Using our extension of the quark potential model to hybrid mesons that fits well with the available lattice results, we now calculate the masses, radii, wave functions at the origin, leptonic and two-photon decay widths, and $E1$ and $M1$ radiative transitions for a significant number of bottomonium mesons. These mesons include both conventional and hybrid ones with radial and angular excitations. Our numerical solutions of the Schrödinger equation are related to QCD through the Born-Oppenheimer approach. Relativistic corrections in masses and decay widths are also calculated by applying the leading-order perturbation theory. The calculated results are compared with available experimental data and the theoretical results by other groups. We also identify the states of $\mathrm{\Upsilon }(10860)$, $\mathrm{\Upsilon }(11020)$, and $Y_b(10890)$ mesons by comparing their experimental masses and decay widths to our results.

We have calculated cross sections for the production of lepton pairs by a neutrino incident on a nucleus using both the equivalent photon approximation and deep-inelastic formalism. We find that production of mixed flavor lepton pairs can have production cross sections as high as 35 times those of the traditional ${\nu }_{\mu }\to {\nu }_{\mu }{\mu }^{+}{\mu }^{-}$ process. Rates are estimated for the SHiP and DUNE intensity frontier experiments. We find that multiple trident production modes, some of which have never been observed, represent observable signals over the lifetime of the detectors. Our estimates indicate that the SHiP Collaboration should be able to observe on the order of 300 trident events given $2\times {10}^{20}$ protons on target and that the DUNE Collaboration can expect approximately 250 trident events in their near detector given $3\times {10}^{22}$ protons on target. We also discuss possible applications of the neutrino trident data to be collected at SHiP and DUNE for Standard Model and beyond the Standard model physics.

We study the chiral ring of four-dimensional superconformal field theories obtained by wrapping M5-branes on a complex curve inside a Calabi–Yau threefold. We propose a field theoretic construction of all the theories found by Bah, Beem, Bobev and Wecht by introducing new building blocks and prove several $\mathcal{N}=1$ dualities featuring the latter. We match the central charges with those computed from the M5-brane anomaly polynomial, perform the counting of relevant operators and analyze unitarity bound violations. As a by-product, we compute the exact dimension of “heavy operators” obtained by wrapping an M2-brane on the complex curve.

We study the effective action for the massive vector field theory nonminimally coupled to external gravitational field. Such a theory is an interesting model both from the theoretical side and also due to the various phenomenological applications to cosmology and astrophysics. The present work pretends to initiate a systematic study of its properties at the quantum level, by exploring free massive vector coupled to an external symmetric second-rank tensor. Stueckelberg scalar field is used to restore the gauge invariance. After that, by using a special gauge fixing and nonlocal in external fields change of variables, we diagonalize the bilinear form of the action and develop a consistent procedure to study the effective action. As a result we derive a complete nonlinear structure of divergences of the effective action and discuss its properties.

We study here the precession of the spin of a test gyroscope attached to a stationary observer in the Kerr spacetime, specifically, to distinguish a naked singularity (NS) from a black hole (BH). It was shown recently that for gyros attached to static observers, their precession frequency became arbitrarily large in the limit of approach to the ergosurface. For gyros attached to stationary observers that move with nonzero angular velocity $\mathrm{\Omega }$, this divergence at the ergosurface can be avoided. Specifically, for such gyros, the precession frequencies diverge on the event horizon of a BH, but are finite and regular for a NS everywhere except at the singularity itself. Therefore a genuine detection of the event horizon becomes possible in this case. We also show that for a near-extremal NS ($1<a_{*}<1.1$), characteristic features appear in the radial profiles of the precession frequency, using which we can further distinguish a near-extremal NS from a BH, or even from a NS with larger angular momentum. We then investigate the Lense-Thirring (LT) precession or nodal plane precession frequency of the accretion disk around a BH and NS to show that clear distinctions exist for these configurations in terms of radial variation features. The LT precession in equatorial circular orbits increases on approaching a BH, whereas for NS it increases, attains a peak, and then decreases. Interestingly, for $a_{*}=1.089$, it decreases until it vanishes at a certain radius, and it acquires negative values for $a_{*}>1.089$ for a certain range of $r$. For $1<a_{*}<1.089$, a peak appears, but the LT frequency remains positive definite. There are important differences in accretion disk LT frequencies for a BH and a NS and since LT frequencies are intimately related to observed quasiperiodic oscillations, these features might allow us to determine whether a given rotating compact astrophysical object is a BH or a NS.

