At linear order the only expected source of a curl-like, B mode, polarization pattern in the cosmic microwave background (CMB) is primordial gravitational waves. At second-order B modes are also produced from purely scalar, density, initial conditions. Unlike B modes from primordial gravitational waves, these B modes are expected to be non-Gaussian and not independent from the temperature and gradientlike polarization, E mode, CMB anisotropies. We find that the three point function between a second-order B mode and two first-order T/E modes is a powerful probe of second-order B modes. We focus on the contribution to the three point function arising from nonlinear evolution and scattering processes before the end of recombination as this provides new information on the universe at $z>1000$. We find that this contribution can be separated from the other contributions and is measurable at $\sim 2.5\sigma$ by CMB experiments with noise levels of $\sim 1\mu$ Karcmin and delensing efficiencies $\ge 90\%$, such as the proposed PICO satellite. We show that approximately half of the total signal arises from nonlinearly induced vector and tensor metric perturbations, as evaluated in the Newtonian gauge. This bispectrum is a unique probe of these perturbations in the CMB, as their contribution to the power spectrum is suppressed. An important feature of this bispectrum is that the detectability will increase with decreasing experimental noise, in the absence of primordial B modes, provided that delensing efficiencies improve in parallel.

We study inflationary universes with an SU(3) gauge field coupled to an inflaton through a gauge kinetic function. Although the SU(3) gauge field grows at the initial stage of inflation due to the interaction with the inflaton, nonlinear self-couplings in the kinetic term of the gauge field become significant and cause nontrivial dynamics after sufficient growth. We investigate the evolution of the SU(3) gauge field numerically and reveal attractor solutions in the Bianchi type-I spacetime. In general cases where all the components of the SU(3) gauge field have the same magnitude initially, they all tend to decay eventually because of the nonlinear self-couplings. Therefore, the cosmic no-hair conjecture generically holds in a mathematical sense. Practically, however, the anisotropy can be generated transiently in the early Universe. Moreover, we find particular cases for which several components of the SU(3) gauge field survive against the nonlinear self-couplings. It occurs due to flat directions in the potential of a gauge field for Lie groups whose rank is higher than one. Thus, an SU(2) gauge field has a specialty among general non-Abelian gauge fields.

Classical and quantum Friedmann-Lemaître-Robertson-Walker universes filled with noninteracting radiation and dust fluids are considered in the framework of Hořava-Lifshitz gravity theory. The Hořava-Lifshitz theory is set in its projectable version and without the detailed balance condition. Canonical quantization is performed in the Wheeler-DeWitt approach of quantum cosmology for a minisuperspace model in light of the de Broglie–Bohm interpretation of quantum mechanics. The main results are analytical solutions for nonsingular quantum bounce and cyclic universes for open and closed spatial sections in terms of the parameters of Hořava-Lifshitz theory.

The Hubble tension might be resolved by injecting a new energy component, called early dark energy (EDE), prior to recombination. An anti–de Sitter (AdS) phase around recombination can make the injected energy decay faster, which thus allows a higher EDE fraction (so larger $H_0$) while prevents degrading the CMB fit. In this work, we test the AdS-EDE model with CMB and large-scale structure (LSS) data. Our CMB dataset consists of low-$\ell$ part of Planck TT spectrum and SPTpol polarization and lensing measurements, since this dataset predicts the CMB lensing effect consistent with $\mathrm{\Lambda }\mathrm{CDM}$ expectation. Combining it with BAO and Pantheon data, we find the best fit values $H_0=71.92\mathrm{km}/\mathrm{s}/\mathrm{Mpc}$ and $H_0=73.29\mathrm{km}/\mathrm{s}/\mathrm{Mpc}$ without and with the SH0ES prior, respectively. Including cosmic shear and galaxy clusters data, we have $H_0=71.87\mathrm{km}/\mathrm{s}/\mathrm{Mpc}$ and $S_8=0.785$, i.e., only $1.3\sigma$ discrepancy with direct $S_8$ measurement.

