One of the leading mechanisms powering relativistic black hole jets is the Blandford-Znajek process. Inspired by its success we construct energy extracting models for black holes in five spacetime dimensions. Here, we find solutions to the force-free electrodynamic equations representing plasma magnetospheres for slowly rotating Myers-Perry black holes. Both energy and angular momentum fluxes are computed for these solutions realizing power extraction from black holes in higher dimensions. Comparisons of the main features of the five-dimensional Blandford-Znajek models with lower four-dimensional counterparts are discussed.

We show that the observed angular diameter of the shadow of the ultracompact object Sgr A*, favors the existence of an extra spatial dimension. This holds irrespective of the nature of the ultracompact object, i.e., whether it is a wormhole or a black hole mimicker, but with the common feature that both of them have an extra dimensional origin. This result holds true for the mass and the distance measurements of Sgr A* using both Keck and the Gravity collaborations and whether we use the observed image or, the observed shadow diameter. In particular, the central value of the observed shadow or the observed image diameter predicts nonzero hairs inherited from the extra dimensions.

In this work, we introduce a class of extended minimal theories of massive gravity, without requiring a priori that the theory should admit the same homogeneous and isotropic cosmological solutions as the de Rham-Gabadadze-Tolley massive gravity. The theory is constructed as to have only two degrees of freedom in the gravity sector. In order to perform this step we first introduce a precursor theory endowed with a general graviton mass term, to which, at the level of the Hamiltonian, we add two extra constraints as to remove the unwanted degrees of freedom, which otherwise would typically lead to ghosts and/or instabilities. On analyzing the number of independent constraints and the properties of tensor mode perturbations, we see that the gravitational waves are the only propagating gravitational degrees of freedom which do acquire a nontrivial mass, as expected. In order to understand how the effective gravitational force works for this theory we then investigate cosmological scalar perturbations in the presence of a pressureless fluid. We then restrict the whole class of models by imposing the following conditions at all times: (1) it is possible to define an effective gravitational constant, $G_{\mathrm{eff}}$; (2) the value $G_{\mathrm{eff}}/G_N$ is always finite but not always equal to unity (as to allow some nontrivial modifications of gravity, besides the massive tensorial modes); and (3) the square of mass of the graviton is always positive. These constraints automatically make also the ISW-effect contributions finite at all times. Finally we focus on a simple subclass of such theories, and show they already can give a rich and interesting phenomenology.

We show how the recently developed string-inspired, projectively invariant gravitational model Thomas-Whitehead gravity (TW gravity) naturally gives rise to a field acting as the inflaton. In the formulation of TW gravity, a field ${\mathcal{D}}_{ab}$ is introduced into the projective connection components and is related to a rank-two tensor field ${\mathcal{P}}_{ab}$. Through the dynamical action of TW gravity, in terms of projective curvature, the tensor field ${\mathcal{P}}_{ab}$ acquires dynamics. By decomposing ${\mathcal{P}}_{ab}$ into its trace and traceless degrees of freedom, and choosing the connection to be Levi-Civita, we demonstrate that TW gravity contains a nonminimally coupled scalar field with a specific potential. Considering only the trace degrees of freedom, we demonstrate that the scalar field acts as an inflaton in the slow-roll approximation. We find a range of values for the parameters introduced by TW gravity that fit the experimental constraints of the most recent cosmological data.

