Axial-vector torsion in the Einstein-Cartan space $U_4$ is considered here. By picking a particular term from the $SO(4,1)$ Pontryagin density and then modifying it in a $SO(3,1)$ invariant way, we get a Lagrangian density with Lagrange multipliers. Then considering torsion and torsionless connection as independent fields, it has been found that $\kappa$ and $\lambda$ of Einstein-Hilbert Lagrangian, appear as integration constants in such a way that $\kappa$ has been found to be linked with the topological Nieh-Yan density of $U_4$ space.

We study in detail the quantum process in which a pair of black holes is created in a higher $D$-dimensional de Sitter (dS) background. The energy to materialize and accelerate the pair comes from the positive cosmological constant. The instantons that describe the process are obtained from the Tangherlini black hole solutions. Our pair creation rates reduce to the pair creation rate for Reissner-Nordström–dS solutions when $D=4$. Pair creation of black holes in the dS background becomes less suppressed when the dimension of the spacetime increases. The dS space is the only background in which we can discuss analytically the pair creation process of higher dimensional black holes, since the C-metric and the Ernst solutions, which describe, respectively, a pair accelerated by a string and by an electromagnetic field, are not known yet in a higher dimensional spacetime.

We study lepton flavor violating (LFV) $\tau$ and $B$ decays in models with heavy neutrinos to constrain the mixing matrix parameters $U_{\tau N}$. We find that the best current constraints when the heavy neutrinos are purely left handed come from LFV radiative $\tau$ decay modes. To obtain competitive constraints in LFV $B$ decay, it is necessary to probe $b\to X_s{\tau }^{\pm }{e}^{\mp }$ at the ${10}^{-7}$ level. When the heavy neutrinos have both left- and right-handed couplings, the mixing parameters can be constrained by studying LFV $B$ decay modes and LFV $\tau$ decay into three charged leptons. We find that the branching ratios $B({\tau }^{\pm }\to {\ell }_1^{\pm }{\ell }_2^{\pm }{\ell }_3^{\mp })$, $B(B_s\to {\tau }^{\pm }{e}^{\mp })$ and $B(b\to X_s{\ell }_1^{\pm }{\ell }_2^{\mp })$ need to be probed at the ${10}^{-8}$ level in order to constrain the mixing parameters beyond what is known from unitarity.

We show that ${\Sigma }^{+}$ hyperons produced by 800 GeV/c protons on targets of Be and Cu have significant polarizations (15–20%). These polarizations persist at values of $p_t\approx 2\mathrm{G}\mathrm{e}\mathrm{V}/\mathrm{c}$ and a wide range of $x_F$. The polarizations from the Cu target are consistently less than from Be. The average ratio of the ${\Sigma }^{+}$ polarization from Cu to that from Be is $0.68\pm 0.08$.

It was shown recently that in four dimensions scalar sources with fixed proper acceleration minimally coupled to a massless Klein-Gordon field lead to the same responses when they are (i) uniformly accelerated in Minkowski spacetime (in the inertial vacuum) and (ii) static in the Schwarzschild spacetime (in the Unruh vacuum). Here we show that this equivalence is broken if the spacetime dimension is more than four.

We discuss the definition of velocity as $dE/d|\mathbf{p}|$, where $E$, $\mathbf{p}$ are the energy and momentum of a particle, in doubly special relativity (DSR). If this definition matches $dx/dt$ appropriate for the space-time sector, then space-time can in principle be built consistently with the existence of an invariant length scale. We show that, within different possible velocity definitions, a space-time compatible with momentum-space DSR principles cannot be derived.

The action for the long wavelength oscillations of a non-BPS $\mathrm{p}=3$ brane embedded in $\mathrm{N}=1$, $\mathrm{D}=5$ superspace is determined by means of the coset method. The $\mathrm{D}=4$ world volume Nambu-Goldstone boson of broken translation invariance and the two $\mathrm{D}=4$ world volume Weyl spinor Goldstinos of the completely broken supersymmetry describe the excitations of the brane into the broken space and superspace directions. The resulting action is an invariant synthesis of the Akulov-Volkov and Nambu-Goto actions. The $\mathrm{D}=4$ antisymmetric tensor gauge theory action dual to the $\mathrm{p}=3$ brane action is determined.

