We constrain six possible extensions to the $\mathrm{\Lambda }$ cold dark matter (CDM) model using measurements from the Dark Energy Survey’s first three years of observations, alone and in combination with external cosmological probes. The DES data are the two-point correlation functions of weak gravitational lensing, galaxy clustering, and their cross-correlation. We use simulated data vectors and blind analyses of real data to validate the robustness of our results to astrophysical and modeling systematic errors. In many cases, constraining power is limited by the absence of theoretical predictions beyond the linear regime that are reliable at our required precision. The $\mathrm{\Lambda }\mathrm{CDM}$ extensions are dark energy with a time-dependent equation of state, nonzero spatial curvature, additional relativistic degrees of freedom, sterile neutrinos with eV-scale mass, modifications of gravitational physics, and a binned ${\sigma }_8(z)$ model which serves as a phenomenological probe of structure growth. For the time-varying dark energy equation of state evaluated at the pivot redshift we find $(w_{\mathrm{p}},w_a)=(-0.99_{-0.17}^{+0.28},-0.9\pm 1.2)$ at 68% confidence with $z_{\mathrm{p}}=0.24$ from the DES measurements alone, and $(w_{\mathrm{p}},w_a)=(-1.03_{-0.03}^{+0.04},-0.4_{-0.3}^{+0.4})$ with $z_{\mathrm{p}}=0.21$ for the combination of all data considered. Curvature constraints of ${\mathrm{\Omega }}_k=0.0009\pm 0.0017$ and effective relativistic species $N_{\mathrm{eff}}=3.10_{-0.16}^{+0.15}$ are dominated by external data, though adding DES information to external low-redshift probes tightens the ${\mathrm{\Omega }}_k$ constraints that can be made without cosmic microwave background observables by 20%. For massive sterile neutrinos, DES combined with external data improves the upper bound on the mass $m_{\mathrm{eff}}$ by a factor of 3 compared to previous analyses, giving 95% limits of $(\mathrm{\Delta }{N}_{\mathrm{eff}},m_{\mathrm{eff}})\le (0.28,0.20\mathrm{eV})$ when using priors matching a comparable Planck analysis. For modified gravity, we constrain changes to the lensing and Poisson equations controlled by functions $\mathrm{\Sigma }(k,z)={\mathrm{\Sigma }}_0{\mathrm{\Omega }}_{\mathrm{\Lambda }}(z)/{\mathrm{\Omega }}_{\mathrm{\Lambda },0}$ and $\mu (k,z)={\mu }_0{\mathrm{\Omega }}_{\mathrm{\Lambda }}(z)/{\mathrm{\Omega }}_{\mathrm{\Lambda },0}$, respectively, to ${\mathrm{\Sigma }}_0=0.6_{-0.5}^{+0.4}$ from DES alone and $({\mathrm{\Sigma }}_0,{\mu }_0)=(0.04\pm 0.05,0.08_{-0.19}^{+0.21})$ for the combination of all data, both at 68% confidence. Overall, we find no significant evidence for physics beyond $\mathrm{\Lambda }\mathrm{CDM}$.

We test the hypothesis of starburst galaxies as sources of ultrahigh energy cosmic rays and high energy neutrinos. The computation of interactions of ultrahigh energy cosmic rays in the starburst environment as well as in the propagation to Earth is made using a modified version of the Monte Carlo code SimProp, where hadronic processes in the environment of sources are implemented for the first time. Taking into account a star-formation-rate distribution of sources, the fluxes of ultrahigh energy cosmic rays and high energy neutrinos are computed and compared with observations, and the explored parameter space for the source characteristics is discussed. We find that, depending on the density of the gas in the source environment, spallation reactions could exceed the outcome in neutrinos from photohadronic interactions in the source environment and in the extragalactic space.