We study the null and timelike geodesics of light and the neutral particles, respectively, in the exterior of Kerr-Newman black holes. The geodesic equations are known to be written as a set of first-order differential equations in Mino time from which the angular and radial potentials can be defined. We classify the roots for both potentials, and mainly focus on those of the radial potential with an emphasis on the effect from the charge of the black holes. We then obtain the solutions of the trajectories in terms of the elliptical integrals and the Jacobian elliptic functions for both null and timelike geodesics, which are manifestly real functions of the Mino time that the initial conditions can be explicitly specified. We also describe the details of how to reduce those solutions into the cases of the spherical orbits. The effect of the black hole’s charge decreases the radii of the spherical motion of the light and the particle for both direct and retrograde motions. In particular, we focus on the light/particle boomerang of the spherical orbits due to the frame dragging from the back hole’s spin with the effect from the charge of the black hole. To sustain the change of the azimuthal angle of the light rays, say for example $\mathrm{\Delta }\varphi =\pi$ during the whole trip, the presence of the black hole’s charge decreases the radius of the orbit and consequently reduces the needed values of the black hole’s spin. As for the particle boomerang, the particle’s inertia renders smaller change of the angle $\mathrm{\Delta }\varphi$ as compared with the light boomerang. Moreover, the black hole’s charge also results in the smaller angle change $\mathrm{\Delta }\varphi$ of the particle than that in the Kerr case. The implications of the obtained results to observations are discussed.

Does circumventing the curvature singularity of the Kerr black hole affect the timescale of the scalar cloud formation around it? By definition, the scalar cloud, forms a gravitational atom with hydrogen-like bound states, lying on the threshold of a massive scalar field’s superradiant instability regime (time-growing quasibound states) and beyond (time-decaying quasibound states). By taking a novel type of rotating hollow regular black hole proposed by Simpson and Visser which unlike its standard rivals has an asymptotically Minkowski core, we address this question. The metric has a minimal extension relative to the standard Kerr, originating from a single regularization parameter $\ell$, with length dimension. We show with the inclusion of the regularization length scale $\ell$ into the Kerr spacetime, without affecting the standard superradiant instability regime, the timescale of scalar cloud formation gets shorter. Since the scalar cloud after its formation, via energy dissipation, can play the role of a continuum source for gravitational waves, such a reduction in the instability growth time improves the phenomenological detection prospects of new physics because the shorter the time, the more astrophysically important.

Inflation models based on scalar-tensor theories of gravity are formulated in the Jordan frame, but are most often analyzed in the Einstein frame. The transformation between the frames is not always desirable. In this work, we formulate slow-roll conditions in the Jordan frame. This is achieved by comparing different background quantities and approximations on the same spatial slice in both frames. We use these approximations to derive simple equations that can be applied to compute inflation model observables in terms of Jordan frame quantities only. Finally, we apply some of the results to analyze generalized induced gravity models and compare them with the latest observations.

We continue our exploration of the wiggly generalization of the velocity-dependent one scale model for cosmic strings, through the study of its allowed asymptotic scaling solutions. We extend the work of a previous paper [A. R. R. Almeida and C. J. A. P. Martins, Phys. Rev. D 104, 043524 (2021).] by considering the more comprehensive case of a time-varying coarse-graining scale for the string wiggles. The modeling of the evolution of the network therefore relies on three main mechanisms: Hubble expansion, energy transfer mechanisms (e.g., the production of loops and wiggles) and the choice of the scale at which wiggles are coarse-grained. We analyze the role of each of them on the overall behavior of the network, and thus in the allowed scaling solutions. In Minkowski space, we find that linear scaling, previously observed in numerical simulations without expansion, is not possible with a changing averaging scale. For expanding universes, we find that the three broad classes of scaling solutions—with the wiggliness disappearing, reaching scaling, or growing—still exist but are differently impacted by the time evolution of the coarse-graining scale. Nambu-Goto type solutions (without wiggles) are unaffected, growing wiggliness solutions are trivially generalized, while for solutions where wiggliness reaches scaling the expansion rate for which the solution exists is decreased with respect to the one for a fixed coarse-graining scale. Finally, we also show that the inclusion of a time-varying coarse-graining scale allows, in principle, for additional scaling solutions which, although mathematically valid, are not physical. Overall, our mapping of the landscape of the allowed scaling solutions of the wiggly velocity-dependent one scale model paves the way for the detailed testing of the model, to be done by forthcoming high-resolution field theory and Nambu-Goto simulations.

