String and 5-brane junctions are shown to succinctly classify all known 8D $\mathcal{N}=1$ string vacua. This requires an extension of the description for ordinary $[p,q]$-7-branes to consistently include $\mathrm{O}{7}^{+}$ planes, which then naturally encodes the dynamics of ${\mathfrak{sp}}_n$ gauge algebras, including their $p$-form center symmetries. Central to this analysis are loop junctions, i.e., strings/5-branes which encircle stacks of 7-branes and $\mathrm{O}{7}^{+}\mathrm{s}$. Loop junctions further signal the appearance of affine symmetries of emergent 9D descriptions at the 8D moduli space’s boundaries. Such limits reproduce all 9D string vacua, including the two disconnected rank (1,1) moduli components.

We propose an approach to describe spontaneous symmetry breaking that does not rely on the order parameter dependent free energy (Landau theory). We use the functional renormalization group evolution of the explicitly broken theory, using a truncation scheme that is compatible with the Ward identities. To represent the symmetry breaking, we propose to use the “Ward ratio” which is zero in the symmetric phase and unity in the broken phase. In this approach a unified scale evolution of the effective potential is applicable in both phases. It is peculiar that the scale evolution is accelerated in the critical regime.

We introduce a background gauge akin to the Landau-DeWitt gauge but deformed by the presence of a gauge parameter for the quantization of Euclidean Yang-Mills theories. In the limit where the background field vanishes, standard linear covariant gauges are recovered. This gauge allows for an explicit investigation of the effects of infinitesimal Gribov copies and their impact to background and gauge parameter dependence of physical correlators. Similarly to linear covariant gauges, the introduction of gauge-invariant dressed fields is essential to restore the Becchi-Rouet-Stora-Tyutin (BRST) symmetry. Hence, we construct a BRST symmetric action in linear covariant background gauges which eliminates regular infinitesimal Gribov copies in analogy to the recently introduced BRST invariant (refined) Gribov-Zwanziger action. The issue of background dependence and its relation to gauge parameter dependence is discussed in the light of nonperturbative effects driven by the elimination of Gribov copies.

In this paper, the connections among one-loop Feynman integrands of a wide range of theories are further investigated. The work includes two parts. First, we construct a new class of differential operators which transmute the one-loop gravitational Feynman integrands to Einstein-Yang-Mills and Yang-Mills Feynman integrands, thus linking these theories together. Second, by using one-loop level transmutation relations, together with some general conditions such as gauge and Lorentz invariance, we derive the expansions of Feynman integrands of certain theories to those of other theories. In particular, we find the Feynman integrands of all theories under consideration can be expanded to integrands of bi-adjoint scalar theory. The unified web for expansions is established, including gravity, Einstein-Yang-Mills theory, Einstein-Maxwell theory, Born-Infeld theory, pure Yang-Mills theory, Yang-Mills-scalar theory, special Yang-Mills-scalar theory, Dirac-Born-Infeld theory, extended Dirac-Born-Infeld theory, special Galileon theory, and nonlinear sigma model. The systematic rules for evaluating coefficients in the expansions are provided, and the duality between transmutation relations and expansions is shown.

Motivated by capturing putative quantum effects at the horizon scale, we model the black hole horizon as a membrane with fluctuations following a Gaussian profile. By extending the membrane paradigm at the semiclassical level, we show that the quantum nature of the black hole horizon implies partially reflective boundary conditions and a frequency-dependent reflectivity. This generically results into a modified quasinormal mode spectrum and the existence of echoes in the postmerger signal. On a similar note, we derive the horizon boundary condition for a braneworld black hole that could originate from quantum corrections on the brane. This scenario also leads to a modified gravitational-wave ringdown. We discuss general implications of these findings for scenarios predicting quantum corrections at the horizon scale.

