In [1] the horizon fluffs proposal is put forward to identify microstates of generic nonextremal three-dimensional Bañados–Teitelboim–Zanelli (BTZ) black holes. The proposal is that black hole microstates, the horizon fluffs, are certain near horizon soft hairs which are not in the coadjoint orbits of the asymptotic Virasoro algebra associated with the BTZ black holes. It is also known that ${\mathrm{AdS}}_3$ Einstein gravity has more general black hole solutions than the BTZ family which are generically described by two periodic, but otherwise arbitrary, holomorphic and antiholomorphic functions. We show that these general ${\mathrm{AdS}}_3$ black holes which are typically conformal descendants of the BTZ black holes and are characterized by the associated Virasoro coadjoint orbits, appear as coherent states in the asymptotic symmetry algebra corresponding to the black hole family. We apply the horizon fluffs proposal to these generic ${\mathrm{AdS}}_3$ black holes and identify the corresponding microstates. We then perform microstate counting and compute the entropy. The entropy appears to be an orbit invariant quantity, providing an important check for the horizon fluffs proposal.

Detecting the imprint of inflationary gravitational waves on the $B$-mode polarization of the cosmic microwave background (CMB) is one of the main science cases for current and next-generation CMB experiments. In this work we explore some of the challenges that ground-based facilities will have to face in order to carry out this measurement in the presence of galactic foregrounds and correlated atmospheric noise. We present forecasts for stage-3 (S3) and planned stage-4 (S4) experiments based on the analysis of simulated sky maps using a map-based Bayesian foreground-cleaning method. Our results thus consistently propagate the uncertainties on foreground parameters such as spatially varying spectral indices, as well as the bias on the measured tensor-to-scalar ratio $r$ caused by an incorrect modeling of the foregrounds. We find that S3 and S4-like experiments should be able to put constraints on $r$ of the order $\sigma (r)=(0.5–1.0)\times {10}^{-2}$ and $\sigma (r)=(0.5–1.0)\times {10}^{-3}$ respectively, assuming instrumental systematic effects are under control. We further study deviations from the fiducial foreground model, finding that, while the effects of a second polarized dust component would be minimal on both S3 and S4, a 2% polarized anomalous dust emission component would be clearly detectable by stage-4 experiments.

We present two methods for determining the significance of a stochastic gravitational-wave (GW) background affecting a pulsar-timing array, where detection is based on evidence for quadrupolar spatial correlations between pulsars. Rather than constructing noise simulations, we eliminate the GWB spatial correlations in the true data sets to assess detection significance with all real data features intact. In our first method, we perform random phase shifts in the signal-model basis functions. This phase shifting eliminates signal phase coherence between pulsars, while keeping the statistical properties of the pulsar timing residuals intact. We then explore a method to null correlations between pulsars by using a “scrambled” overlap-reduction function in the signal model for the array. This scrambled function is orthogonal to what we expect of a real GW background signal. We demonstrate the efficacy of these methods using Bayesian model selection on a set of simulated data sets that contain a stochastic GW signal, timing noise, undiagnosed glitches, and uncertainties in the Solar system ephemeris. Finally, we introduce an overarching formalism under which these two techniques are naturally linked. These methods are immediately applicable to all current pulsar-timing array data sets, and should become standard tools for future analyses.

We describe a stream-based analysis pipeline to detect gravitational waves from the merger of binary neutron stars, binary black holes, and neutron-star–black-hole binaries within $\sim 1$ min of the arrival of the merger signal at Earth. Such low-latency detection is crucial for the prompt response by electromagnetic facilities in order to observe any fading electromagnetic counterparts that might be produced by mergers involving at least one neutron star. Even for systems expected not to produce counterparts, low-latency analysis of the data is useful for deciding when not to point telescopes, and as feedback to observatory operations. Analysts using this pipeline were the first to identify GW151226, the second gravitational-wave event ever detected. The pipeline also operates in an offline mode, in which it incorporates more refined information about data quality and employs acausal methods that are inapplicable to the online mode. The pipeline’s offline mode was used in the detection of the first two gravitational-wave events, GW150914 and GW151226, as well as the identification of a third candidate, LVT151012.