Cold dark matter subhalos are expected to populate galaxies in numbers. If dark matter self-annihilates, these objects turn into prime targets for indirect searches, in particular with gamma-ray telescopes. Incidentally, the Fermi-LAT catalog already contains many unidentified sources that might be associated with subhalos. In this paper, we determine the probability for subhalos to be identified as gamma-ray pointlike sources from their predicted distribution properties. We use a semi-analytical model for the Galactic subhalo population, which, in contrast to cosmological simulations, can be made fully consistent with current kinematic constraints in the Milky Way and has no resolution limit. The model incorporates tidal stripping effects from a realistic distribution of baryons in the Milky Way. The same baryonic distribution contributes a diffuse gamma-ray foreground which adds up to that, often neglected in subhalo searches, generated by the smooth dark matter and the unresolved subhalos. This configuration implies a correlation between pointlike subhalo signals and diffuse background. Based on this semi-analytical modeling, we generate mock gamma-ray data assuming an idealized telescope resembling Fermi-LAT and perform a likelihood analysis to estimate the current and future sensitivity to subhalos in the relevant parameter space. We find a number of detectable subhalos of order $\mathcal{O}(<1)$ for optimistic model parameters and a WIMP mass of 100 GeV, maximized for a cored host halo. This barely provides support to the current interpretation of several Fermi unidentified sources as subhalos. We also find it more likely to detect the smooth Galactic halo itself before subhalos, should dark matter in the GeV-TeV mass range self-annihilate through $s$-wave processes.

Low internal friction coatings are key components of advanced technologies such as optical atomic clocks and high-finesse optical cavities and often lie at the forefront of the most advanced experiments in physics. Notably, increasing the sensitivity of gravitational-wave detectors depends in a very large part on developing new coatings, which entails developing more suitable methods and models to investigate their loss angle. In fact, the most sensitive region of the detection band in such detectors is limited by the coating thermal noise, which is related to the loss angle of the coating. Until now, models which describe only ideal physical properties have been adopted, wondering about the use of one or more loss angles to describe the mechanical properties of coatings. Here we show the presence of a systematic error ascribed to inhomogeneity of the sample at its edges in measuring the coating loss angle. We present a model for disk-shaped resonators, largely used in loss angle measurements, and we compare the theory with measurements showing how this systematic error impacts on the accuracy with which the loss model parameters are known.

A technique of large-charge expansion provides a novel opportunity for calculation of critical dimensions of operators ${\varphi }^Q$ with fixed charge $Q$. In the small-coupling regime the polynomial structure of the anomalous dimensions can be fixed from a number of direct perturbative calculations for a fixed $Q$. At the six-loop level, one needs to include new diagrams that correspond to operators with five or more legs. The latter never appeared before in scalar-theory calculations. Here we show how to compute the anomalous dimension of the operator ${\varphi }^{Q=5}$ at the six-loop order. In combination with results for operators with $Q<5$, which are extracted from the six-loop beta functions for general scalar theory, and with predictions from the large-charge expansion, our calculation allows us to derive the answer for general-$Q$ anomalous dimensions. At the critical point resummation in three dimensions enables us to compare the critical exponents with results of Monte Carlo simulations and large-$N$ predictions.

We analyze the classically scale-invariant $B-L$ model in the context of resonant leptogenesis with the recently proposed mass-gain mechanism. The $B-L$ symmetry breaking in this scenario is associated with a strong first-order phase transition that gives rise to detectable gravitational waves (GWs) via bubble collisions. The same $B-L$ symmetry breaking also gives Majorana mass to right-handed neutrinos inside the bubbles, and their out-of-equilibrium decays can produce the observed baryon asymmetry of the Universe via leptogenesis. We show that the current LIGO-VIRGO limit on stochastic GW background already excludes part of the $B-L$ parameter space, complementary to the collider searches for heavy $Z^{\prime }$ resonances. Moreover, future GW experiments like Einstein Telescope and Cosmic Explorer can effectively probe the parameter space of leptogenesis over a wide range of the $B-L$ symmetry-breaking scales and gauge coupling values.