The intuitive classical space-time picture breaks down in quantum gravity, which makes a comparison and the development of semiclassical techniques quite complicated. Using ingredients of the group averaging method to solve constraints one can nevertheless introduce a classical coordinate time into the quantum theory, and use it to investigate the way a semiclassical continuous description emerges from discrete quantum evolution. Applying this technique to test effective classical equations of loop cosmology and their implications for inflation and bounces, we show that the effective semiclassical theory is in good agreement with the quantum description even at short scales.

We generalize a class of magnetically charged black holes nonminimally coupled to two scalar fields previously found by one of us to the case of multiple scalar fields. The black holes possess a novel type of primary scalar hair, which we call a contingent primary hair: although the solutions possess degrees of freedom which are not completely determined by the other charges of the theory, the charges necessarily vanish in the absence of the magnetic monopole. Only one constraint relates the black hole mass to the magnetic charge and scalar charges of the theory. We obtain a Smarr-type thermodynamic relation, and the first law of black hole thermodynamics for the system. We further explicitly show in the two-scalar-field case that, contrary to the case of many other hairy black holes, the black hole solutions are stable to radial perturbations.

In this work we study scalar fields in a Friedmann-Robertson-Walker space-time. We use the invariant operator formulation of Lewis and Riesenfeld in order to study the behavior of scalar fields placed in the Friedmann-Robertson-Walker space-time. In addition, we construct the coherent states in this background and establish the existence of squeezed states.

We show that the abundance and redshift distribution ($dN/dz$) of galaxy clusters in future high-yield cluster surveys, combined with the spatial power spectrum [$P_c(k)$] of the same clusters, can place significant constraints on the evolution of the dark energy equation of state, $w=w(a)$. We evaluate the expected errors on $w_a=-dw/da$ and other cosmological parameters using a Fisher matrix approach, and simultaneously including cluster structure evolution parameters in our analysis. We study three different types of forthcoming surveys that will identify clusters based on their x-ray emission (such as DUO, the Dark Universe Observatory), their Sunyaev-Zel'dovich (SZ) decrement (such as SPT, the South Pole Telescope), or their weak-lensing shear (such as LSST, the Large Synoptic Survey Telescope). We find that combining the cluster abundance and power spectrum significantly enhances constraints from either method alone. We show that the weak-lensing survey can deliver a constraint as tight as $\Delta w_a\sim 0.1$ on the evolution of the dark energy equation of state, and that the x-ray and SZ surveys each yield $\Delta w_a\sim 0.4$ separately, or $\Delta w_a\sim 0.2$ when these two surveys are combined. For the x-ray and SZ surveys, constraints on dark energy parameters are improved by a factor of 2 by combining the cluster data with cosmic microwave background anisotropy measurements by Planck, but degrade by a factor of 2 if the survey is required to solve simultaneously for cosmological and cluster structure evolution parameters. The constraint on $w_a$ from the weak-lensing survey is improved by $\sim 25\%$ with the addition of Planck data.

Long-distance QCD effects in $B_{d,s}\to {\ell }^{+}{\ell }^{-}\gamma$ decays are analyzed. We show that the contribution of the light vector-meson resonances related to the virtual photon emission from valence quarks of the $B$-meson, which was not considered in previous analyses, strongly influences the dilepton differential distribution. Taking into account photon emission from the $b$-quark loop, weak annihilation, and Bremsstrahlung from leptons in the final state, we give predictions for dilepton spectrum in $B_{d,s}\to {\ell }^{+}{\ell }^{-}\gamma$ decays within the Standard Model.

In $60{\mathrm{p}\mathrm{b}}^{-1}$ of data taken on the $\psi (3770)$ resonance with the CLEO-c detector, we find eight $D^{+}\to {\mu }^{+}\nu$ decay candidates that are mostly signal, containing only one estimated background. Using this statistically compelling sample, we measure a value of $\mathcal{B}(D^{+}\to {\mu }^{+}\nu )=(3.5\pm 1.4\pm 0.6)\times {10}^{-4}$, and determine $f_{D^{+}}=(202\pm 41\pm 17)\mathrm{M}\mathrm{e}\mathrm{V}$.