We study the relation between the continuum threshold $s_0$ within finite energy sum rules and the trace of the Polyakov loop $\mathrm{\Phi }$ in the framework of a nonlocal SU(2) chiral quark model, establishing a contact between both deconfinement order parameters at finite temperature $T$ and chemical potential $\mu$. In our analysis, we also include the order parameter for the chiral symmetry restoration, the chiral quark condensate. We found that $s_0$ and $\mathrm{\Phi }$ provide us with the same information for the deconfinement transition, both for the zero and finite chemical potential cases. At zero density, the critical temperatures for both quantities coincide exactly and, at finite $\mu$ both order parameters provide evidence for the appearance of a quarkyonic phase.

Many-body systems with chiral fermions can exhibit novel transport phenomena that violate parity and time-reversal symmetries, such as the chiral magnetic effect, the anomalous Hall effect, and the anomalous generation of charge. Based on the Maxwell-Chern-Simons electrodynamics, we examine some electromagnetic and optical properties of such systems including the electrostatics, the magnetostatics, the propagation of electromagnetic waves, the novel optical effects, etc.

We analyze the prospects for detection of light sub-GeV dark matter produced in experiments designed to study the properties of neutrinos, such as MiniBooNE, T2K, SHiP, DUNE etc. We present an improved production model, when dark matter couples to hadronic states via a dark photon or baryonic vector mediator, incorporating bremsstrahlung of the dark vector. In addition to elastic scattering, we also study signatures of light dark matter undergoing deep inelastic or quasielastic $\mathrm{NC}{\pi }^0$-like scattering in the detector producing neutral pions, which for certain experiments may provide the best sensitivity. Supplemental Material provides extensive documentation for a publicly available simulation tool BdNMC that can be applied to determine the hidden sector dark matter production and scattering rate at a range of proton fixed target experiments.

We revisit a recent solution to the flavor hierarchy problem based on the paradigm that Yukawa couplings are, rather than fundamental constants, effective low energy couplings radiatively generated by interactions in a hidden sector of the theory. In the present paper we show that the setup required by this scenario can be set by gauge invariance alone, provided that the standard model gauge group be extended to the left-right symmetric group of $SU(2{)}_L\times SU(2{)}_R\times U(1{)}_Y$. The simplest scheme in which Yukawa couplings are forbidden at the tree-level organises the right-handed fermions into doublets and presents an additional Higgs $SU(2{)}_R$ doublet, responsible for the spontaneous breaking of the $SU(2{)}_R$ gauge sector. The flavor and chiral symmetry breaking induced by the $SU(2{)}_R$ breaking is transferred at the one-loop level to the standard model via the dynamics of the hidden sector, which effectively regulates the spread of the effective Yukawa couplings. The emerging left-right symmetric framework recovers additional appealing features typical of these models, allowing for instance to identify the hypercharges of the involved fermions with their $B-L$ charges and offering a straightforward solution to the strong $CP$ problem. The scheme gives rise to a distinguishing phenomenology that potentially can be tested at the LHC and future colliders through the same interactions that result in the radiative generation of Yukawa couplings, as well as by exploiting the properties of the additional $SU(2{)}_R$ Higgs doublet.

We investigate spin effects in four-quark systems consisting of two heavy antibottom quarks and two light up/down quarks. To this end, we use the Born-Oppenheimer approximation. We utilize potentials of two static antiquarks in the presence of two quarks of finite mass computed via lattice QCD and solve a coupled-channel Schrödinger equation for the antibottom-antibottom separation. Without taking heavy quark spins into account, this approach predicted a $ud\overline{b}\overline{b}$ tetraquark bound state with quantum numbers $I(J^P)=0(1^{+})$. We now extend this Born-Oppenheimer approach with coupled-channel Schrödinger equations, allowing us to incorporate effects due to the heavy $\overline{b}$ spins. We confirm the existence of the $ud\overline{b}\overline{b}$ tetraquark.

In principle, the strong-interaction sector of the standard model is characterized by a unique renormalization-group-invariant (RGI) running interaction and a unique form for the dressed–gluon-quark vertex, ${\mathrm{\Gamma }}_{\mu }$; but, whilst much has been learnt about the former, the latter is still obscure. In order to improve this situation, we use a RGI running-interaction that reconciles top-down and bottom-up analyses of the gauge sector in quantum chromodynamics (QCD) to compute dressed-quark gap equation solutions with 1,660,000 distinct Ansätze for ${\mathrm{\Gamma }}_{\mu }$. Each one of the solutions is then tested for compatibility with three physical criteria and, remarkably, we find that merely 0.55% of the solutions survive the test. Evidently, even a small selection of observables places extremely tight bounds on the domain of realistic vertex Ansätze. This analysis and its results should prove useful in constraining insightful contemporary studies of QCD and hadronic phenomena.