We study the direct radiation excited by oscillating axion (or axionlike particle) dark matter in a homogeneous magnetic field, as well as its detection scheme. We concretely derive the analytical expression of the axion-induced radiated power for a cylindrical uniform magnetic field. In the long wave limit, the radiation power is proportional to the square of the B-field volume and the axion mass $m_a$; however, it oscillates as it approaches the short wave limit, and the peak powers are proportional to the side area of the cylindrical magnetic field and $m_a^{-2}$. The maximum power is located at mass $m_a\sim \frac{3\pi }{4R}$ for fixed radius $R$. Based on this characteristic of the power, we discuss a scheme to detect the axions in the mass range $1–{10}^4\mathrm{neV}$, where four detectors of different bandwidths surround the B-field. The expected sensitivity for $m_a\lesssim 1\mu \mathrm{eV}$ under typical parameter values can far exceed the existing constraints.

In this work, we obtain the leading subeikonal corrections to the jet momentum broadening distribution in a QCD medium arising from the transverse flow of the matter. We first derive the single-particle propagator of a highly energetic parton resumming its multiple interactions with the homogeneous flowing matter, explicitly keeping the leading subeikonal flow terms. Then, we use this propagator to obtain the jet broadening distribution and its leading moments. We show that this distribution becomes anisotropic in the presence of transverse flow, since its odd moments are generally nonzero and proportional to the transverse velocity of the medium. Finally, we evaluate several odd moments, which we compare to the corresponding results at first order in opacity, showing that accounting for multiple in-medium scatterings is essential to describe some observables in dense nuclear matter.

The semileptonic ${\mathrm{\Omega }}_c^0\to {\mathrm{\Omega }}^{-}l\nu$ and nonleptonic ${\mathrm{\Omega }}_c^0\to {\mathrm{\Omega }}^{-}{\pi }^{+}$, ${\mathrm{\Omega }}_c^0\to {\mathrm{\Omega }}^{-}{\rho }^{+}$ decays of the charmed ${\mathrm{\Omega }}_c$ baryon are studied within the light cone sum rules. The form factors responsible for ${\mathrm{\Omega }}_c\to \mathrm{\Omega }$ transitions are calculated using the distribution amplitudes of the ${\mathrm{\Omega }}_c$ baryon. With the obtained form factors, the branching ratios of ${\mathrm{\Omega }}_c^0\to {\mathrm{\Omega }}^{-}{l}^{+}{\nu }_l$, ${\mathrm{\Omega }}_c^0\to {\mathrm{\Omega }}^{-}{\pi }^{+}$, and ${\mathrm{\Omega }}_c^0\to {\mathrm{\Omega }}^{-}{\rho }^{+}$ decays are estimated. The results are compared with Belle data as well as the findings of other approaches.

A search for a massless dark photon ${\gamma }^{\prime }$ is conducted using $4.5{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ collision data collected at center-of-mass energies between 4.600 and 4.699 GeV with the BESIII detector at BEPCII. No significant signal is observed, and the upper limit on the branching fraction $\mathcal{B}({\mathrm{\Lambda }}_c^{+}\to p{\gamma }^{\prime })$ is determined to be $8.0\times {10}^{-5}$ at 90% confidence level.