Decays of the $\psi (2S)$ into vector plus pseudoscalar meson final states have been studied with $14\times {10}^6$ $\psi (2S)$ events collected with the BESII detector. Branching fractions of $\psi (2S)\to \varphi \eta$, $\varphi {\eta }^{\prime }$, and $\omega {\eta }^{\prime }$, and upper limits of $\psi (2S)\to \varphi {\pi }^0$ and $\omega \eta$ are obtained: $B\mathbf{(}\psi (2S)\to \varphi \eta \mathbf{)}=(3.3\pm 1.1\pm 0.5)\times {10}^{-5}$, $B\mathbf{(}\psi (2S)\to \varphi {\eta }^{\prime }\mathbf{)}=(3.1\pm 1.4\pm 0.7)\times {10}^{-5}$, and $B\mathbf{(}\psi (2S)\to \omega {\eta }^{\prime }\mathbf{)}=({3.2}_{-2.0}^{+2.4}\pm 0.7)\times {10}^{-5}$; and $B\mathbf{(}\psi (2S)\to \varphi {\pi }^0\mathbf{)}<0.40\times {10}^{-5}$, and $B\mathbf{(}\psi (2S)\to \omega \eta \mathbf{)}<3.1\times {10}^{-5}$ at the 90% C.L. These results are used to test the perturbative QCD “12% rule.”

For the first time, as far as we know, in field theory are found explicit forms of propagators satisfying the Källen-Lehmann representation. To be exact, it is shown that scalar meson propagators, taking into account a virtual intermediate state contribution to the resonance self-energy, satisfy the Källen-Lehmann representation in the wide domain of coupling constants of the light scalar mesons with the two-particle states. It is proposed to use these propagators in routine fitting data about light scalar mesons to reveal physics underlying the light scalar mesons.

The NuTeV anomaly of a nonuniversal value of the fundamental parameter ${sin}^2{\theta }_W$ in the electroweak theory has been interpreted as an indication for new physics beyond the standard model. However, the observed quantity depends on a possible asymmetry in the momentum distributions of strange quarks and antiquarks in the nucleon. This asymmetry occurs naturally in a phenomenologically successful physical model for such parton distributions, which reduces the NuTeV result to only about 2 standard deviations from the standard model.

We answer an important question in general relativity about the volume integral theorem for exotic matter by suggesting an exact integral quantifier for matter violating Averaged Null Energy Condition (ANEC). It is checked against some well-known static, spherically symmetric traversable wormhole solutions of general relativity with a sign reversed kinetic term minimally coupled scalar field. The improved quantifier is consistent with the principle that traversable wormholes can be supported by arbitrarily small quantities of exotic matter.

Recently, there has been much attention devoted to resolving the quantum corrections to the Bekenstein-Hawking (black hole) entropy. In particular, many researchers have expressed a vested interest in fixing the coefficient of the subleading logarithmic term. In the current paper, we are able to make some degree of progress in this direction by utilizing the generalized uncertainty principle (GUP). Notably, the GUP reduces to the conventional Heisenberg relation in situations of weak gravity but transcends it when gravitational effects can no longer be ignored. Ultimately, we formulate the quantum-corrected entropy in terms of an expansion that is consistent with all previous findings. Moreover, we demonstrate that the logarithmic prefactor (indeed, any coefficient of the expansion) can be expressed in terms of a single parameter that should be determinable via the fundamental theory.

Starting with a post-Newtonian description of compact binary systems, we derive a set of equations that describes the evolution of the orbital angular momentum and both spin vectors during inspiral. We find regions of phase space that exhibit resonance behavior, characterized by small librations of the spin vectors around a fixed orientation. Because of the loss of energy and orbital angular momentum through radiation reaction, systems can eventually be captured into these resonance orientations. By investigating the long-term evolution of compact binaries with a variety of initial conditions, we find that the distribution in parameter space can be strongly affected by resonance captures. This has the effect of significantly reducing the size of search space for gravitational wave sources, in turn improving the chances of detecting such sources through methods of template matching. Furthermore, by calculating the expected spin distribution at the end of the inspiral phase, we can predict what are the most likely initial conditions for the plunge phase, a result of great interest for numerical relativity calculations.