In scalar-field dark matter scenarios, a scalar-field soliton could form at the center of galactic halos, around the supermassive black holes that sit at the center of galaxies. Focusing on the large scalar-mass limit, where the soliton is formed by the balance between self-gravity and a repulsive self-interaction, we study the infall of the scalar field onto the central Schwarzschild black hole. We derive the scalar-field profile, from the Schwarzschild radius to the large radii dominated by the scalar cloud. We show that the steady state solution selects the maximum allowed flux, with a critical profile that is similar to the transonic solution obtained for the hydrodynamic case. This finite flux, which scales as the inverse of the self-interaction coupling, is small enough to allow the dark matter soliton to survive for many Hubble times.

The flux of unstable secondary cosmic ray nuclei, produced by spallation processes in the interstellar medium, can be used to constrain the residence time of cosmic rays inside the Galaxy. Among them, ${}^{10}\mathrm{Be}$ is especially useful because of its relatively long half-life of 1.39 Myr. In the framework of the diffusive halo model we describe cosmic ray transport taking into account all relevant interaction channels and accounting for the decay of unstable secondary nuclei. We then compare our results with the data collected by the Alpha Magnetic Spectrometer (AMS-02) on board the International Space Station for the flux ratios Be/C, B/C, Be/O, B/O, C/O and Be/B as well as C, N and O absolute fluxes. These measurements, and especially the Be/B ratio, allow us to single out the flux of ${}^{10}\mathrm{Be}$ and infer a best fit propagation time of CRs in the Galaxy. Our results show that, if the cross sections for the production of secondary elements through spallation are taken at face value, AMS-02 measurements are compatible with the standard picture based on CR diffusion in a halo of size $H\gtrsim 5\mathrm{kpc}$. Taking into account the uncertainties in the cross sections, this conclusion becomes less reliable, although still compatible with the standard picture. Implications of our findings for alternative models of CR transport are discussed.

The Probe of Extreme Multimessenger Astrophysics (POEMMA) is a potential NASA Astrophysics Probe-class mission designed to observe ultrahigh-energy cosmic rays (UHECRs) and cosmic neutrinos from space. POEMMA will monitor colossal volumes of the Earth’s atmosphere to detect extensive air showers (EASs) produced by extremely energetic cosmic messengers: UHECRs above 20 EeV over the full sky and cosmic neutrinos above 20 PeV. We focus most of this study on the impact of POEMMA for UHECR science by simulating the detector response and mission performance for EAS from UHECRs. We show that POEMMA will provide a significant increase in the statistics of observed UHECRs at the highest energies over the entire sky. POEMMA will be the first UHECR fluorescence detector deployed in space that will provide high-quality stereoscopic observations of the longitudinal development of air showers. Therefore it will be able to provide event-by-event estimates of the calorimetric energy and nuclear mass of UHECRs. The particle physics in the interactions limits the interpretation of the shower maximum on an event-by-event basis. In contrast, the calorimetric energy measurement is significantly less sensitive to the different possible final states in the early interactions. POEMMA will increase by a factor of 30 fluorescence observations, with accurate measurements of the shower maximum. We study the prospects to discover the origin and nature of UHECRs using expectations for measurements of the energy spectrum, the distribution of arrival direction, and the atmospheric column depth at which the EAS longitudinal development reaches maximum. We also explore supplementary science capabilities of POEMMA through its sensitivity to particle interactions at extreme energies and its ability to detect ultrahigh-energy neutrinos and photons produced by top-down models including cosmic strings and superheavy dark matter particle decay in the halo of the Milky Way.

The nature of dark matter (DM) and how it might interact with the particles of the Standard Model (SM) is an ever-growing mystery. It is possible that the existence of new “dark sector” forces, yet undiscovered, are the key to solving this fundamental problem, and one might hope that in the future such forces might even be “unified” with the ones we already know in some UV-complete framework. In this paper, following a bottom-up approach, we attempt to take the first steps in the construction of such a framework. The much-discussed possibility of the kinetic mixing (KM) of the “dark photon” with the hypercharge gauge boson of the SM via loops of portal matter (PM) fields, charged in both sectors, offers an attractive starting point for these efforts. Given the anticipated finite strength of the KM in a UV-complete theory, the absence of anomalies, and the lifetime constraints on the PM fields arising from cosmic microwave background and nucleosynthesis constraints, PM must behave as vector-like copies of the known SM fermion fields, such as those which appear naturally in, e.g., $E_6$-type models. Within such a setup, the SM and their corresponding partner PM fields would be related by a new $SU(2{)}_I$ gauge symmetry. With this observation as a springboard, we construct a generalization of these ideas where $SU(2{)}_I$ is augmented by an additional $U(1{)}_{I_Y}$ factor so that the light dark photon is the result of a symmetry breaking analogous to the SM, i.e., $SU(2{)}_I\times U(1{)}_{I_Y}\to U(1{)}_D$, but with $U(1{)}_D$ now also broken at the $\lesssim \mathrm{GeV}$ scale. While SM fields are $U(1{)}_D$ singlets, as in the conventional dark photon approach, they transform nontrivially under the full $SU(2{)}_I\times U(1{)}_{I_Y}$ gauge group. This approach leads to numerous interesting signatures, both at low energies and at colliders, and can be viewed as an initial step in the construction of a more UV-complete framework.

