We analyze the kinematics of cosmological spacetimes with nonzero torsion, in the framework of the classical Einstein-Cartan gravity. After a brief introduction to the basic features of spaces with nonvanishing torsion, we consider a family of observers moving along timelike worldlines and focus on their kinematic behavior. In so doing, we isolate the irreducible variables monitoring the observers’ motion and derive their evolution formulas and associated constraint equations. Our aim is to identify the effects of spacetime torsion, and the changes they introduce into the kinematics of the standard, torsion-free, cosmological models. We employ a fully geometrical approach, imposing no restrictions on the material content, or any a priori couplings between torsion and spin. Also, we do not apply the familiar splitting of the equations, into a purely Riemannian component plus a torsion/spin part, at the start of our study, but only introduce it at the very end. With the general formulas at hand, we use the Einstein-Cartan field equations to incorporate explicitly the spin of the matter. The resulting formulas fully describe the kinematics of dynamical spacetimes within the framework of the Einstein-Cartan gravity, while in the special case of the so-called Weyssenhoff fluid, they recover results previously reported in the literature.

A canonical analysis for general relativity is performed on a null surface without fixing the diffeomorphism gauge, and the canonical pairs of configuration and momentum variables are derived. Next to the well-known spin-2 pair, also spin-1 and spin-0 pairs are identified. The boundary action for a null boundary segment of spacetime is obtained, including terms on codimension two corners.

Here we have shown that asymptotically anti–de Sitter (AdS) black holes in the Einstein-Gauss-Bonnet (GB) theory are unstable under linear perturbations of space-time in some region of parameters. This (eikonal) instability develops at high multipole numbers. We found the exact parametric regions of the eikonal instability and extended this consideration to asymptotically flat and de Sitter cases. The approach to the threshold of instability is driven by purely imaginary quasinormal modes, which are similar to those found recently in Grozdanov, Kaplis, and Starinets, [J. High Energy Phys. 07 (2016) 151] for the higher curvature corrected black hole with the planar horizon. The found instability may indicate limits of holographic applicability of the GB-AdS backgrounds. Recently, through the analysis of critical behavior in AdS space-time in the presence of the Gauss-Bonnet term, it was shown [Deppe et al, Phys. Rev. Lett. 114, 071102 (2015)], that, if the total energy content of the AdS space-time is small, then no black holes can be formed with mass less than some critical value. A similar mass gap was also found when considering collapse of mass shells in asymptotically flat Gauss-Bonnet theories [Frolov, Phys. Rev. Lett. 115, 051102 (2015)]. The found instability of all sufficiently small Einstein-Gauss-Bonnet-AdS, dS and asymptotically flat black holes may explain the existing mass gaps in their formation.

Nonminimally coupled inflation models based on a nonminimal coupling $\xi {\varphi }^{2}R$ and a ${\varphi }^4$ potential are in excellent agreement with the scalar spectral index observed by Planck. Here we consider the modification of these models by a conformal factor with a zero. This enables a nonminimally coupled model to have a Planck-scale potential energy density at large values of the inflaton field, which can account for the smooth, potential-dominated volume that is necessary for inflation to start. We show that models with a conformal factor zero generally predict a correlated increase of the spectral index $n_s$ and tensor-to-scalar ratio $r$. For values of $n_s$ that are within the present $2-\sigma$ bounds from Planck, modification by $\mathrm{\Delta }r$ as large as 0.0013 is possible, which is large enough to be measured by next generation cosmic microwave background polarization satellites.

Observations of cosmic infrared background (CIB) radiation exhibit significant fluctuations on small angular scales. A number of explanations have been put forth, but there is currently no consensus on the origin of these large fluctuations. We consider the possibility that small-scale fluctuations in matter-antimatter asymmetry could lead to variations in star formation rates which are responsible for the CIB fluctuations. We show that the recently proposed Higgs relaxation leptogenesis mechanism can produce such small-scale baryonic isocurvature perturbations which can explain the observed excess in the CIB fluctuations.

