus on the material that is dynamically ejected during the merger process and on the kilonova transient it produces. Typically, radiative transfer simulations of kilonova light curves from ejecta make the assumption of homologous expansion, but this condition might not always be met at the end of usually very short numerical-relativity simulations. In this article, we adjust the infrastructure of the bam code to enable longer simulations of the dynamical ejecta with the aim of investigating when the condition of homologous expansion is satisfied. In fact, we observe that the deviations from a perfect homologous expansion are about $\lesssim 30\%$ at roughly 100 ms after the merger. While the calculation of the kilonova light curves is affected by the resolution as well as our method of simplifying the ejecta simulation, these deviations from the homologous expansion also bias the results. We determine this influence by extracting the ejecta data for different reference times and use them as input to radiative transfer simulations. Our results show that the light curves for extraction times later than 80 ms after the merger deviate by $\lesssim 0.4\mathrm{mag}$ and are mostly consistent with numerical noise. Accordingly, deviations from the homologous expansion for the dynamical ejecta component are negligible from $\sim 80\mathrm{ms}$ for the purpose of kilonova modeling.

Using recent results in four-derivative 5d $\mathcal{N}=2$ minimal gauged supergravity, we evaluate the regularized on-shell action of the Euclidean solution in this theory that admits a Lorentzian continuation to an ${\mathrm{AdS}}_5$ black hole with one electric charge and two angular momenta. We focus on the supersymmetric limit of this solution and employ holography to show that the result can be expressed purely in terms of angular momentum fugacities and the ’t Hooft anomalies for the $\mathrm{U}(1{)}_{\mathrm{R}}$ R symmetry of the dual 4d $\mathcal{N}=1$ superconformal field theory. This holographic calculation is in perfect agreement with recent studies of the 4d $\mathcal{N}=1$ superconformal index “on the second sheet.” We illustrate the utility of these results in two classes of 4d $\mathcal{N}=1$ holographic SCFTs that have ’t Hooft anomalies with suitable large-$N$ behavior that leads to nontrivial corrections at first subleading order in the $1/N$ expansion. We also explicitly calculate the Wald entropy of the black hole solution and delineate the leading four-derivative corrections to the Bekenstein-Hawking entropy.