We derive Ward identities for the standard model effective field theory using the background-field method. The resulting symmetry constraints on the standard model effective field theory are basis independent, and constrain the perturbative and power-counting expansions. A geometric description of the field connections, and real representations for the $\mathrm{SU}(2{)}_{\mathrm{L}}\times \mathrm{U}(1{)}_{\mathrm{Y}}$ generators, underlies the derivation.

Using a data sample of $(448.1\pm 2.9)\times {10}^6\psi (3686)$ decays collected by the BESIII detector at the Beijing Electron Positron Collider (BEPCII), we observe the decays ${\chi }_{cJ}\to \varphi \varphi \eta (J=0,1,2)$, where the ${\chi }_{cJ}$ are produced via the radiative processes $\psi (3686)\to \gamma {\chi }_{cJ}$. The branching fractions are measured to be $\mathcal{B}({\chi }_{c0}\to \varphi \varphi \eta )=(8.41\pm 0.74\pm 0.62)\times {10}^{-4}$, $\mathcal{B}({\chi }_{c1}\to \varphi \varphi \eta )=(2.96\pm 0.43\pm 0.22)\times {10}^{-4}$, and $\mathcal{B}({\chi }_{c2}\to \varphi \varphi \eta )=(5.33\pm 0.52\pm 0.39)\times {10}^{-4}$, where the first uncertainties are statistical, and the second are systematic. We also search for intermediate states in the $\varphi \varphi$ or $\eta \varphi$ subsystems, but no significant structure is seen due to the limited statistics.

We study spherically symmetric solutions with a scalar field in the shift-symmetric subclass of the Horndeski theory. Constructing an effective energy-momentum tensor of the scalar field based on the two-fluid model, we decompose the scalar field into two components: dark matter and dark energy. We find the dark-matter fluid is pressureless, and its distribution of energy density obeys the inverse-square law. We show the scalar field dark matter can explain the galaxy rotation curve and discuss the time evolution of the dark matter in the cosmic background.

Gravitational waves are a sensitive probe into the structure of compact astronomical objects and the nature of gravity in the strong regime. Modifications of near-horizon physics can imprint on the late time ringdown waveform, leaving behind a train of echoes, from which useful information about new physics in the strong gravity regime can be extracted. We propose a novel approach to compute the rindown waveform and characterize individual echoes perturbatively using the Fredholm determinants, which can be intuitively represented via a diagrammatical scheme. Direct nonperturbative treatments can also be easily implemented for some cases. Numerically, the method is also effective and accurate even for relatively low resources.

We discuss the quantization of vacuum Bianchi I spacetimes in the modified formalism of loop quantum cosmology recently proposed by Dapor and Liegener. This modification is based on a regularization procedure where both the Euclidean and Lorentzian terms of the Hamiltonian are treated independently. Whereas the Euclidean part has already been dealt with in the literature for Bianchi I spacetimes, the Lorentzian one has not yet been represented quantum mechanically. After a brief review of the quantum kinematics and the quantization of the Euclidean sector, we represent the Lorentzian part of the Hamiltonian constraint by an operator according to the factor ordering rules of the Martín-Benito–Mena Marugán–Olmedo prescription. We study the general properties of this quantum operator and the superselection rules derived therefrom, resulting in an action similar to that of the Euclidean operator except that the orientation of the densitized triad is not preserved, a fact which leads to a generic enlargement of the superselection sectors. We conclude with an explanation of the mechanism that prevents this enlargement in the isotropic case and a comment on the effect of alternative prescriptions for the implementation of the improved dynamics.

The dynamics of an anapole seen as dark matter at low energies is studied by solving the Schrödinger-Pauli equation in a potential involving the Dirac delta and its derivatives in three dimensions. This is an interesting mathematical problem that, as far as we know, has not been previously discussed. We show how bound states emerge in this approach, and the scattering problem is formulated (and solved) directly. The total cross section is in full agreement with independent calculations in the standard model.