Despite significant efforts over the past decade, the origin of the cosmic ray positron excess has still not been unambiguously established. A popular class of candidate sources are pulsars or pulsar wind nebulae but these cannot also account for the observed hard spectrum of cosmic ray antiprotons. We revisit the alternative possibility that the observed high-energy positrons are secondaries created by spallation in supernova remnants during the diffusive shock acceleration of the primary cosmic rays, which are further accelerated by the same shocks. The resulting source spectrum of positrons at high energies is then naturally harder than that of the primaries, as is the spectrum of other secondaries such as antiprotons. We present the first comprehensive investigation of the full parameter space of this model—both the source parameters as well as those governing galactic transport. Various parametrizations of the cross sections for the production of positrons and antiprotons are considered, and the uncertainty in the model parameters discussed. We obtain an excellent fit to recent precision measurements by AMS-02 of cosmic ray protons, helium, positrons, and antiprotons, as well as of various primary and secondary nuclei. This model thus provides an economical explanation of the spectra of all secondary species—from a single well-motivated population of sources.

Asymptotically nonlocal field theories represent a sequence of higher-derivative theories whose limit point is a ghost-free, infinite-derivative theory. Here we extend this framework, developed previously in a theory of real scalar fields, to gauge theories. We focus primarily on asymptotically nonlocal scalar electrodynamics, first identifying equivalent gauge-invariant formulations of the Lagrangian, one with higher-derivative terms and the other with auxiliary fields instead. We then study mass renormalization of the complex scalar field in each formulation, showing that an emergent nonlocal scale (i.e., one that does not appear as a fundamental parameter in the Lagrangian of the finite-derivative theories) regulates loop integrals as the limiting theory is approached, so that quadratic divergences can be hierarchically smaller than the lightest Lee-Wick partner. We conclude by making preliminary remarks on the generalization of our approach to non-Abelian theories, including an asymptotically nonlocal standard model.

The lattice compact Abelian Higgs model is a nonperturbative regularized formulation of low-energy scalar quantum electrodynamics. In $1+1$ dimensions, this model can be quantum simulated using a ladder-shaped optical lattice with Rydberg-dressed atoms [J. Zhang et al., Phys. Rev. Lett. 121, 223201 (2018)]. In this setup, one spatial dimension is used to carry the angular momentum of the quantum rotors. One can use truncations corresponding to spin-2 and spin-1 to build local Hilbert spaces associated with the links of the lattice. We argue that ladder-shaped configurable arrays of Rydberg atoms can be used for the same purpose. We make concrete proposals involving two and three Rydberg atoms to build one local spin-1 space (a qutrit). We show that the building blocks of the Hamiltonian calculations are models with one and two spins. We compare target and simulators using perturbative and numerical methods. The two-atom setup provides an easily controllable simulator of the one-spin model while the three-atom setup involves solving nonlinear equations. We discuss approximate methods to couple two spin-1 spaces. The article provides analytical and numerical tools necessary to design and build the proposed simulators with current technology.

We obtain the distribution amplitude (DA) of the pion from its light-front wave functions in the basis light-front quantization framework. This light-front wave function of the pion is given by the lowest eigenvector of a light-front effective Hamiltonian consisting a three-dimensional confinement potential and the color-singlet Nambu-Jona-Lasinion interaction both between the constituent quark and antiquark. The quantum chromodynamics evolution of the DA is subsequently given by the perturbative Efremov-Radyushkin-Brodsky-Lepage evolution equation. Based on this DA, we then evaluate the singly and doubly virtual transition form factors in the spacelike region for ${\pi }^0\to {\gamma }^{*}\gamma$ and ${\pi }^0\to {\gamma }^{*}{\gamma }^{*}$ processes using the hard-scattering formalism. Our prediction for the pion-photon transition form factor agrees well with data reported by the Belle Collaboration. However, in the large $Q^2$ region it deviates from the rapid growth reported by the BABAR Collaboration. Meanwhile, our result on the ${\pi }^0\to {\gamma }^{*}{\gamma }^{*}$ transition form factor is also consistent with other theoretical approaches and agrees with the scaling behavior predicted by perturbative quantum chromodynamics.