If scale invariance exists in nature, the so-called “unparticle physics” may become part of reality. The only way to refute or confirm this idea is through experiments, such as those at the Large Hadron Collider (LHC). One of the peculiar properties of the unparticle stuff is that it gives striking multiphoton signals which have been studied through only the unparticle self-interactions. By considering not only the self-interactions of unparticles but also all the other possible contributions, which are dominant, a detailed study of the processes, within a scalar unparticle scenario, $pp\to 4\gamma$, $pp\to 2\gamma 2g$, $pp\to 2\gamma 2\ell$, $pp\to 4e$, $pp\to 4\mu$ and $pp\to 2e2\mu$ at $\sqrt{s}=14\mathrm{TeV}$ at the LHC is carried out. We use basic selection cuts and analyze various distributions to discriminate the signals over the Standard Model backgrounds and discuss what seems to be the most likely channel among the above for an indirect manifestation of unparticle effects. We follow a new approach to tackle the issue with the three-point correlation function for the scalar unparticle self-interactions. We also obtain the exclusion region in the unparticle parameter space from the available two-photon data of the LHC and compare it with the existing bounds coming from other sources.

We perform an in-depth analysis of the Higgs sector in the minimal left-right symmetric model and compute the scalar mass spectrum and associated mixings, offering simple physical and symmetry arguments in support of our findings. We identify the tree-level quartic and cubic potential couplings in terms of the physical states and compute the quantum corrections for the latter ones. The deviations from the standard model prediction of the cubic Higgs doublet coupling are considered. Moreover we discuss the possible implications concerning the stability of the potential under the renormalization-group-equations evolution. In particular we examine three possible energy scales of parity restoration: LHC reach, next hadronic collider and very high energy relevant for grand unification.

We analyze the pressure and density equations of state of unpolarized nonrelativistic fermions at finite temperature in one spatial dimension with contact interactions. For attractively interacting regimes, we perform a third-order lattice perturbation theory calculation, assess its convergence properties by comparing with hybrid Monte Carlo results (there is no sign problem in this regime), and demonstrate agreement with real Langevin calculations. For repulsive interactions, we present lattice perturbation theory results as well as complex Langevin calculations, with a modified action to prevent uncontrolled excursions in the complex plane. Although perturbation theory is a common tool, our implementation of it is unconventional; we use a Hubbard-Stratonovich transformation to decouple the system and automate the application of Wick’s theorem, thus generating the diagrammatic expansion, including symmetry factors, at any desired order. We also present an efficient technique to tackle nested Matsubara frequency sums without relying on contour integration, which is independent of dimension and applies to both relativistic and nonrelativistic systems, as well as all energy-independent interactions. We find exceptional agreement between perturbative and nonperturbative results at weak couplings, and furnish predictions based on complex Langevin at strong couplings. We additionally present perturbative calculations of up to the fifth-order virial coefficient for repulsive and attractive couplings. Both the lattice perturbation theory and complex Langevin formalisms can easily be extended to a variety of situations including polarized systems, bosons, and higher dimension.

We calculate the two leading-twist transverse momentum dependent distribution functions of the pion meson, the unpolarized distribution $f_{1\pi }(x,{\mathit{k}}_T^2)$ and the Boer-Mulders function $h_{1\pi }^{\perp }(x,{\mathit{k}}_T^2)$, using the pion wave functions derived from a light-cone approach. The evolution effect of the first ${\mathit{k}}_T$-moment of the pion Boer-Mulders function is studied by employing an approximate evolution kernel. Using the model resulting distributions, we predict the transverse momentum weighted $\cos 2\varphi$ azimuthal asymmetry in the unpolarized ${\pi }^{-}p$ Drell-Yan process which can be measured at COMPASS in the near future.