We present results for the isovector ($p-n$) electromagnetic form factors of the nucleon using 11 ensembles of gauge configurations generated by the MILC Collaboration using the highly improved staggered quark action with $2+1+1$ dynamical flavors. These ensembles span four lattice spacings $a\approx 0.06$, 0.09, 0.12 and 0.15 fm and three values of the light-quark masses corresponding to the pion masses $M_{\pi }\approx 135$, 225 and 315 MeV. High-statistics estimates using the truncated-solver method allow us to quantify various systematic uncertainties and perform a simultaneous extrapolation in the lattice spacing, lattice volume and light-quark masses. We analyze the $Q^2$ dependence of the form factors calculated over the range $0.05\lesssim Q^2\lesssim 1.4{\mathrm{GeV}}^2$ using both the model-independent $z$ expansion and the dipole Ansatz. Our final estimates, using the $z$-expansion fit, for the isovector root-mean-square radius of nucleon are $r_E=0.769(27)(30)\mathrm{fm}$, $r_M=0.671(48)(76)\mathrm{fm}$ and ${\mu }^{p-n}=3.939(86)(138)\mathrm{Bohr}$ magneton. The first error is the combined uncertainty from the leading-order analysis, and the second is an estimate of the additional uncertainty due to using the leading-order chiral-continuum-finite-volume fits. The estimates from the dipole Ansatz, $r_E=0.765(11)(8)\mathrm{fm}$, $r_M=0.704(21)(29)\mathrm{fm}$ and ${\mu }^{p-n}=3.975(84)(125)\mathrm{Bohr}$ magneton, are consistent with those from the $z$ expansion but with smaller errors. Our analysis highlights three points. First, all our data for form factors from the 11 ensembles and existing lattice data on, or close to, physical mass ensembles from other collaborations collapse more clearly onto a single curve when plotted versus $Q^2/M_N^2$ as compared to $Q^2$ with the scale set by quantities other than $M_N$. The difference between these two ways of analyzing the data is indicative of discretization errors, some of which presumably cancel when the data are plotted versus $Q^2/M_N^2$. Second, the size of the remaining deviation of this common curve from the Kelly curve is small and can be accounted for by statistical and possible systematic uncertainties. Third, to improve lattice estimates for $⟨r_E^2⟩$, $⟨r_M^2⟩$ and $\mu$, high-statistics data for $Q^2<0.1{\mathrm{GeV}}^2$ are needed.

We study the consequences of entanglement wedge nesting for conformal field theories (CFTs) with holographic duals. The CFT is formulated on an arbitrary curved background, and we include the effects of curvature-squared couplings in the bulk. In this setup we find necessary and sufficient conditions for entanglement wedge nesting to imply the quantum null energy condition in $d\le 5$, extending its earlier holographic proofs. We also show that the quantum focusing conjecture yields the quantum null energy condition as its nongravitational limit under these same conditions.

Measurements of a weighted energy density average taken in the vacuum state of a conformal field theory in $1+1$ dimensions are randomly distributed with vanishing expectation value. The probability distribution is computed in closed form for two infinite families of averaging functions, generalizing previously known examples. These examples may be further generalized by restriction to a half line. In all cases, the distribution is that of a shifted gamma distribution.

We present new numerical-relativity simulations of eccentric merging black holes with initially antiparallel spins lying in the orbital plane (the so-called superkick configuration). Binary eccentricity boosts the recoil of the merger remnant by up to 25%. The increase in the energy flux is much more modest, and therefore this kick enhancement is mainly due to asymmetry in the binary dynamics. Our findings might have important consequences for the retention of stellar-mass black holes in star clusters and supermassive black holes in galactic hosts.

Black-hole spectroscopy is arguably the most promising tool to test gravity in extreme regimes and to probe the ultimate nature of black holes with unparalleled precision. These tests are currently limited by the lack of a ringdown parametrization that is both robust and accurate. We develop an observable-based parametrization of the ringdown of spinning black holes beyond general relativity, which we dub parspec (parametrized ringdown spin expansion coefficients). This approach is perturbative in the spin, but it can be made arbitrarily precise (at least in principle) through a high-order expansion. It requires $\mathcal{O}(10)$ ringdown detections, which should be routinely available with the planned space mission LISA and with third-generation ground-based detectors. We provide a preliminary analysis of the projected bounds on parametrized ringdown parameters with LISA and with the Einstein Telescope, and discuss extensions of our model that can be straightforwardly included in the future.