We study the intermediate inflation scenario in the context of $F(T)$ gravity, and we examine its viability by calculating the power spectrum of the primordial curvature perturbations and the corresponding spectral index. As we demonstrate, it is possible for the resulting spectral index to be compatible with the observational data and we investigate the parameter space in order to see when the compatibility with data is possible.

The field equation for a spin $1/2$ massive charged particle propagating in spacetimes that are the direct product of two-dimensional spaces is separated. Moreover, we use this result to attain the separability of the Dirac equation in some specific static black hole solutions whose horizons have topology $\mathbb{R}\times {\mathbb{S}}^2\times \cdots \times {\mathbb{S}}^2$.

The deflection angle of a light ray can be arbitrarily large near a light sphere. The time-symmetrical shape of light curves of a pair of light rays reflected by a light sphere of a lens object does not depend on the details of the lens object. We consider retrolensing light curves of sunlight with deflection angles $\pi$ and $3\pi$ by an Ellis wormhole, which is the simplest Morris-Thorne wormhole. If an Ellis wormhole with a throat parameter $a={10}^{11}\mathrm{km}$ is 100 pc away from an observer and if the Ellis wormhole, the observer, and the Sun are aligned perfectly in this order, the apparent magnitudes of a pair of light rays with deflection angles $\pi$ and $3\pi$ become 11 and 18, respectively. The two pairs of light rays make a superposed light curve with two separable peaks and they break down time symmetry of a retrolensing light curve. The observation of the two separated peaks of the light curves gives us information on the details of the lens object. If the observer can also separate the pair of the images with the deflection angle $\pi$ into a double image, he or she can say whether the retrolensing is caused by an Ellis wormhole or a Schwarzschild black hole.

In general relativity (GR), the metric tensor of spacetime is essential since it represents the gravitational potential. In other gauge theories (such as electromagnetism), the so-called premetric approach succeeds in separating the purely topological field equation from the metric-dependent constitutive law. We show here that GR allows for a premetric formulation, too. For this purpose, we apply the teleparallel approach of gravity, which represents GR as a gauge theory based on the translation group. We formulate the metric-free topological field equation and a general linear constitutive law between the basic field variables. The requirement of local Lorentz invariance turns the model into a full equivalent of GR. Our approach opens a way for a natural extension of GR to diverse geometrical structures of spacetime.

We use state-of-the-art measurements of the galaxy luminosity function (LF) at $z=6$, 7, and 8 to derive constraints on warm dark matter (WDM), late-forming dark matter, and ultralight axion dark matter models alternative to the cold dark matter (CDM) paradigm. To this purpose, we have run a suite of high-resolution $N$-body simulations to accurately characterize the low-mass end of the halo mass function and derive dark matter (DM) model predictions of the high-z luminosity function. In order to convert halo masses into UV magnitudes, we introduce an empirical approach based on halo abundance matching, which allows us to model the LF in terms of the amplitude and scatter of the ensemble average star formation rate halo mass relation, $⟨\mathrm{SFR}({\mathrm{M}}_{\mathrm{h}},z)⟩$, of each DM model. We find that, independent of the DM scenario, the average SFR at fixed halo mass increases from $z=6$ to 8, while the scatter remains constant. At halo mass ${\mathrm{M}}_{\mathrm{h}}\gtrsim {10}^{12}{\mathrm{M}}_{\odot }{\mathrm{h}}^{-1}$, the average SFR as a function of halo mass follows a double power law trend that is common to all models, while differences occur at smaller masses. In particular, we find that models with a suppressed low-mass halo abundance exhibit higher SFR compared to the CDM results. Thus, different DM models predict a different faint-end slope of the LF which causes the goodness of fit to vary within each DM scenario for different model parameters. Using deviance statistics, we obtain a lower limit on the WDM thermal relic particle mass, $m_{\mathrm{WDM}}\gtrsim 1.5\mathrm{keV}$ at $2\sigma$. In the case of LFDM models, the phase transition redshift parameter is bounded to $z_t\gtrsim 8\times {10}^5$ at $2\sigma$. We find ultralight axion dark matter best-fit models with axion mass $m_a\gtrsim 1.6\times {10}^{-22}\mathrm{eV}$ to be well within $2\sigma$ of the deviance statistics. We remark that measurements at $z=6$ slightly favor a flattening of the LF at faint UV magnitudes. This tends to prefer some of the non-CDM models in our simulation suite, although not at a statistically significant level to distinguish them from CDM.