We report the first measurement of the full angular distribution for inclusive $J/\psi \to {\mu }^{+}{\mu }^{-}$ decays in $p+p$ collisions at $\sqrt{s}=510\mathrm{GeV}$. The measurements are made for $J/\psi$ transverse momentum $2<p_T<10\mathrm{GeV}/c$ and rapidity $1.2<y<2.2$ in the Helicity, Collins-Soper, and Gottfried-Jackson reference frames. In all frames the polar coefficient ${\lambda }_{\theta }$ is strongly negative at low $p_T$ and becomes close to zero at high $p_T$, while the azimuthal coefficient ${\lambda }_{\varphi }$ is close to zero at low $p_T$, and becomes slightly negative at higher $p_T$. The frame-independent coefficient $\tilde{\lambda }$ is strongly negative at all $p_T$ in all frames. The data are compared to the theoretical predictions provided by nonrelativistic quantum chromodynamics models.

The coalescence of compact objects is one of the most promising sources, as well as the source of the first detections, of gravitational waves for ground-based interferometric detectors, such as advanced LIGO and Virgo. Generically, compact objects in binaries are expected to be spinning with spin angular momenta misaligned with the orbital angular momentum, causing the orbital plane to precess. This precession adds rich structure to the gravitational waves, introducing such complexity that an analytic closed-form description has been unavailable until now. We here construct the first closed-form frequency-domain gravitational waveforms that are valid for generic spin-precessing quasicircular compact binary inspirals. We first construct time-domain gravitational waves by solving the post-Newtonian precession equations of motion with radiation reaction through multiple scale analysis. We then Fourier transform these time-domain waveforms with the method of shifted uniform asymptotics to obtain closed-form expressions for frequency-domain waveforms. We study the accuracy of these analytic, frequency-domain waveforms relative to waveforms obtained by numerically evolving the post-Newtonian equations of motion and find that they are suitable for unbiased parameter estimation for 99.2%(94.6%) of the binary configurations we studied at a signal-to-noise ratio of 10(25). These new frequency-domain waveforms could be used for detection and parameter estimation studies due to their accuracy and low computational cost.

The center of the Milky Way is predicted to be the brightest region of $\gamma$-rays generated by self-annihilating dark matter particles. Excess emission about the Galactic center above predictions made for standard astrophysical processes has been observed in $\gamma$-ray data collected by the Fermi Large Area Telescope. It is well described by the square of a Navarro, Frenk, and White dark matter density distribution. Although other interpretations for the excess are plausible, the possibility that it arises from annihilating dark matter is valid. In this paper, we characterize the excess emission as annihilating dark matter in the framework of an effective field theory. We consider the possibility that the annihilation process is mediated by either pseudoscalar or vector interactions and constrain the coupling strength of these interactions by fitting to the Fermi Large Area Telescope data for energies 1–100 GeV in the $15°\times 15°$ region about the Galactic center using self-consistently derived interstellar emission models and point source lists for the region. The excess persists and its spectral characteristics favor a dark matter particle with a mass in the range approximately from 50 to 190 (10 to 90) GeV and annihilation cross section approximately from $1\times {10}^{-26}$ to $4\times {10}^{-25}$ ($6\times {10}^{-27}$ to $2\times {10}^{-25}$) ${\mathrm{cm}}^3/\mathrm{s}$ for pseudoscalar (vector) interactions. We map these intervals into the corresponding WIMP-neutron scattering cross sections and find that the allowed range lies well below current and projected direct detection constraints for pseudoscalar interactions, but are typically ruled out for vector interactions.

The conserved magnetic flux of $U(1)$ electrodynamics coupled to matter in four dimensions is associated with a generalized global symmetry. We study the realization of such a symmetry at finite temperature and develop the hydrodynamic theory describing fluctuations of a conserved 2-form current around thermal equilibrium. This can be thought of as a systematic derivation of relativistic magnetohydrodynamics, constrained only by symmetries and effective field theory. We construct the entropy current and show that at first order in derivatives, there are seven dissipative transport coefficients. We present a universal definition of resistivity in a theory of dynamical electromagnetism and derive a direct Kubo formula for the resistivity in terms of correlation functions of the electric field operator. We also study fluctuations and collective modes, deriving novel expressions for the dissipative widths of magnetosonic and Alfvén modes. Finally, we demonstrate that a nontrivial truncation of the theory can be performed at low temperatures compared to the magnetic field: this theory has an emergent Lorentz invariance along magnetic field lines, and hydrodynamic fluctuations are now parametrized by a fluid tensor rather than a fluid velocity. Throughout, no assumption is made of weak electromagnetic coupling. Thus, our theory may have phenomenological relevance for dense electromagnetic plasmas.

