Models beyond the Standard Model have been proposed to simultaneously solve the problems of naturalness and neutrino mass, in which heavy Majorana neutrinos and vectorlike top partners are usually predicted. A new decay channel of the top partner mediated by the heavy Majorana neutrino can thus appear: $T\to b{W}^{+}\to b{\ell }^{+}{\ell }^{+}q\overline{q^{\prime }}$. We study in this paper the observability of this decay process through single production of the top partner at the 14 TeV LHC: $pp\to T/\overline{T}+\text{jets}\to b/\overline{b}+{\mu }^{\pm }{\mu }^{\pm }+\text{jets}$. $2\sigma$ exclusion bounds on the top partner mass and mixing parameters are given by Monte-Carlo simulation, which surpass those from the search through vectorlike top partners pair production in the mass range of $m_T>1.3\mathrm{TeV}$.

We calculate the step-scaling function, the lattice analog of the renormalization group $\beta$-function, for an SU(3) gauge theory with ten fundamental flavors. We present a detailed analysis including the study of systematic effects of our extensive data set generated with ten dynamical flavors using the Symanzik gauge action and three times stout smeared Möbius domain wall fermions. Using up to ${32}^4$ volumes, we calculate renormalized couplings for different gradient flow schemes and determine the step-scaling $\beta$ function for a scale change $s=2$ on up to five different lattice volume pairs. In an accompanying paper we discuss that gradient flow can promote lattice dislocations to instantonlike objects, introducing nonperturbative lattice artifacts to the step-scaling function. Motivated by the observation that Wilson flow sufficiently suppresses these artifacts, we choose Wilson flow with the Symanzik operator as our preferred analysis. We study systematic effects by calculating the step-scaling function based on alternative flows (Zeuthen or Symanzik), alternative operators (Wilson plaquette, clover), and also explore the effects of the perturbative tree-level improvement. Further we investigate the effects due to the finite value of $L_s$.

MINERvA reports inclusive charged-current cross sections for muon neutrinos on hydrocarbon in the NuMI beamline. We measured the double-differential cross section in terms of the longitudinal and transverse muon momenta, as well as the single-differential cross sections in those variables. The data used in this analysis correspond to an exposure of $3.34\times {10}^{20}$ protons on target with a peak neutrino energy of approximately 3.5 GeV. Measurements are compared to the GENIE, NuWro and GiBUU neutrino cross-section predictions, as well as a version of GENIE modified to produce better agreement with prior exclusive MINERvA measurements. None of the models or variants were able to successfully reproduce the data across the entire phase space, which includes areas dominated by each interaction channel.

Horizons of black branes have an associated entropy current with non-negative divergence. We compute this divergence in a late-time transseries expansion for an inhomogeneous system evolving toward a maximally symmetric asymptotically anti–de Sitter black brane. The horizon area equilibrates on half the time scale set by the dominant quasinormal mode and we find a simple analytic expression for this evolution purely in terms of the background and the quasinormal mode frequencies. This computation does not require a gradient expansion and is thus nonperturbative in momenta. We generalize this to include scalar and gauge field matter in any number of dimensions. Restricting to homogeneous evolution we match and prove earlier numerical work showing that the apparent horizon entropy saturates the area theorem, in that its time derivative periodically vanishes. The same is true for spherically symmetric evolution toward the Schwarzschild black hole.

We study the vacuum polarization of a massive scalar field $\varphi$ with arbitrary coupling to gravity in pointlike global monopole spacetime. Using Schwinger-DeWitt proper time formalism, we calculate the vacuum expectation value $⟨{\varphi }^2⟩$, when the Compton length of the quantum field is much less than the characteristic radius of the curvature of the background geometry, and we can ignore nonlocal contributions. Explicit analytic expressions are obtained for a general curvature coupling parameter, and specified to the more physical cases of minimal and conformal coupling. Comparing the leading term of $⟨{\varphi }^2⟩$, proportional to the coincident limit of the Hadamard-DeWitt coefficient $a_2$, with higher order terms that include the coincidence limits of coefficients up to $a_5$, we conclude that the next to leading approximation needs to be used to give a more precise description of vacuum polarization effects in this structures. We also find the trace of the renormalized stress energy tensor for the quantized field in the leading approximation, using the existing relationship between this magnitude, the trace anomaly, and the field fluctuation.