We study the matter bispectrum of large-scale structure by comparing the predictions of different perturbative and phenomenological models with the full three-dimensional bispectrum from $N$-body simulations estimated using modal methods. We show that among the perturbative approaches, effective field theory succeeds in extending the range of validity furthest on intermediate scales, at the cost of free additional parameters. By studying the halo model, we show that although it is satisfactory in the deeply nonlinear regime, it predicts a deficit of power on intermediate scales, worsening at redshifts $z>0$. By comparison with the $N$-body bispectrum on those scales, we show that there is a significant squeezed component underestimated in the halo model. On the basis of these results, we propose a new “three-shape” model, based on the tree-level, squeezed and constant bispectrum shapes we identified in the halo model; after calibration this fits the simulations on all scales and redshifts of interest. We extend this model further to primordial non-Gaussianity of the local and equilateral types by showing that the same shapes can be used to describe the additional non-Gaussian component in the matter bispectrum. This method provides a halofit-like prototype of the bispectrum that could be used to describe and test parameter dependencies and should be relevant for the bispectrum of weak gravitational lensing and wider applications.

We derive a direct correlation between the power spectrum and bispectrum of the primordial curvature perturbation in terms of the Goldstone mode based on the effective field theory approach to inflation. We show examples of correlated bispectra for the parametrized feature models presented by the Planck collaboration. We also discuss the consistency relation and the validity of our explicit correlation between the power spectrum and bispectrum.

Current and future neutrino experiments can be used to discover dark matter, not only in searches for dark matter annihilating to neutrinos, but also in scenarios where dark matter itself scatters off standard model particles in the detector. In this work, we study the sensitivity of different neutrino detectors to a class of models called boosted dark matter, in which a subdominant component of a dark sector acquires a large Lorentz boost today through annihilation of a dominant component in a dark matter-dense region, such as the galactic Center or dwarf spheroidal galaxies. This analysis focuses on the sensitivity of different neutrino detectors, specifically the Cherenkov-based Super-K and the future argon-based DUNE to boosted dark matter that scatters off electrons. We study the dependence of the expected limits on the experimental features, such as energy threshold, volume and exposure in the limit of constant scattering amplitude. We highlight experiment-specific features that enable current and future neutrino experiments to be a powerful tool in finding signatures of boosted dark matter.

Sterile neutrinos can be generated in the early universe through oscillations with active neutrinos and represent a popular and well-studied candidate for our Universe’s dark matter. Stringent constraints from X-ray and gamma-ray line searches, however, have excluded the simplest of such models. In this paper, we propose a novel alternative to the standard scenario in which the mixing angle between the sterile and active neutrinos is a dynamical quantity, induced through interactions with a light axionlike field. As the energy density of the axionlike particles is diluted by Hubble expansion, the degree of mixing is reduced at late times, suppressing the decay rate and easily alleviating any tension with X-ray or gamma-ray constraints. We present a simple model which illustrates the phenomenology of this scenario, and also describe a framework in which the QCD axion is responsible for the production of sterile neutrinos in the early universe.

The Standard Model extension (SME) parametrizes all possible Lorentz-violating contributions to the Standard Model and general relativity. It can be considered as an effective framework to describe possible quantum-gravity effects for energies much below the Planck energy. In the current paper, the spin-nondegenerate operators of the SME fermion sector are the focus. The propagators, energies, and solutions to the modified Dirac equation are obtained for several families of coefficients including nonminimal ones. The particle energies and spinors are computed at first order in Lorentz violation and, with the optical theorem, they are shown to be consistent with the propagators. The optical theorem is then also used to derive the matrices formed from a spinor and its Dirac conjugate at all orders in Lorentz violation. The results are the first explicit ones derived for the spin-nondegenerate operators. They will prove helpful for future phenomenological calculations in the SME that rely on the footing of quantum field theory.