Recently a new class of asymptotically AdS ultra-spinning black holes has been constructed with a noncompact horizon of finite area [R. A. Hennigar, D. Kubiznak, and R. B. Mann, Super-Entropic Black Holes, Phys. Rev. Lett. 115, 031101 (2015).], in which the asymptotic rotation is effectively boosted to the speed of light. We employ this technique for four-dimensional $U(1{)}^4$ and five-dimensional $U(1{)}^3$ gauged supergravity black holes. The obtained new exact black hole solutions for both cases possess a noncompact horizon; their topologies are a sphere with two punctures. We then demonstrate that the ultra-spinning limit commutes with the extremality condition as well as the near horizon limit for both black holes. We also show that the near horizon extremal geometries of the resulting ultra-spinning gauged supergravity black holes lead to the well-known result which contains an ${\mathrm{AdS}}_2$ throat. We then obtain the $[(d-1)/2]$ central charges of the dual CFTs. By assuming the Cardy formula, we show that despite the noncompactness of the horizon, microscopic entropy of the dual CFT is precisely equivalent to the Bekenstein-Hawking entropy.

The properties of the multisoliton solutions of the ($2+1$)-dimensional Maxwell-Chern-Simons-Skyrme model are investigated numerically. Coupling to the Chern-Simons term allows for existence of the electrically charge solitons which may also carry magnetic fluxes. Two particular choices of the potential term is considered: (i) the weakly bounded potential and (ii) the double vacuum potential. In the absence of gauge interaction in the former case the individual constituents of the multisoliton configuration are well separated, while in the latter case the rotational invariance of the configuration remains unbroken. It is shown that coupling of the planar multi-Skyrmions to the electric and magnetic field strongly affects the pattern of interaction between the constituents. We analyze the dependency of the structure of the solutions, the energies, angular momenta, electric and magnetic fields of the configurations on the gauge coupling constant $g$, and the electric potential. It is found that, generically, the coupling to the Chern-Simons term strongly affects the usual pattern of interaction between the skyrmions, in particular the electric repulsion between the solitons may break the multisoliton configuration into partons. We show that as the gauge coupling becomes strong, both the magnetic flux and the electric charge of the solutions become quantized although they are not topological numbers.

We propose here a specific criterion to address the existence or otherwise of Kerr naked singularities, in terms of the precession of the spin of a test gyroscope due to the frame dragging by the central spinning body. We show that there is indeed an important characteristic difference in the behavior of gyro spin precession frequency in the limit of approach to these compact objects, and this can be used, in principle, to differentiate the naked singularity from a black hole. Specifically, if gyroscopes are fixed all along the polar axis up to the horizon of a Kerr black hole, the precession frequency becomes arbitrarily high, blowing up as the event horizon is approached. On the other hand, in the case of naked singularity, this frequency remains always finite and well behaved. Interestingly, this behavior is intimately related to and is governed by the geometry of the ergoregion in each of these cases, which we analyze here. One intriguing behavior that emerges is, in the Kerr naked singularity case, the Lense-Thirring precession frequency (${\mathrm{\Omega }}_{\mathrm{LT}}$) of the gyroscope due to frame-dragging effect decreases as (${\mathrm{\Omega }}_{\mathrm{LT}}\propto r$) after reaching a maximum, in the limit of $r=0$, as opposed to $r^{-3}$ dependence in all other known astrophysical cases.

It is well known that extracting viable testable predictions out of fundamental quantum gravity theories is notoriously difficult. In this paper, we aim to incorporate putative quantum corrections coming from loop quantum gravity in deriving modified dispersion relations for particles in a deformed Minkowski spacetime. We show how different choices of the Immirzi parameter can, in some cases, serendipitously lead to different outcomes for such modifications, depending on the quantization scheme chosen. This allows one to differentiate between these quantization choices via testable phenomenological predictions.