Based on $14.7{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ annihilation data collected with the BESIII detector at the BEPCII collider at 17 different center-of-mass energies between 3.7730 GeV and 4.5995 GeV, Born cross sections of the two processes $e^{+}{e}^{-}\to p\overline{p}\eta$ and $e^{+}{e}^{-}\to p\overline{p}\omega$ are measured for the first time. No indication of resonant production through a vector state $V$ is observed, and upper limits on the Born cross sections of $e^{+}{e}^{-}\to V\to p\overline{p}\eta$ and $e^{+}{e}^{-}\to V\to p\overline{p}\omega$ at the 90% confidence level are calculated for a large parameter space in resonance masses and widths. For the current world average parameters of the $\psi (4230)$ of $m=4.2187\mathrm{GeV}/c^2$ and $\mathrm{\Gamma }=44\mathrm{MeV}$, we find upper limits on resonant production of the $p\overline{p}\eta$ and $p\overline{p}\omega$ final states of 7.5 pb and 10.4 pb at the 90% CL, respectively.

The current most stringent constraints for the existence of sub-GeV dark matter coupling to Standard Model via a massive vector boson $A^{\prime }$ were set by the NA64 experiment for the mass region $m_{A^{\prime }}\lesssim 250\mathrm{MeV}$, by analyzing data from the interaction of $2.84\times {10}^{11}$ 100-GeV electrons with an active thick target and searching for missing-energy events. In this work, by including $A^{\prime }$ production via secondary positron annihilation with atomic electrons, we extend these limits in the 200–300 MeV region by almost an order of magnitude, touching for the first time the dark matter relic density constrained parameter combinations. Our new results demonstrate the power of the resonant annihilation process in missing energy dark-matter searches, paving the road to future dedicated $e^{+}$ beam efforts.

Self-duality is a very important concept in the study and applications of topological solitons in many areas of physics. The rich mathematical structures underlying it lead, in many cases, to the development of exact and nonperturbative methods. We present a generalization of the Yang-Mills-Higgs system by the introduction of scalar fields assembled in a symmetric and invertible matrix $h$ of the same dimension as the gauge group. The coupling of such new fields to the gauge and Higgs fields is made by replacing the Killing form, in the contraction of the group indices, with the matrix $h$ in the kinetic term for the gauge fields and with its inverse in the Higgs field kinetic term. The theory is conformally invariant in the three-dimensional space ${\mathbb{R}}^3$. An important aspect of the model is that for practically all configurations of the gauge and Higgs fields the new scalar fields adjust themselves to solve the modified self-duality equations. We construct solutions using a spherically symmetric Ansatz and show that the ’t Hooft-Polyakov monopole becomes a self-dual solution of such modified Yang-Mills-Higgs systems. We use an Ansatz based on the conformal symmetry to construct vacuum solutions presenting nontrivial toroidal magnetic fields.

Twistors appear to provide a satisfactory treatment of angular momentum for gravitationally radiating systems. The approach is manifestly Bondi-Metzner-Sachs (BMS) invariant, and there are no supertranslation ambiguities. The resulting definitions of center of mass and spin are appealing: unphysical contributions from bad cuts are canceled off from the center of mass, and the spin appears formally as a displacement of the center of mass into the complex. For transitions between asymptotically Minkowskian regimes (nonradiative regimes with purely electric Bondi shear), when there is no supertranslation offset (equivalently, radation memory) between the regimes, the results are in agreement with those deducible from other approaches. However, when there is an offset, the results are different. The twistor-derived change-of-origin formula is closely parallel to the special-relativistic one, with an algebraic cross-product between the energy-momentum and a direction-dependent translation derived from the supertranslation. (No supermomenta appear.) There is also a “longitudinal” contribution to the emitted angular momentum (one sensitive to the total energy-momentum and not just the emitted energy-momentum), and terms which are both linear and cubic in the gravitational radiation (whereas BMS-based definitions give purely quadratic contributions). The first-order terms mean that the supertranslation offsets can contribute to the exchange of angular momentum with gravitational radiation, even in weak-field limits. This is illustrated with a simple almost-special-relativistic model.