The scalar septet model extends the standard model Higgs sector by an isospin septet with hypercharge chosen to preserve $\rho \equiv M_W^2/M_Z^2{\cos }^2{\theta }_W=1$. In this paper we constrain the model at high septet masses using perturbative unitarity of longitudinal vector boson scattering amplitudes. We also apply the constraints from LHC searches for doubly-charged Higgs bosons produced in vector boson fusion, which constrain the model at lower septet masses. We point out some important differences between the septet model and extended Higgs models that preserve custodial symmetry in the scalar spectrum.

For ultrarelativistic proton-proton and proton-nucleus collisions, we perform an exploratory study of the contribution to the elliptic flow $v_2$ coming from the orientation of the momentum of the produced particles with respect to the reaction plane. Via the color glass condensate factorization valid at high energies, this contribution is related to the orientation of a color dipole with respect to its impact parameter, which in turn probes the transverse inhomogeneity in the target. Using the McLerran-Venugopalan model (with impact-parameter dependence) as an effective description for the soft gluon distribution in the (proton or nuclear) target, we present a semianalytic calculation of the dipole-scattering amplitude, including its angular dependence. We find that the angular dependence is controlled by soft gluon exchanges and hence is genuinely nonperturbative. The effects of multiple scattering turn out to be essential (in particular, they change the sign of $v_2$). We find that sizable values for $v_2$, comparable to those observed in the LHC data and having a similar dependence upon the transverse momenta of the produced particles, can be easily generated via peripheral collisions. In particular, $v_2$ develops a peak at a transverse momentum that scales with the saturation momentum in the target.

We present an updated study of transverse single-spin asymmetries for the inclusive large-$P_T$ processes $\ell p^{\uparrow }\to hX$ and $\ell p^{\uparrow }\to \text{jet}X$, within a transverse momentum-dependent approach, including the contribution of quasireal (Weizsäcker-Williams) photons. In the spirit of a unified transverse momentum-dependent scheme, predictions are obtained adopting the Sivers and transversity distributions and the Collins fragmentation functions as extracted from fits to the azimuthal asymmetries measured in semi-inclusive deep inelastic scattering and $e^{+}{e}^{-}$ annihilation processes. The description of the available data is extremely good, showing a clear general improvement with respect to the previous leading-order analysis. Predictions for unpolarized cross sections and single-spin asymmetries for ongoing and future experiments are also given.

We study the smallest nontrivial matrix model that can be considered to be a (toy) model of a black hole. The model consists of a pair of $2\times 2$ traceless Hermitian matrices with a commutator squared potential and an $SU(2)$ gauge symmetry, plus an $SO(2)$ rotation symmetry. We show that using the symmetries of the system, all but two of the variables can be separated. The two variables that remain display chaos and a transition from chaos to integrability when a parameter related to an $SO(2)$ angular momentum is tuned to a critical value. We compute the Lyapunov exponents near this transition and study the critical exponent of the Lyapunov exponents near the critical point. We compare this transition to extremal rotating black holes.

The full resurgent trans-series is found exactly in near-supersymmetric $\mathbb{C}{P}^1$ quantum mechanics. By expanding in powers of the supersymmetry-breaking deformation parameter, we obtain the first and second expansion coefficients of the ground-state energy. They are an absolutely convergent series of nonperturbative exponentials corresponding to multibions with perturbation series on those backgrounds. We obtain all multibion exact solutions for a finite time interval in the complexified theory. We sum the semiclassical multibion contributions that reproduce the exact result supporting the resurgence to all orders. We also discuss the similar resurgence structure in $\mathbb{C}{P}^{N-1}$ ($N>2$) models. This is the first result in the quantum-mechanical model where the resurgent trans-series structure is verified to all orders in nonperturbative multibion contributions.