We carry out the canonical analysis of the $n$-dimensional Palatini action with or without a cosmological constant ($n\ge 3$) introducing neither second-class constraints nor resorting to any gauge fixing. This is accomplished by providing an expression for the spatial components of the connection that allows us to isolate the nondynamical variables present among them, which can later be eliminated from the action by using their own equation of motion. As a result, we obtain the description of the phase space of general relativity in terms of manifestly $SO(n-1,1)$ [or $SO(n)$] covariant variables subject to first-class constraints only, with no second-class constraints arising during the process. Afterwards, we perform, at the covariant level, a canonical transformation to a set of variables in terms of which the above constraints take a simpler form. Finally, we impose the time gauge and make contact with the $SO(n-1)$ ADM formalism.

We introduce TEOBiResumMultipoles, a nonspinning inspiral-merger-ringdown waveform model built within the effective-one-body (EOB) framework that includes gravitational waveform modes beyond the dominant quadrupole $(\ell ,|m|)=(2,2)$. The model incorporates: (i) an improved Padé resummation of the factorized waveform amplitudes ${\rho }_{\ell m}^{\text{orb}}$ entering the EOB-resummed waveform where the third post-Newtonian (PN), mass-ratio-dependent terms are hybridized with test-mass limit terms up to 6PN relative order for most of the multipoles up to $\ell =6$; (ii) an improved determination of the effective 5PN function $a_6^c(\nu )$ entering the EOB interaction potential done using the most recent, error-controlled, nonspinning numerical relativity (NR) waveforms from the Simulating eXtreme Spacetimes (SXS) Collaboration; and (iii) a NR-informed phenomenological description of the multipolar ringdown. Such representation stems from 19 NR waveforms with mass ratios up to $m_1/m_2=18$ as well as test-mass waveform data, although it does not incorporate mode-mixing effects. The NR-completed higher modes through merger and ringdown considered here are $(\ell ,|m|)=\{(2,1),(3,3),(3,2),(3,1),(4,4),(4,3),(4,2),(4,1),(5,5)\}$. For simplicity, the other subdominant modes, up to $\ell =8$, are approximated by the corresponding, purely analytical, factorized and resummed EOB waveform. To attempt an estimate of (some of) the underlying analytic uncertainties of the model, we also contrast the effect of the 6PN-hybrid Padé-resummed ${\rho }_{\ell m}$’s with the standard $3^{+2}$ PN, Taylor-expanded ones used in previous EOB works. The maximum unfaithfulness $\overline{F}$ against the SXS waveforms including all NR-completed modes up to $\ell =m=5$ is always $\lesssim 2\%$ for binaries with a total mass $M$ in the range $50M_{\odot }\le M\lesssim 200M_{\odot }$. The Padé-resummed multipolar EOB model for nonspinning binaries discussed here defines the foundations of a multipolar EOB waveform model for spin-aligned binaries that will be introduced in a companion paper.

In this paper, we study the weak gravitational deflection angle of relativistic massive particles by the Kerr-like black hole in the bumblebee gravity model. In particular, we focus on weak-field limits and calculate the deflection angle for a receiver and source at a finite distance from the lens. To this end, we use the Gauss-Bonnet theorem of a two-dimensional surface defined by a generalized Jacobi metric. The spacetime is asymptotically nonflat due to the existence of a bumblebee vector field. Thus, the deflection angle is modified and can be divided into three parts: the surface integral of the Gaussian curvature, the path integral of a geodesic curvature of the particle ray, and the change in the coordinate angle. In addition, we also obtain the same results by defining the deflection angle. The effects of the Lorentz breaking constant on the gravitational lensing are analyzed. In particular, we correct a mistake in the previous literature. Furthermore, we consider the finite-distance correction for the deflection angle of massive particles.

Although gravitational waves only interact weakly with matter, their propagation is affected by a gravitational potential. If a gravitational wave source is eclipsed by a star, measuring these perturbations provides a way to directly measure the distribution of mass throughout the stellar interior. We compute the expected Shapiro time delay, amplification, and deflection during an eclipse, and show how this can be used to infer the mass distribution of the eclipsing body. We identify continuous gravitational waves from neutron stars as the best candidates to detect this effect. When the Sun eclipses a far-away source, depending on the depth of the eclipse the time delay can change by up to $\sim 0.034\mathrm{ms}$, the gravitational-wave strain amplitude can increase by $\sim 4\%$, and the apparent position of the source in the sky can vary by $4^{\prime \prime }$. Accreting neutron stars with Roche-lobe filling companion stars have a high probability of exhibiting eclipses, producing similar time delays but undetectable changes in amplitude and sky location. Even for the most rapidly rotating neutron stars, this time delay only corresponds to a few percent of the phase of the gravitational wave, making it an extremely challenging measurement. However, if sources of continuous gravitational waves exist just below the limit of detection of current observatories, next-generation instruments will be able to observe them with enough precision to measure the signal of an eclipsing star. Detecting this effect would provide a new direct probe to the interior of stars, complementing asteroseismology and the detection of solar neutrinos.