The dark sector may contain a dark photon that kinetically mixes with the Standard Model photon, allowing dark matter to interact weakly with normal matter. In previous work we analyzed the implications of this scenario for dark matter capture by the Sun. Dark matter will gather in the core of the Sun and annihilate to dark photons. These dark photons travel outwards from the center of the Sun and may decay to produce positrons that can be detected by the Alpha Magnetic Spectrometer (AMS-02) on the International Space Station. We found that the dark photon parameter space accessible to this analysis is largely constrained by strong limits on the spin-independent weakly interacting massive particle–nucleon cross section from direct detection experiments. In this paper we build upon previous work by considering the case where the dark sector contains two species of Dirac fermion that are nearly degenerate in mass and couple inelastically to the dark photon. We find that for small values of the mass splitting $\mathrm{\Delta }\sim 100\mathrm{keV}$, the predicted positron signal at AMS-02 remains largely unchanged from the previously considered elastic case, while constraints from direct detection are relaxed. As such, there remains a region of parameter space with dark matter mass $100\mathrm{GeV}\lesssim m_X\lesssim 10\mathrm{TeV}$, dark photon mass $1\mathrm{MeV}\lesssim m_{A^{\prime }}\lesssim 100\mathrm{MeV}$, and kinetic mixing parameter ${10}^{-9}\lesssim ϵ\lesssim {10}^{-8}$ that is untouched by supernova observations and fixed target experiments but where an inelastic dark sector may still be discovered using existing AMS-02 data.

We investigate the phase structure of QCD with three degenerate quark flavors as a function of the degenerate quark masses at vanishing baryon number density. We use the highly improved staggered quarks on lattices with temporal extent $N_{\tau }=6$ and perform calculations for six values of quark masses, which in the continuum limit correspond to pion masses in the range $80\mathrm{MeV}\lesssim m_{\pi }\lesssim 230\mathrm{MeV}$. By analyzing the volume and temperature dependence of the chiral condensate and chiral susceptibility, we find no direct evidence for a first-order phase transition in this range of pion mass values. Relying on the universal scaling behaviors of the chiral observables near an anticipated chiral critical point, we estimate an upper bound for the critical pion mass, $m_{\pi }^c\lesssim 50\mathrm{MeV}$, below which a region of first-order chiral phase transition is favored.

We present measurements of a combination of the decay constants of the light pseudoscalar mesons and the gradient flow scale $t_0$, which allow us to set the scale of the lattices generated by CLS with $2+1$ flavors of nonperturbatively improved Wilson fermions. Mistunings of the quark masses are corrected for by measuring the derivatives of observables with respect to the bare quark masses.

The Dirac operator in finite-temperature QCD is equivalent to the Hamiltonian of an unconventional Anderson model, with on-site noise provided by the fluctuations of the Polyakov lines. The main features of its spectrum and eigenvectors, concerning the density of low modes and their localization properties, are qualitatively reproduced by a toy-model random Hamiltonian, based on an Ising-type spin model mimicking the dynamics of the Polyakov lines. Here we study the low modes of this toy model in the vicinity of the ordering transition of the spin model, and show that at the critical point the spectral density at the origin has a singularity, and the localization properties of the lowest modes change. This provides further evidence of the close relation between deconfinement, chiral transition, and localization of the low modes.

We present for the first time the complete twist-4 result for the semi-inclusive deeply inelastic scattering $e^{-}N\to e^{-}qX$ with polarized electron and proton beams at the tree level of perturbative QCD. The calculations have been carried out using the formalism obtained after collinear expansion where the multiple gluon scatterings are taken into account and gauge links are obtained automatically in a systematical way. The results show in particular that there are twist-4 contributions to all the eight twist-2 structure functions for $e^{-}N\to e^{-}hX$ that correspond to the eight twist-2 transverse-momentum-dependent parton distribution functions. Such higher-twist effects could be very significant and therefore have important impacts on extracting these three-dimensional parton distribution functions from the asymmetry data on $e^{-}N\to e^{-}hX$. We suggest also an approximate way to obtain a rough estimation of such higher-twist contributions.