The use of modern effective field theory techniques has sparked significant developments in many areas of physics, including the study of gravity. Case in point, such techniques have recently been used to show that binary black holes can amplify incident, low-frequency radiation due to an interplay between absorption at the horizons and momentum transfer in the bulk of the spacetime. In this paper, we further examine the consequences of this superradiant mechanism on the dynamics of an ambient scalar field by taking the binary’s long-range gravitational potential into account at the nonperturbative level. Doing so allows us to capture the formation of scalar clouds that are gravitationally bound to the binary. If the scalar is light enough, the cloud can be sufficiently diffuse (i.e., dilute while having considerable spatial extent) that it engulfs the binary as a whole. Its subsequent evolution exhibits an immensely rich phenomenology, which includes exponential growth, beating patterns, and the upscattering of bound states into scalar waves. While we find that these effects have negligible influence on the binary’s inspiral in the regime wherein our approximations are valid, they offer new, analytic insight into how binary black holes interact with external perturbations. They may also provide useful, qualitative intuition for interpreting the results from future numerical simulations of these complex systems.

We construct a model for the angular power spectrum of the instrumental noise in interferometer networks mapping gravitational wave backgrounds (GWBs) as a function of detector noise properties, network configuration, and scan strategy. We use the model to calculate the noise power spectrum for current and future ground-based experiments, as well as for planned space missions. We present our results in a language similar to that used in cosmic microwave background and intensity mapping experiments, and connect the formalism with the sensitivity curves that are common lore in GWB analyses.

In the present article, we study the orbital resonance that corresponds to an extended object approximated up to the dipole order term in Kerr spacetime. We start with the Mathisson-Papapetrou equations under the linear spin approximation and primarily concentrate on two particular events: first, when the orbits are nearly circular and executing a small oscillation about the equatorial plane and second, a generic trajectory confined on the equatorial plane. While in the first case, all three fundamental frequencies, namely, radial ${\mathrm{\Omega }}_r$, angular ${\mathrm{\Omega }}_{\theta }$, and azimuthal ${\mathrm{\Omega }}_{\varphi }$ can be commensurate with each other and give rise to the resonance phenomenon, the later is only accompanied with the resonance between ${\mathrm{\Omega }}_r$ and ${\mathrm{\Omega }}_{\varphi }$ as we set $\theta =\pi /2$. We provide a detailed derivation in locating the prograde resonant orbits in either of these cases and also study the role played by the spin of the black hole. The implications related to spin-spin interactions between the object and black hole are also demonstrated.

We find new static, spherically symmetric, and asymptotically flat vacuum solutions without horizon in Starobinsky’s quadratic $f(R)$ gravity. We systematically classify these solutions by an asymptotic analysis around the origin and find seven different integer Frobenius families. We numerically solve the exact equations of motion by a double-shooting method and specify boundary conditions by matching the numerical solution to the analytic solution of the linearized field equations in the weak field regime. We find that all integer Frobenius families can be connected to asymptotically flat solutions and trace out lines in the parameter space, allowing to ultimately relate all free parameters to the total mass at infinity.

We present the $d+1$ formulation of Einstein-scalar-Gauss-Bonnet (ESGB) theories in dimension $D=d+1$ and for arbitrary (spacelike or timelike) spacetime foliations. We first build an action which generalizes those of Gibbons-Hawking-York and Myers to ESGB theories, showing that they can be described by a Dirichlet variational principle. We then generalize the Arnowitt-Deser-Misner (ADM) Lagrangian and Hamiltonian to ESGB theories, as well as the resulting $d+1$ decomposition of the equations of motion. Unlike general relativity, the canonical momenta of ESGB theories are nonlinear in the extrinsic curvature. This has two main implications: (i) the ADM Hamiltonian is generically multivalued, and the associated Hamiltonian evolution is not predictable; (ii) the “$d+1$” equations of motion are quasilinear, and they may break down in strongly curved, highly dynamical regimes. Our results should be useful to guide future developments of numerical relativity for ESGB gravity in the nonperturbative regime.