While recent gravitational wave observations by LIGO and Virgo allow for tests of general relativity in the extreme gravity regime, these observations are still blind to a large swath of phenomena outside these instruments’ sensitivity curves. Future gravitational-wave detectors, such as LISA, will enable probes of longer-duration and lower-frequency events. In particular, LISA will enable the characterization of the nonlinear dynamics of extreme mass-ratio inspirals, when a small compact object falls into a supermassive black hole. In this paper, we study the motion of test particles around spinning black holes in two quadratic gravity theories: scalar Gauss-Bonnet and dynamical Chern-Simons gravity. We show that geodesic trajectories around slowly rotating black holes in these theories are likely to not have a fourth constant of the motion. In particular, we show that Poincaré sections of the orbital phase space present chaotic features that will affect the inspiral of small compact objects into supermassive black holes in these theories. Nevertheless, the characteristic size of these chaotic features is tiny and their location in parameter space is very close to the event horizon of the supermassive black hole. Therefore, the detection of such chaotic features with LISA is likely very challenging, at best.

In this paper, we investigate the Penrose process in the purlieus of the axially symmetric magnetized Reissner-Nordström black hole for both neutral and charged particles. We start with the study of the geometry of the black hole and find the regions where the $g_{tt}$ component of the metric tensor is positive (i.e., $g_{tt}>0$). It is interestingly found that the condition $g_{tt}>0$ is fulfilled not only close to event horizon known as the ergosphere but also far away from the event horizon in the silhouette of potential wells. We also show that as the dimensionless magnetic field $B$ increases the silhouette of potential wells for which $g_{tt}>0$ grows correspondingly and eventually merges with the ergoregion when $B\gtrsim 1.6$. Finally, we investigate the efficiency of the Penrose process for the axially symmetric magnetized black hole case and bring out the effect of magnetic field on it. Further, we also compare our results with the one for Kerr black hole. We show that when the charge $Q$ of the black hole is kept constant, the efficiency of the energy extraction process for the case of neutral particle (i.e., $q/m=0$) first increases and then begins to decrease with rise in the value of $B$ field, in contrast to Kerr black hole where it always increases as the rotation parameter grows. However, for the case of charged particle (i.e., $q\ne 0$) the efficiency always increases with the rise in $B$ field and can go over 100%, when both $B$ and $q/m$ are large enough (say $B\approx 1$ and $q/m>2.2$). It is worth noting that the existence of regions away from the horizon where $g_{tt}>0$ also favors the energy-extraction process away from effect of the black hole. However, the energy extraction from these regions is pure consequence of the magnetic field.

We present a covariant model of a spherically symmetric black hole with corrections motivated by loop quantum gravity. The effective modifications, parametrized by a positive constant $\lambda$, are implemented through a canonical transformation and a linear combination of the constraints of general relativity, in such a way that the theory remains free of anomalies and general relativity is recovered for $\lambda =0$. In addition, the corresponding metric is constructed in a fully covariant way to ensure that gauge transformations on phase space correspond to coordinate changes. The solution for each gauge choice provides a chart and corresponding line element of a spacetime solution whose geometry is unambiguously determined in terms of the parameter $\lambda$ and a constant of motion $m$. For positive values of $m$, the solution is asymptotically flat and contains a globally hyperbolic black-hole/white-hole region with a minimal spacelike hypersurface that replaces the Schwarzschild singularity. The corresponding exterior regions are isometric and, in particular, allow the computation of the Arnowitt-Deser-Misner mass. The procedure to obtain the global causal structure of the solution yields also its maximal analytic extension.

We update cosmological constraints on two decaying dark matter models in light of BOSS-DR12 data analyzed under the effective field theory of large-scale structures (EFTofLSS) formalism, together with Planck, Pantheon and other BOSS measurements of the baryonic acoustic oscillation (BAO). In the first model, a fraction $f_{\mathrm{dcdm}}$ of cold dark matter (CDM) decays into dark radiation (DR) with a lifetime $\tau$. In the second model (recently suggested as a potential resolution to the $S_8$ tension), all the CDM decays with a lifetime $\tau$ into DR and a massive warm dark matter (WDM) particle, with a fraction $ϵ$ of the CDM rest mass energy transferred to the DR. Using numerical codes from the recent literature, we perform the first calculation of the mildly nonlinear (matter and galaxy) power spectra with the EFTofLSS for these two models. In the case of DR products, we obtain the constraints $f_{\mathrm{dcdm}}\lesssim 0.022$ (95% C.L.) for lifetimes shorter than the age of the Universe, and $\tau /f_{\mathrm{dcdm}}\gtrsim 250\mathrm{Gyr}$ in the long-lived regime assuming $f_{\mathrm{dcdm}}\to 1$. We show that Planck data contributes the most to these constraints, with EFTofBOSS providing a marginal improvement over conventional BAO and redshift space distortions ($f{\sigma }_8$) data. In the case of DR and WDM decay products, we find that EFTofBOSS data significantly improves the constraints at 68% C.L. on the CDM lifetime with a $S_8$ prior from KiDS-1000. We show that, in order to fit EFTofBOSS data while lowering $S_8$ to match KiDS-1000, the best-fit model has a longer lifetime $\tau =120\mathrm{Gyr}$, with a larger kick velocity $v_{\mathrm{kick}}/c\simeq ϵ\simeq 1.2\%$, than that without EFTofBOSS ($\tau =43\mathrm{Gyr}$, $ϵ=0.6\%$). We anticipate that future surveys will provide exquisite constraints on such models.