Motivated by properties of tensor networks, we conjecture that an arbitrary gravitating region $a$ can be assigned a generalized entanglement wedge $E\supset a$, such that quasilocal operators in $E$ have a holographic representation in the full algebra generated by quasilocal operators in $a$. The Universe need not be asymptotically flat or anti–de Sitter (AdS), and $a$ need not be asymptotic or weakly gravitating. On a static Cauchy surface $\mathrm{\Sigma }$, we propose that $E$ is the superset of $a$ that minimizes the generalized entropy. We prove that $E$ satisfies a no-cloning theorem and appropriate forms of strong subadditivity and nesting. If $a$ lies near a portion $A$ of the conformal boundary of AdS space, our proposal reduces to the quantum minimal surface prescription applied to $A$. We also discuss possible covariant extensions of this proposal, although none prove completely satisfactory. Our results are consistent with the conjecture that information in $E$ that is spacelike to $a$ in the semiclassical description can nevertheless be recovered from $a$, by microscopic operators that break that description. We thus propose that $E$ quantifies the range of holographic encoding, an important nonlocal feature of quantum gravity, in general spacetimes.

We present nonlinear solutions of Vlasov perturbation theory (VPT), describing gravitational clustering of collisionless dark matter with dispersion and higher cumulants induced by orbit crossing. We show that VPT can be cast into a form that is formally analogous to standard perturbation theory (SPT), but including additional perturbation variables, nonlinear interactions, and a more complex propagation. VPT nonlinear kernels have a crucial decoupling property: for fixed total momentum, the kernels become strongly suppressed when any of the individual momenta cross the dispersion scale into the nonlinear regime. This screening of UV modes allows us to compute nonlinear corrections to power spectra even for cosmologies with very blue power-law input spectra, for which SPT diverges. We compare predictions for the density and velocity divergence power spectra as well as the bispectrum at one-loop order to $N$-body results in a scaling universe with spectral indices $-1\le n_s\le +2$. We find a good agreement up to the nonlinear scale for all cases, with a reach that increases with the spectral index $n_s$. We discuss the generation of vorticity as well as vector and tensor modes of the velocity dispersion, showing that neglecting vorticity when including dispersion would lead to a violation of momentum conservation. We verify momentum conservation when including vorticity, and compute the vorticity power spectrum at two-loop order, necessary to recover the correct large-scale limit with slope $n_w=2$. Comparing to our $N$-body measurements confirms the cross-over from $k^4$ to $k^2$ scaling at large scales. Our results provide a proof-of-principle that perturbative techniques for dark matter clustering can be systematically improved based on the known underlying collisionless dynamics.

The standard perturbation theory (SPT) approach to gravitational clustering is based on a fluid approximation of the underlying Vlasov-Poisson dynamics, taking only the zeroth and first cumulant of the phase-space distribution function into account (density and velocity fields). This assumption breaks down when dark matter particle orbits cross and leads to well-known problems, e.g., an anomalously large backreaction of small-scale modes onto larger scales that compromises predictivity. We extend SPT by incorporating second and higher cumulants generated by orbit crossing. For collisionless matter, their equations of motion are completely fixed by the Vlasov-Poisson system, and thus we refer to this approach as Vlasov Perturbation Theory (VPT). Even cumulants develop a background value, and they enter the hierarchy of coupled equations for the fluctuations. The background values are in turn sourced by power spectra of the fluctuations. The latter can be brought into a form that is formally analogous to SPT, but with an extended set of variables and linear as well as nonlinear terms, that we derive explicitly. In this paper, we focus on linear solutions, which are far richer than in SPT, showing that modes that cross the dispersion scale set by the second cumulant are highly suppressed. We derive stability conditions on the background values of even cumulants from the requirement that exponential instabilities be absent. We also compute the expected magnitude of averaged higher cumulants for various halo models and show that they satisfy the stability conditions. Finally, we derive self-consistent solutions of perturbations and background values for a scaling universe and study the convergence of the cumulant expansion. The VPT framework provides a conceptually straightforward and deterministic extension of SPT that accounts for the decoupling of small-scale modes.

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.