Teleparallel gravity (TG) describes gravitation as a torsional- rather than curvature-based effect. As in curvature-based constructions of gravity, several different formulations can be proposed, one of which is the teleparallel equivalent of general relativity (TEGR) which is dynamically equivalent to GR. In this work, we explore the evolution of a spatially homogeneous collapsing stellar body in the context of two important modifications to TEGR, namely $f(T)$ gravity, which is the TG analog of $f(R)$ gravity, and a nonminimal coupling with a scalar field which has become popular in TG for its effects in cosmology. We explore the role of geodesic deviation to study the congruence of nearby particles in lieu of the Raychaudhuri equation. We find $f(T)$ models that satisfy the null energy condition and describe interesting collapse profiles. In the case of a nonminimally coupled scalar field, we also find potential collapse models with intriguing scalar field evolution profiles.

In this paper, we explore momentum space approach to computing scalar amplitudes in anti–de Sitter (AdS) space. We show that the algorithm derived by Arkani-Hamed, Benincasa, and Postnikov for cosmological wave functions can be straightforwardly adopted for AdS transition amplitudes in momentum space, allowing one to bypass bulk point integrations. We demonstrate the utility of this approach in AdS by presenting several explicit results both at tree and loop level.

We have investigated the problem of traversability of wormholes in the framework of quantum improvement of gravity theory arising from functional renormalization group methods to describe the asymptotic safe quantum gravity. We have shown that improved pseudospherical wormholes could be traversable with nonexotic matter, while spherical ones could not. This is done within a specific model of improvement.

In this paper we extend the quasitopological electromagnetism, recently introduced by H.-S. Liu et al. [arXiv:1907.10876], to arbitrary dimensions by introducing a fundamental $p$-form field. This allows us to construct new dyonic black hole solutions in odd dimensions, as well as regular $D$-dimensional black holes and solitons. The three-dimensional system consists of a Maxwell field interacting with a scalar field, leading to a deformation of the Bañados-Teitelboim-Zanelli black hole. We present the general formulas defining the black hole solutions in arbitrary dimensions in Lovelock theory and explore the thermal properties of the asymptotically anti–de Sitter black holes in the gravitational framework of general relativity. In five dimensions, the latter black holes possess a rich phase space structure in the canonical ensemble, giving rise to as many as five different black hole phases at a fixed temperature, for a given range of the parameters.

We present a frequency-domain reduced-order model (ROM) for the aligned-spin effective-one-body model for binary black holes (BBHs) seobnrv4hm that includes the spherical-harmonics modes $(\ell ,|m|)=(2,1),(3,3),(4,4),(5,5)$ beyond the dominant $(\ell ,|m|)=(2,2)$ mode. These higher modes are crucial to accurately represent the waveform emitted from asymmetric BBHs. We discuss a decomposition of the waveform, extending other methods in the literature, that allows us to accurately and efficiently capture the morphology of higher mode waveforms. We show that the ROM is very accurate with median (maximum) values of the unfaithfulness against seobnrv4hm lower than $0.001\%(0.03\%)$ for total masses in $[2.8,100]M_{\odot }$. For a total mass of $M=300M_{\odot }$, the median (maximum) value of the unfaithfulness increases up to $0.004\%(0.17\%)$. This is still at least an order of magnitude lower than the estimated accuracy of seobnrv4hm compared to numerical relativity simulations. The ROM is 2 orders of magnitude faster in generating a waveform compared to seobnrv4hm. Data analysis applications typically require $\mathcal{O}({10}^6–{10}^8)$ waveform evaluations for which seobnrv4hm is in general too slow. The ROM is therefore crucial to allow the seobnrv4hm waveform to be used in searches and Bayesian parameter inference. We present a targeted parameter estimation study that shows the improvements in measuring binary parameters when using waveforms that includes higher modes and compare against three other waveform models.