We study a mechanism through which the cosmic dark matter density can be explained simultaneously with the observed baryon asymmetry of the Universe. At the core of our proposal lie the out-of-equilibrium scattering processes of bath particles which are responsible for the production of feebly-interacting dark matter. The same processes violate $CP$, which further leads to an asymmetry between matter and antimatter being generated in the visible sector. We focus on the possibility that these interactions are described through nonrenormalizable operators, which leads to both dark matter and the baryon asymmetry being produced at high temperatures. The mechanism is exemplified by studying two concrete scenarios, one involving scalar and one involving fermion dark matter. We find that in both cases it is, indeed, possible to achieve a common explanation for the dark matter content and the matter-antimatter asymmetry of the Universe, provided that dark matter is in the keV mass range.

How do we appropriately fit a model based on an idealized Friedmann-Lemaître Robertson-Walker spacetime to observations made from a single location in a lumpy universe? We address this question for surveys that measure the imprints of the baryon acoustic oscillation in galaxy distribution and the peak apparent magnitude of the type 1A supernova. These observables are related to the cosmological model through the Alcock-Paczyński parameters and the distance-redshift relation. Using the corresponding inhomogeneous spacetime expressions of these as observed data, we perform a parameter inference assuming that the background Friedmann-Lemaître Robertson-Walker model is the correct model of the Universe. This process allows us to estimate the best fit Hubble rate and the deceleration parameter. We find that the inferred Hubble rate from the monopole of the Alcock-Paczyński parameters is in tension with the Hubble rate determined using the distance-redshift relation. The latter gives the best fit Hubble rate for the cosmological expansion. The constraint on the Hubble rate from the Alcock-Paczyński parameters is contaminated by the environment. When the environmental contribution is restricted to modes in the Hubble flow, we find about (9–12)% discrepancy in the Hubble rate. Finally, we comment on the insufficiency of the method of cosmography in constraining the deceleration parameter.

We present a search for gravitational waves from the coalescence of binaries which contain at least one subsolar-mass component using data from the LIGO and Virgo observatories through the completion of their third observing run. The observation of a merger with a component below $1M_{\odot }$ would be a clear sign of either new physics or the existence of a primordial black hole population; these black holes could also contribute to the dark matter distribution. Our search targets binaries where the primary has mass $M_1$ between 0.1 and $100M_{\odot }$ and the secondary has mass $M_2$ from 0.1 to $1M_{\odot }$ for $M_1<20M_{\odot }$ and 0.01 to $1M_{\odot }$ for $M_1\ge 20M_{\odot }$. Sources with $M_1<7M_{\odot }$, $M_2>0.5M_{\odot }$ are also allowed to have orbital eccentricity up to $e_{10}\sim 0.3$. This search region covers from comparable to extreme mass ratio sources up to ${10}^4:1$. We find no statistically convincing candidates and so place new upper limits on the rate of mergers; our analysis sets the first limits for most subsolar sources with $7M_{\odot }<M_1<20M_{\odot }$ and tightens limits by $\sim 8\times (1.6\times )$ where $M_1>20M_{\odot }$ ($M_1<7M_{\odot }$). Using these limits, we constrain the dark matter fraction to below $0.3(0.7)\%$ for 1 $(0.5)M_{\odot }$ black holes assuming a monochromatic mass function. Due to the high merger rate of primordial black holes beyond the individual source horizon distance, we also use the lack of an observed stochastic background as a complementary probe to limit the dark matter fraction. We find that although the limits are, in general, weaker than those from the direct search, they become comparable at $0.1M_{\odot }$.

