It is a known result by Jacobson that the flux of energy matter through a local Rindler horizon is related with the expansion of the null generators in a way that mirrors the first law of thermodynamics. We extend such a result to a timelike screen of observers with finite acceleration. Since timelike curves have more freedom than null geodesics, the construction is more involved than Jacobson’s and few geometrical constraints need to be imposed: the observers’ acceleration has to be constant in time and everywhere orthogonal to the screen. Moreover, at any given time, the extrinsic curvature of the screen has to be flat. The latter requirement can be weakened by asking that the extrinsic curvature, if present at the beginning, evolves in time like on a cone and just rescales proportionally to the expansion.

We calculate the probability distribution function (PDF) of the expected annihilation luminosities of dark matter subhalos as a function of subhalo mass and distance from the Galactic center using a semianalytical model of halo evolution. We find that the PDF of luminosities is relatively broad, exhibiting a spread of as much as an order of magnitude at fixed subhalo mass and halo-centric distance. The luminosity PDF allows for simple construction of mock samples of $\gamma$-ray luminous subhalos and assessment of the variance in the predicted $\gamma$-ray signals from dark matter annihilation. Other applications include quantifying the variance among the expected luminosities of dwarf spheroidal galaxies, assessing the level at which dark matter annihilation can be a contaminant in the expected $\gamma$-ray signal from other astrophysical sources, as well as estimating the level at which nearby subhalos can contribute to the antimatter flux.

Certain scalar-tensor theories exhibit the so-called chameleon mechanism, whereby observational signatures of scalar fields are hidden by a combination of self-interactions and interactions with ambient matter. Not all scalar-tensor theories exhibit such a chameleon mechanism, which has been originally found in models with inverse power runaway potentials and field-independent couplings to matter. In this paper we investigate field theories with field-dependent couplings and a power-law potential for the scalar field. We show that the theory indeed is a chameleon field theory. We find the thin-shell solution for a spherical body and investigate the consequences for Eöt-Wash experiments, fifth-force searches and Casimir-force experiments. Requiring that the scalar field evades gravitational tests, we find that the coupling is sensitive to a mass scale which is of order of the Hubble scale today.

We extend the Polyakov-loop extended Nambu–Jona-Lasinio model by introducing an effective four-quark vertex depending on the Polyakov loop. The effective vertex generates entanglement interactions between the Polyakov loop and the chiral condensate. The new model is consistent with lattice QCD data at imaginary quark-number chemical potential and real and imaginary isospin chemical potentials, particularly on the strong correlation between the chiral and deconfinement transitions and also on the quark-mass dependence of the order of the Roberge-Weiss endpoint. We investigate the influence of the entanglement interactions on the location of the tricritical point at real isospin chemical potential and on the location of the critical endpoint at real quark-number chemical potential.

A possibility of formation of static dual scalar and pseudoscalar density wave condensates in dense quark matter is considered for the Nambu–Jona-Lasinio model in an external magnetic field. Within a mean-field approximation, the effective potential of the theory is obtained and its minima are numerically studied; a phase diagram of the system is constructed. It is shown that the presence of a magnetic field favors the formation of spatially inhomogeneous condensate configurations at low temperatures and arbitrary nonzero values of the chemical potential.

The lightest supersymmetric particle may decay with branching ratios that correlate with neutrino oscillation parameters. In this case the CERN Large Hadron Collider (LHC) has the potential to probe the atmospheric neutrino mixing angle with sensitivity competitive to its low-energy determination by underground experiments. Under realistic detection assumptions, we identify the necessary conditions for the experiments at CERN’s LHC to probe the simplest scenario for neutrino masses induced by minimal supergravity with bilinear $R$ parity violation.

We calculate the set of $O({\alpha }_s^2)$ corrections to the branching ratio and to the photon energy spectrum of the decay process $\overline{B}\to X_s\gamma$ originating from the interference of diagrams involving the electromagnetic dipole operator $O_7$ with diagrams involving the chromomagnetic dipole operator $O_8$. The corrections evaluated here are one of the elements needed to complete the calculations of the $\overline{B}\to X_s\gamma$ branching ratio at next-to-next-to-leading order in QCD. We conclude that this set of corrections does not change the central value of the standard model prediction for $\mathrm{Br}(\overline{B}\to X_s\gamma )$ by more than 1%.

We study dark matter (DM) in the model with one keV scale right-handed neutrino ${\nu }_{R1}$ and two GeV scale right-handed neutrinos ${\nu }_{R2,3}$, the $\nu \mathrm{SM}$. We find that one of the GeV scale right-handed neutrinos can have a much longer lifetime than the other when two GeV scale right-handed neutrinos are degenerate. We show that the mass and mixing of light neutrinos can be explained in this case. Significant entropy release can be generated in a reheating produced by the decay of one of the GeV scale ${\nu }_R$. The density of ${\nu }_{R1}$ DM can be diluted by 2 orders of magnitude, and the mixing of ${\nu }_{R1}$ with active neutrinos is allowed to be much larger, reaching the bound from x-ray observation. This mixing can lead to a sizable rate of ${\nu }_{R1}$ capture by radioactive nuclei. The ${\nu }_{R1}$ capture events are mono-energetic electrons with keV scale energy away from the beta decay spectrum. This is a new way to detect DM in the Universe.