We study spherically symmetric magnetically charged generic singular black hole solutions of general relativity coupled to nonlinear electrodynamics. For characteristic values of the generic spacetime parameters and the parameter characterizing the ratio of the gravitational and electromagnetic forces acting on an electrically charged particle we study the circular orbits and related epicyclic motion and its frequencies. We demonstrate that the equatorial circular orbits are forbidden in such situations, but off-equatorial circular orbits are possible. We give dependence of the stable circular orbit on the spacetime parameters and intensity of the electromagnetic interaction of the charged particles with magnetically charged black holes. We study the possible resonance phenomena of the epicyclic frequencies and the orbital frequency of the electrically charged particles in order to fit the data of the twin high-frequency quasiperiodic oscillations of x rays observed in microquasars. Moreover, the dynamics of magnetized particles around the magnetically charged generic black hole have also been explored and it is shown that as increasing magnetic charge and magnetic moment parameters, the innermost stable circular orbit (ISCO) radius decreases and disappears at some value of the magnetic moment parameter, inversely proportional to the magnetic charge of black hole. As an astrophysical application we treated the magnetar PSR J1745–2900 orbiting around Sagittarius (Sgr) A* as a magnetized particle and showed that the magnetic charge of black hole can mimic black hole spin up to $a/M=0.865694$ at $\nu =2$, and the spin parameter can mimic the magnetic charge parameter up to $q/M=0.578575$ at $\nu =1$, providing exactly the same value of the ISCO radius. Finally, we predict that no magnetar with the surface magnetic field of the order of ${10}^{14}–10^{15}\mathrm{G}$ can follow stable orbits, but it is possible to observe ordinary neutron stars as recycled radio pulsars in the close environment of Sgr A*.

We present a new approach to model the gravitational dynamics of large-scale structures. Instead of solving the equations of motion up to a finite perturbative order or building phenomenological models, we follow the evolution of the probability distribution of the displacement and velocity fields within an approximation subspace. Keeping the exact equations of motion with their full nonlinearity, this provides a nonperturbative scheme that goes beyond shell crossing. Focusing on the simplest case of a curl-free Gaussian Ansatz for the displacement and velocity fields, we find that truncations of the power spectra on nonlinear scales directly arise from the equations of motion. This leads to a truncated Zeldovich approximation for the density power spectrum, but with a truncation that is not set a priori and with different power spectra for the displacement and velocity fields. The positivity of their autopower spectra also follows from the equations of motion. Although the density power spectrum is only recovered up to a smooth drift on baryon acoustic oscillation (BAO) scales, the predicted density correlation function agrees with numerical simulations within 2% from BAO scales down to $7h^{-1}\mathrm{Mpc}$ at $z\ge 0.35$, without any free parameter. Thus, this parameter-free extension of the Zeldovich approximation is not competitive with other schemes for the power spectrum, but it provides a good prediction for the correlation function. However, the improvement over the standard Zeldovich approximation remains rather modest. This means that including non-Gaussianities will be essential to significantly improve analytical predictions within this general framework.

We study the dynamics of a spectator Higgs field which stochastically evolves during inflation onto near-critical trajectories on the edge of a runaway instability. We show that its fluctuations do not produce primordial black holes in sufficient abundance to be the dark matter, nor do they produce significant second-order gravitational waves. First we show that the Higgs produces larger fluctuations on cosmic microwave background scales than on primordial black hole (PBH) scales, itself a no go for a viable PBH scenario. Then we track the superhorizon perturbations nonlinearly through reheating using the $\delta N$ formalism to show that they are not converted to large curvature fluctuations. Our conclusions hold regardless of any fine-tuning of the Higgs field for both the Standard Model Higgs and Higgs potentials modified to prevent unbounded runaway.

We present a critical assessment of the SN1987A supernova cooling bound on axions and other light particles. Core collapse simulations used in the literature to substantiate the bound omitted from the calculation the envelope exterior to the proto-neutron star (PNS). As a result, the only source of neutrinos in these simulations was, by construction, a cooling PNS. We show that if the canonical delayed neutrino mechanism failed to explode SN1987A, and if the precollapse star was rotating, then an accretion disk would form that could explain the late-time ($t\gtrsim 5\sec$) neutrino events. Such accretion disk would be a natural feature if SN1987A was a collapse-induced thermonuclear explosion. Axions do not cool the disk and do not affect its neutrino output, provided the disk is optically thin to neutrinos, as it naturally is. These considerations cast doubt on the supernova cooling bound.