The present work derived the robust constraints on annihilating weakly interacting massive particle (WIMP) parameters utilizing new radio observations of M31 as well as new studies of its dark matter distribution and other properties. The characteristics of emission due to dark matter (DM) annihilation were computed in the frame of a 2D galactic model employing GALPROP code adapted specifically for M31. This enabled us to refine various inaccuracies of previous studies on the subject. DM constraints were obtained for two representative annihilation channels: $\chi \chi \to b\overline{b}$ and $\chi \chi \to {\tau }^{+}{\tau }^{-}$. A wide variety of radio data was utilized in the frequency range $\approx (0.1–10)\mathrm{GHz}$. As the result, the thermal WIMP lighter than fiducially $\approx 70\mathrm{GeV}$ for $b\overline{b}$ channel and $\approx 40\mathrm{GeV}$ for ${\tau }^{+}{\tau }^{-}$ was excluded. The corresponding mass threshold uncertainty ranges were estimated to be 20–210 GeV and 18–89 GeV. The obtained exclusions are competitive to those from Fermi-LAT observations of dwarfs and AMS-02 measurements of antiprotons. Our constraints do not exclude the explanation of the $\gamma$-ray outer halo of M31 and the Galactic Center excess by annihilating DM. The thermal WIMP with $m_x\approx 70\mathrm{GeV}$, which explains the outer halo, would make a significant contribution to the nonthermal radio flux in M31 nucleus, fitting well both the spectrum and morphology. And, finally, we questioned the possibility claimed in other studies to robustly constrain heavy thermal WIMP with $m_x>100\mathrm{GeV}$ by radio data on M31.

Rotating black holes (BHs) can efficiently transfer energy to the surrounding environment via superradiance. In particular, when the Compton length of a particle is comparable to the gravitational radius of a BH, the particle’s occupation number can be exponentially amplified. In this work, we investigate the effect of the primordial-black-hole (PBH) superradiant instabilities on the generation of heavy bosonic dark matter (DM) with mass above $\sim 1\mathrm{TeV}$. Additionally, we analyze its interplay with other purely gravitational and therefore unavoidable DM production mechanisms such as Hawking emission and the ultraviolet freeze-in. We find that superradiance can significantly increase the DM density produced by PBHs with respect to the case that only considers Hawking emission, and hence lower initial PBH densities are required.

We investigate the pair production of right-handed neutrinos from the decay of a light $B-L$ scalar in the $U(1{)}_{B-L}$ model. The $B-L$ scalar mixes with the SM Higgs, and the physical scalar is required to be lighter than the observed Higgs. The produced right-handed neutrinos are predicted to be long-lived according to the type-I seesaw mechanism and yield potentially distinct signatures such as displaced-vertex and time-delayed leptons at CMS/ATLAS/LHCb, as well as signatures at the far detectors including CODEX-b, FACET, FASER, MoEDAL-MAPP, and MATHUSLA. We analyze the sensitivity reach at the High-Luminosity LHC for the right-handed neutrinos with masses of 2.5–30 GeV, showing that the active-sterile mixing with muons can be probed to $V_{\mu N}\sim {10}^{-5}$ at CMS/ATLAS/LHCb using the displaced-vertex searches, and 1 order of magnitude lower at MATHUSLA/CMS using time-delayed lepton searches, reaching the parameter space of interest for type-I seesaw mechanisms.

Motivated by tensions between experimental measurements and SM predictions in $b\to s{\ell }^{+}{\ell }^{-}$ transitions, we present the first study of nonminimal flavor-violating minimal supersymmetric Standard Model (MSSM) scenarios contributing to the relevant Wilson coefficients to address the observed anomalies using SuperIso and MARTY. We calculate the full one-loop analytical contributions of the general MSSM to Wilson coefficients relevant for flavor anomalies, together with the anomalous muon magnetic dipole moment $(g-2{)}_{\mu }$. We show that, after imposing theoretical constraints on the flavor-violating parameters, we can find scenarios in agreement with the experimental measurements that can address at the same time the tensions in flavor observables and in $(g-2{)}_{\mu }$.