In this paper, we build upon the successes of the ultraviolet (UV) completion of the Starobinsky model of inflation. This involves an extension of the Einstein-Hilbert term by an infinite covariant derivative theory of gravity which is quadratic in curvature. It has been shown that such a theory can potentially resolve the cosmological singularity for a flat, homogeneous and isotropic geometry, and now it can also provide a successful cosmological inflation model, which in the infrared regime matches all the predictions of the Starobinsky model of inflation. The aim of this paper is to show that the tensor-to-scalar ratio is modified by the scale of nonlocality, and in general a wider range of tensor-to-scalar ratios can be obtained in this class of model, which can put a lower bound on the scale of nonlocality for the first time as large as the $\mathcal{O}(10^{14})\mathrm{GeV}$.

We propose and construct a two-parameter perturbative expansion around a Friedmann-Lemaître-Robertson-Walker geometry that can be used to model high-order gravitational effects in the presence of nonlinear structure. This framework reduces to the weak-field and slow-motion post-Newtonian treatment of gravity in the appropriate limits, but also includes the low-amplitude large-scale fluctuations that are important for cosmological modeling. We derive a set of field equations that can be applied to the late Universe, where nonlinear structure exists on supercluster scales, and perform a detailed investigation of the associated gauge problem. This allows us to identify a consistent set of perturbed quantities in both the gravitational and matter sectors, and to construct a set of gauge-invariant quantities that correspond to each of them. The field equations, written in terms of these quantities, take on a relatively simple form, and allow the effects of small-scale structure on the large-scale properties of the Universe to be clearly identified. We find that inhomogeneous structures source the global expansion, that there exist new field equations at new orders, and that there is vector gravitational potential that is a hundred times larger than one might naively expect from cosmological perturbation theory. Finally, we expect our formalism to be of use for calculating relativistic effects in upcoming ultralarge-scale surveys, as the form of the gravitational coupling between small and large scales depends on the nonlinearity of Einstein’s equations, and occurs at what is normally thought of as first order in cosmological perturbations.

The $\gamma +\gamma \to J/\psi +c+\overline{c}$ inclusive process is an extremely important subprocess in $J/\psi$ production via photon-photon scattering, like at LEPII or various types of future electron-positron colliders. In this work we perform the next-to-leading order (NLO) QCD corrections to this process in the framework of nonrelativistic QCD (NRQCD) factorization formalism, the first NLO calculation for two projectiles to the 3-body quarkonium inclusive production process. By setting the center-of-mass energy at LEPII, the $\sqrt{s}=197\mathrm{GeV}$, we conduct analyses of the $p_t^2$ distribution and total cross section of this process at the NLO accuracy. It turns out that the total cross section is moderately enhanced by the NLO correction with a $K$ factor of about 1.46, and hence the predicted $J/\psi$ inclusive productivity is increased while the DELPHI data still overshoot the theoretical prediction. At the future Circular Electron-Positron Collider, the NLO corrections are found to be more significant, with a $K$ factor of about 1.76.

We consider inflation within a model framework where the Higgs boson arises as a pseudo-Goldstone boson associated with the breaking of a global symmetry at a scale significantly larger than the electroweak one. We show that in such a model the scalar self-couplings can be parametrically suppressed and, consequently, the nonminimal couplings to gravity can be of order one or less, while the inflationary predictions of the model remain compatible with the precision cosmological observations. Furthermore, in the model we study, the existence of the electroweak scale is entirely due to the inflaton field. Our model therefore suggests that inflation and low energy particle phenomenology may be more entwined than assumed so far.

Semilocal and electroweak strings are well known to be unstable against unwinding by the condensation of the second Higgs component in their cores. A large class of current models of dark matter contains dark scalar fields coupled to the Higgs sector of the Standard Model (Higgs portal) and/or dark U(1) gauge fields. It is shown that Higgs-portal-type couplings and a gauge kinetic mixing term of the dark U(1) gauge field have a significant stabilizing effect on semilocal strings in the “visible” sector.

At the tail of its velocity distribution, cold dark matter (DM) can annihilate at finite temperature to states heavier than itself. We explore the possibility that DM freeze-out is dictated by these “forbidden annihilations” at the electroweak scale. Demanding that annihilation products be Standard Model particles, we find that for the forbidden mechanism to primarily set the DM relic abundance, DM must couple predominantly, if not solely, to top quarks. This can be arranged by invoking a nontrivial flavor structure such as minimal flavor violation. We avail two avenues to achieve the correct thermal cross section, requiring a mediator exchanged in the $s$- or $t$-channel. These simplified models submit easily to direct detection and collider searches, and necessarily hide from indirect detection signals. Viable supersymmetric spectra involving the forbidden mechanism may be found if combined with coannihilation.