We show by experiment that an electron impinging on an electric field that is of critical magnitude in its rest frame, may produce an electron-positron pair. Our measurements address higher-order QED, using the strong electric fields obtainable along particular crystallographic directions in single crystals. For the amorphous material our data are in good agreement with theory, whereas a discrepancy with theory on the magnitude of the trident enhancement is found in the precisely aligned case where the strong electric field acts.

We study the dynamical stability of holographic superconductors. We first classify perturbations around black hole background solutions into vector and scalar sectors by means of a 2-dimensional rotational symmetry. We prove the stability of the vector sector by explicitly constructing the positive definite Hamiltonian. To reveal a mechanism for the stabilization of a superconducting phase, we construct a quadratic action for the scalar sector. From the action, we see the stability of black holes near a critical point is determined by the equation of motion for a charged scalar field. We show the effective mass of the charged scalar field in hairy black holes is always above the Breitenlohner-Freedman bound near the critical point due to the backreaction of a gauge field. It implies the stability of the superconducting phase. We also argue that the stability continues away from the critical point.

The recent discovery of an explicit dynamical description of $p$-branes makes it possible to investigate the existence of intersection of such objects. We generalize the solutions depending on the overall transverse space coordinates and time to those which depend also on the relative transverse space and satisfy new intersection rules. We give classification of these dynamical intersecting brane solutions involving two branes, and discuss the application of these solutions to cosmology and show that these give Friedmann-Lemaitre-Robertson-Walker cosmological solutions. Finally, we construct the brane world models, using the (cut-)copy-paste method after compactifying the trivial spatial dimensions. We then find that interesting brane world models can be obtained from codimension-one branes and several static branes with higher codimensions. We also classify the behaviors of the brane world near the future/past singularity.

The bulk viscosity in spin-one color superconducting strange quark matter is calculated by taking into account the interplay between the nonleptonic and semileptonic week processes. In agreement with previous studies, it is found that the inclusion of the semileptonic processes may result in non-negligible corrections to the bulk viscosity in a narrow window of temperatures. The effect is generally more pronounced for pulsars with longer periods. Compared to the normal phase, however, this effect due to the semileptonic processes is less pronounced in spin-one color superconductors. Assuming that the critical temperature of the phase transition is much larger than 40 keV, the main effect of spin-one color superconductivity in a wide range of temperatures is an overall increase of the bulk viscosity with respect to the normal phase. The corresponding enhancement factor reaches up to about 9 in the polar and $A$ phases, about 25 in the planar phase, and about 29 in the color-spin-locked (CSL) phase. This factor is determined by the suppression of the nonleptonic rate in color superconducting matter and, therefore, may be even larger if all quark quasiparticles happen to be gapped.

The three-dimensional Abelian Chern-Simons theory coupled to a scalar and a fermionic field of arbitrary charge is considered in order to study conformal symmetry breakdown and the effective potential stability. We present an improved effective potential computation based on two-loop calculations and the renormalization group equation: The latter allows us to sum up series of terms in the effective potential where the power of the logarithms are one, two, and three units smaller than the total power of coupling constants (i.e., leading, next-to-leading, and next-to-next-to-leading logarithms). For the sake of this computation we determined the beta function of the fermion-fermion-scalar-scalar interaction and the anomalous dimension of the scalar field. We show that the improved effective potential provides a much more precise determination of the properties of the theory in the broken phase, compared to the standard effective potential obtained directly from the loop calculations. This happens because the region of the parameter space where dynamical symmetry breaking occurs is drastically reduced by the improvement discussed here.

Recently Kuzenko and McCarty observed the cancellation of 4-derivative terms in the $D=4$ $\mathcal{N}=1$ Volkov-Akulov supersymmetric action for the fermionic Nambu-Goldstone field. Here is presented a simple algebraic proof of the cancellation based on using the Majorana bispinors and Fierz identities. The cancellation shows a difference between the Volkov-Akulov action and the effective superfield action recently studied by Komargodski and Seiberg and containing one 4-derivative term. We find out that the cancellation effect takes place in coupling of the Nambu-Goldstone fermion with the Dirac field. Equivalence between the Komargodski-Seiberg (KS) and the Volkov-Akulov (VA) Lagrangians is proved up to the first order in the interaction constant of the Nambu-Goldstone (NG) fermions.