Recently, an analytical solution in Einstein-aether theory was presented explicitly in isotropic coordinates. It is characterized by a mass parameter $m$ and a combined coupling constant $c_{14}$. By a coordinate transformation, we verify this solution is equivalent to the previously known static aether solution. Assuming photons couple minimally to aether and gravity, we investigate the photon sphere and shadow of the solution by varying $c_{14}$. Results are compared with those of the Schwarzschild black hole.

Virial (aka scaling) identities are integral identities that are useful for a variety of purposes in nonlinear field theories, including establishing no-go theorems for solitonic and black hole solutions, as well as for checking the accuracy of numerical solutions. In this paper, we provide a pedagogical rationale for the derivation of such integral identities, starting from the standard variational treatment of particle mechanics. In the framework of one-dimensional (1D) effective actions, the treatment presented here yields a set of useful formulas for computing virial identities in any field theory. Then, we propose that a complete treatment of virial identities in relativistic gravity must take into account the appropriate boundary term. For General Relativity this is the Gibbons-Hawking-York boundary term. We test and confirm this proposal with concrete examples. Our analysis here is restricted to spherically symmetric configurations, which yield 1D effective actions (leaving higher-D effective actions and in particular the axially symmetric case to a companion paper). In this case, we show that there is a particular “gauge” choice, i.e. a choice of coordinates and parametrizing metric functions, that simplifies the computation of virial identities in General Relativity, making both the Einstein-Hilbert action and the Gibbons-Hawking-York boundary term noncontributing. Under this choice, the virial identity results exclusively from the matter action. For generic “gauge” choices, however, this is not the case.

Cross-correlating cosmic microwave background (CMB) lensing and galaxy clustering has been shown to greatly improve the constraints on the local primordial non-Gaussianity (PNG) parameter $f_{\mathrm{NL}}$ by reducing sample variance and also parameter degeneracies. To model the full use of the 3D information of galaxy clustering, we forecast $f_{\mathrm{NL}}$ measurements using the decomposition in the spherical Fourier-Bessel (SFB) basis, which can be naturally cross-correlated with 2D CMB lensing in spherical harmonics. In the meantime, such a decomposition would also enable us to constrain the growth rate of structure, a probe of gravity, through the redshift-space distortion (RSD). As a comparison, we also consider the tomographic spherical harmonic (TSH) analysis of galaxy samples with different bin sizes. Assuming galaxy samples that mimic a few future surveys, we perform Fisher forecasts using linear modes for $f_{\mathrm{NL}}$ and the growth-rate exponent $\gamma$, marginalized over standard $\mathrm{\Lambda }$ cold dark matter ($\mathrm{\Lambda }\mathrm{CDM}$) cosmological parameters and two nuisance parameters that account for clustering bias and magnification bias. Compared to TSH analysis using only one bin, SFB analysis could improve $\sigma (f_{\mathrm{NL}})$ by a factor of 3 to 12 thanks to large radial modes. With future wide-field and high-redshift photometric surveys like the LSST, the constraint $\sigma (f_{\mathrm{NL}})<1$ could be achieved using linear angular multipoles up to ${\ell }_{\min }\simeq 20$. Compared to using galaxy autopower spectra only, joint analyses with CMB lensing could improve $\sigma (\gamma )$ by a factor of 2 to 5 by reducing degeneracies with other parameters, especially the clustering bias. For future spectroscopic surveys like the DESI or Euclid, using linear scales, $\gamma$ could be constrained to 3% precision, assuming the GR fiducial value.

Based on a 14-moment closure for nonresistive (general-) relativistic viscous plasmas, we describe a new numerical scheme that is able to handle all first-order dissipative effects (heat conduction, bulk and shear viscosities), as well the anisotropies induced by the presence of magnetic fields. The latter is parametrized in terms of a thermal gyrofrequency or, equivalently, a thermal Larmor radius and allows to correctly capture the thermal Hall effect. By solving an extended Israel-Stewart-like system for the dissipative quantities that enforces algebraic constraints via stiff-relaxation, we are able to cast all first-order dissipative terms in flux-divergence form. This allows us to apply traditional high-resolution shock capturing methods to the equations, making the system suitable for the numerical study of highly turbulent flows. We present several numerical tests to assess the robustness of our numerical scheme in flat spacetime. The 14-moment closure can seamlessly interpolate between the highly collisional limit found in neutron star mergers, and the highly anisotropic limit of relativistic Braginskii magnetohydrodynamics appropriate for weakly collisional plasmas in black-hole accretion problems. We believe that this new formulation and numerical scheme will be useful for a broad class of relativistic magnetized flows.