Using 448 million $\psi (2S)$ events, the spin-singlet $P$-wave charmonium state $h_c(1{}^1{P}_1)$ is studied via the $\psi (2S)\to {\pi }^0{h}_c$ decay followed by the $h_c\to \gamma {\eta }_c$ transition. The branching fractions are measured to be ${\mathcal{B}}_{\text{Inc}}(\psi (2S)\to {\pi }^0{h}_c)\times {\mathcal{B}}_{\text{Tag}}(h_c\to \gamma {\eta }_c)=(4.22_{-0.26}^{+0.27}\pm 0.19)\times {10}^{-4}$, ${\mathcal{B}}_{\text{Inc}}(\psi (2S)\to {\pi }^0{h}_c)=(7.32\pm 0.34\pm 0.41)\times {10}^{-4}$, and ${\mathcal{B}}_{\text{Tag}}(h_c\to \gamma {\eta }_c)=(57.66_{-3.50}^{+3.62}\pm 0.58)\%$, where the uncertainties are statistical and systematic, respectively. The $h_c(1{}^1{P}_1)$ mass and width are determined to be $M=(3525.32\pm 0.06\pm 0.15)\mathrm{MeV}/{\mathrm{c}}^2$ and $\mathrm{\Gamma }=(0.78_{-0.24}^{+0.27}\pm 0.12)\mathrm{MeV}$. Using the center of gravity mass of the three ${\chi }_{cJ}(1^3{P}_J)$ mesons [$M(\mathrm{c}.\mathrm{o}.\mathrm{g}.)$], the $1P$ hyperfine mass splitting is estimated to be ${\mathrm{\Delta }}_{\mathrm{hyp}}=M(h_c)-M(\mathrm{c}.\mathrm{o}.\mathrm{g}.)=(0.03\pm 0.06\pm 0.15)\mathrm{MeV}/{\mathrm{c}}^2$, which is consistent with the expectation that the $1P$ hyperfine splitting is zero at the lowest order.

While the ten-dimensional type IIB supergravity action evaluated on ${\mathrm{AdS}}_5\times S^5$ solution vanishes, the five-dimensional effective action reconstructed from equations of motion using the $M^5\times S^5$ compactification ansatz is proportional to the ${\mathrm{AdS}}_5$ volume. The latter is consistent with the conformal anomaly interpretation in $\mathrm{AdS}/\mathrm{CFT}$ context. We show that this paradox can be resolved if, in the case of $M^5\times X^5$ topology, the ten-dimensional action contains an additional 5-form-dependent “topological” term $\int F_{5M}\wedge F_{5X}$. The presence of this term is suggested also by gauge-invariance considerations in the Pasti-Sorokin-Tonin formulation of type IIB supergravity action. We show that this term contributes to the ten-dimensional action evaluated on the D3-brane solution.

Bosonic field theories with self-interactions alongside gravity generally admit bound states known as solitons. Depending upon the spin nature of the field, they can even carry macroscopic intrinsic spin polarization. Focusing on the SU(2) case, we describe polarized solitons in non-Abelian theories with a heavy Higgs, which we refer to as “Yang-Mills stars.” Owing to both kinds of self-interactions, repulsive ones arising due to the Yang-Mills structure and attractive ones arising due to the Higgs exchange, we can have a diverse zoo of solitons. Depending upon various parameters of the theory, such as the mass of the Yang-Mills vector fields $m$, mass of the dark Higgs field $M_{\phi }$, and the gauge coupling constant $g$, these objects can be astrophysically large with varying size and mass, and they can carry large intrinsic spin and/or isospin giving rise to interesting phenomenological implications. Even for vector mass as large as $m\simeq 10\mathrm{eV}$, we can accommodate gauge couplings $g\lesssim {10}^{-4}-{10}^{-5}$, still evading Bullet Cluster constraints. For these parameters, there may exist cosmologically long-lived solitons having radii as large as $r_s\sim {10}^5{R}_{\odot }$ and masses $M_s\sim 10M_{\odot }$, carrying $M_s/m\sim {10}^{66}$ amounts of intrinsic spin and isospin polarization. As a subset of the space of soliton solutions in the SU(2) Higgs model, in the end we also explicitly discuss solitons in the Abelian Higgs model.

The main goal of this paper is to investigate one of the important astrophysical systems, namely Thick accretion disks, in the background of the spherically symmetric solution in Born-Infeld teleparallel gravity to examine observable predictions of the theory in the vicinity of black holes. Thus, the properties of the non-self-gravitating equilibrium surfaces characterizing the Thick accretion disks model are studied. In addition, we find an observational bound on the parameter of the model as $\lambda \gtrsim 140$. We show this analytical accretion disk model for different values of $\lambda$ and compare the result with the corresponding Schwarzschild solution in the general theory of relativity.