Dictated by the string theory and various higher dimensional scenarios, black holes in $D>4$-dimensional space-times must have higher curvature corrections. The first and dominant term is quadratic in curvature, and called the Gauss-Bonnet (GB) term. We shall show that although the Gauss-Bonnet correction changes black hole’s geometry only softly, the emission of gravitons is suppressed by many orders even at quite small values of the GB coupling. The huge suppression of the graviton emission is due to the multiplication of the two effects: the quick cooling of the black hole when one turns on the GB coupling and the exponential decreasing of the gray-body factor of the tensor type of gravitons at small and moderate energies. At higher $D$ the tensor gravitons emission is dominant, so that the overall lifetime of black holes with Gauss-Bonnet corrections is many orders larger than was expected. This effect should be relevant for the future experiments at the Large Hadron Collider (LHC).

We use the expression for the $S$ parameter in the perturbative region of the conformal window to establish its dependence on the explicit introduction of fermion masses. We demonstrate that the relative ordering with which one sends to zero either the fermion mass or the external momentum leads to drastically different limiting values of $S$. Our results apply to any fermion matter representation and can be used as benchmark for the determination of certain relevant properties of the conformal window of any generic vectorlike gauge theory with fermionic matter. We finally suggest the existence of a universal lower bound on the opportunely normalized $S$ parameter and explore its theoretical and phenomenological implications. Our precise results constitute an ideal framework to correctly interpret the lattice studies of the conformal window of strongly interacting theories.

We demonstrate that Michelson-Morley tests, which detect direction-dependent anisotropies in the speed of light, can also be used to place limits upon isotropic deviations of the vacuum speed of light from $c$, as described by the photon-sector standard model extension parameter ${\tilde{\kappa }}_{\mathrm{tr}}$. A shift in the speed of light that is isotropic in one inertial frame implies anisotropic shifts in others. Using observer Lorentz covariance, we derive the time-dependent variations in the relative resonance frequencies of a pair of electromagnetic resonators that would be generated by such a shift in the rest frame of the Sun. A new analysis of a recent experimental test of relativity using this result constrains ${\tilde{\kappa }}_{\mathrm{tr}}$ with a precision of $7.4\times {10}^{-9}$. This represents the first constraint on ${\tilde{\kappa }}_{\mathrm{tr}}$ by a Michelson-Morley experiment and the first analysis of a single experiment to simultaneously set limits on all nine nonbirefringent terms in the photon sector of the minimal standard model extension.

We study the lattice spacing dependence, or scaling, of physical quantities using the highly improved staggered quark (HISQ) action introduced by the HPQCD/UKQCD Collaboration, comparing our results to similar simulations with the asqtad fermion action. Results are based on calculations with lattice spacings approximately 0.15, 0.12, and 0.09 fm, using four flavors of dynamical HISQ quarks. The strange and charm quark masses are near their physical values, and the light-quark mass is set to 0.2 times the strange-quark mass. We look at the lattice spacing dependence of hadron masses, pseudoscalar meson decay constants, and the topological susceptibility. In addition to the commonly used determination of the lattice spacing through the static quark potential, we examine a determination proposed by the HPQCD Collaboration that uses the decay constant of a fictitious “unmixed $s\overline{s}$” pseudoscalar meson. We find that the lattice artifacts in the HISQ simulations are much smaller than those in the asqtad simulations at the same lattice spacings and quark masses.

The decay modes of the type $B\to \pi D$ are dynamically different. For the case $\overline{B_d^0}\to {\pi }^{-}{D}^{+}$ there is a substantial factorized contribution which dominates. In contrast, the decay mode $\overline{B_d^0}\to {\pi }^0{D}^0$ has a small factorized contribution, being proportional to a very small Wilson coefficient combination. In this paper we calculate the relevant Wilson coefficients at one loop level in the heavy quark limits, both for the $b$ quark and the $c$ quark. We also emphasize that for the decay mode $\overline{B_d^0}\to {\pi }^0{D}^0$ there is a sizeable nonfactorizable contribution due to long-distance interactions, which dominate the amplitude. We estimate the branching ratio for this decay mode within our framework, which uses the heavy quark limits, both for the $b$ and the $c$ quarks. In addition, we treat energetic light $(u,d,s)$ quarks within a variant of large energy effective theory and combine this with a new extension of chiral quark models in order to estimate the effect of soft-gluon emission. For reasonable values of the model-dependent parameters of our model, we can account for at least $3/4$ of the amplitude needed to explain the experimental branching ratio $\simeq 2.6\times {10}^{-4}$.

Analytic QCD models are those where the QCD running coupling has the physically correct analytic behavior, i.e., no Landau singularities in the Euclidean regime. We present a simple analytic QCD model in which the discontinuity function of the running coupling at high momentum scales is the same as in perturbative QCD (just like in the analytic QCD model of Shirkov and Solovtsov), but at low scales it is replaced by a delta function which parametrizes the unknown behavior there. We require that the running coupling agree to a high degree with the perturbative coupling at high energies, which reduces the number of free parameters of the model from four to one. The remaining parameter is fixed by requiring the reproduction of the correct value of the semihadronic tau decay ratio.