As the sensitivity and observing time of gravitational-wave detectors increase, a more diverse range of signals is expected to be observed from a variety of sources. Especially, long-lived gravitational-wave transients have received interest in the last decade. Because most long-duration signals are poorly modeled, detection must rely on generic search algorithms, which make few or no assumptions on the nature of the signal. However, the computational cost of those searches remains a limiting factor, which leads to suboptimal sensitivity. Several detection algorithms have been developed to cope with this issue. In this paper, we present a new data analysis pipeline to search for unmodeled long-lived transient gravitational-wave signals with duration between 10 and ${10}^3\mathrm{s}$, based on an excess cross-power statistic in a network of detectors. The pipeline implements several new features that are intended to reduce computational cost and increase detection sensitivity for a wide range of signal morphologies. The method is generalized to a network of an arbitrary number of detectors and aims to provide a stable interface for further improvements. Comparisons with a previous implementation of a similar method on simulated and real gravitational-wave data show an overall increase in detection efficiency for all but one signal morphologies tested and a computing time reduced by at least a factor 10.

We perform a global analysis of three-body charmless hadronic decays $B\to V{P}_3\to P_1{P}_2{P}_3$ in the perturbative QCD (PQCD) approach, where $V$ denotes an intermediate vector resonance, and $P_i$, $i=1$, 2, 3 denote final-state pseudoscalar mesons. Fitting the PQCD factorization formulas at leading order in the strong coupling ${\alpha }_s$ to measured branching ratios and direct $CP$ asymmetries, we determine the Gegenbauer moments in the two-meson distribution amplitudes (DAs) for the meson pairs $P_1{P}_2=\pi \pi ,K\pi ,KK$. The fitted Gegenbauer moments are then employed to make predictions for those observables, whose data are excluded in the fit due to larger experimental uncertainties. A general consistency between our predictions and data is achieved, which hints at the validity of the PQCD formalism for the above three-body $B$-meson decays and the universality of the nonperturbative two-meson DAs. The obtained two-meson DAs can be applied to PQCD studies of other multi-body $B$-meson decays involving the same meson pairs. We also attempt to determine the dependence of the Gegenbauer moments on the meson-pair invariant mass, and demonstrate that this determination is promising, when data become more precise.

We study an inevitable cosmological consequence in PeV-scale SUSY-breaking scenarios. We focus on the SUSY-breaking scale corresponding to the gravitino mass $m_{3/2}=100\mathrm{eV}–1\mathrm{keV}$. We argue that the presence of an early matter-dominated era and the resulting entropy production are requisite for the Universe with this gravitino mass. We infer the model-independent minimum amount of the entropy production $\mathrm{\Delta }$ by requiring that the number of dwarf satellite galaxies $N_{\mathrm{sat}}$ in the Milky Way exceed the currently observed value, i.e., $N_{\mathrm{sat}}\gtrsim 63$. This entropy production is inevitably imprinted on the primordial gravitational waves (PGWs) produced during the inflationary era. We study how the information on the value of $\mathrm{\Delta }$ and the time of entropy production are encoded in the PGW spectrum ${\mathrm{\Omega }}_{\mathrm{GW}}$. If the future GW surveys observe a suppression feature in the PGW spectrum for the frequency range $\mathcal{O}({10}^{-10})\mathrm{Hz}\lesssim f_{\mathrm{GW}}\lesssim \mathcal{O}({10}^{-5})\mathrm{Hz}$, it works as a smoking gun for PeV SUSY-breaking scenarios. Even if they do not, our study can be used to rule out all such scenarios.