We show that the effective action that results from integrating out massive Kähler-Dirac fermions propagating on a curved three-dimensional space is a topological gravity theory of Chern-Simons type. In the presence of a domain wall, massless, two-dimensional Kähler-Dirac fermions appear that are localized to the wall. Potential gravitational anomalies arising for these domain wall fermions are canceled via anomaly inflow from the bulk gravitational theory. We also study the invariance of the theory under large gauge transformations. The analysis and conclusions generalize straightforwardly to higher dimensions.

We use principal component analysis to study the hydrodynamic attractor in Yang-Mills kinetic theory undergoing the Bjorken expansion with color glass condensate initial conditions. The late-time hydrodynamic attractor is characterized by a single principal component determining the overall energy scale. How it is reached is governed by the disappearance of single subleading principal component characterizing deviations of the pressure anisotropy, the screening mass and the scattering rate. We find that for wide range of couplings the approach to the hydrodynamic attractor at late times is well described by an exponential. Its decay rate dependence on the coupling turns out to translate into a simple dependence on the shear viscosity to entropy density ratio.

We study critical phenomena associated with a spontaneous chiral symmetry breaking in current-driven nonequilibrium steady states by using holography. We find that the critical exponents $(\gamma ,\nu )$ at the tricritical point are asymmetric between the chiral symmetry restored phase and the broken phase. Their values in the broken phase are different from those of the mean-field theory, whereas other critical exponents are the mean-field values. The phase diagram with respect to temperature and current density shows a reentrant structure: the broken chiral symmetry is restored again at low temperatures in the presence of current density.

A proton is known for its longevity, but what is its lifetime? While many grand unified Theories predict the proton decay with a finite lifetime, we show that the Standard Model (SM) and some versions of ultraunification (which replace sterile neutrinos with new exotic gapped/gapless sectors, e.g., topological or conformal field theory under global anomaly cancellation constraints) with a discrete baryon plus lepton symmetry permit a stable proton. For the 4D SM with Lie group $G_{{\mathrm{SM}}_q}\equiv \frac{\mathrm{SU}(3)\times \mathrm{SU}(2)\times \mathrm{U}(1{)}_{\tilde{Y}}}{{\mathbb{Z}}_q}$ of $q=1$, 2, 3, 6 and $N_f$ families of 15 or 16 Weyl fermions, in addition to the continuous baryon minus lepton $\mathrm{U}(1{)}_{\mathbf{B}-\mathbf{L}}$ symmetry, there is also a compatible discrete baryon plus lepton ${\mathbb{Z}}_{2N_f,\mathbf{B}+\mathbf{L}}$ symmetry. The ${\mathbb{Z}}_{2N_f,\mathbf{B}+\mathbf{L}}$ is discrete due to the Adler-Bell-Jackiw anomaly under the BPST SU(2) instanton. Although both $\mathrm{U}(1{)}_{\mathbf{B}-\mathbf{L}}$ and ${\mathbb{Z}}_{2N_f,\mathbf{B}+\mathbf{L}}$ symmetries are anomaly free under the dynamically gauged $G_{{\mathrm{SM}}_q}$, it is important to check whether they have mixed anomalies with the gravitational background field (spacetime diffeomorphism under Spin group rotation) and higher symmetries (whose charged objects are Wilson electric or ’t Hooft magnetic line operators) of SM. We can also replace the $\mathrm{U}(1{)}_{\mathbf{B}-\mathbf{L}}$ with a discrete variant ${\mathbb{Z}}_{4,X}$ for $X\equiv 5(\mathbf{B}-\mathbf{L})-\frac{2}{3}\tilde{Y}$ of electroweak hypercharge $\tilde{Y}$. We explore a systematic classification of candidate perturbative local and nonperturbative global anomalies of the 4D SM, including all these gauge and gravitational backgrounds, via a cobordism theory, which controls the SM’s deformation class. We discuss the proton stability of the SM and ultraunification in the presence of discrete $\mathbf{B}+\mathbf{L}$ symmetry protection, in particular $(\mathrm{U}(1{)}_{\mathbf{B}-\mathbf{L}}\times {\mathbb{Z}}_{2N_f,\mathbf{B}+\mathbf{L}})/{\mathbb{Z}}_2^F$ or $({\mathbb{Z}}_{4,X}\times {\mathbb{Z}}_{2N_f,\mathbf{B}+\mathbf{L}})/{\mathbb{Z}}_2^F$ with the fermion parity ${\mathbb{Z}}_2^F$.