Physical Review D

We present a search for the radiative leptonic decay B⁺→ℓ⁺ν_ℓγ, where ℓ=e, μ, using a data sample of 465×10⁶ BB̅ pairs collected by the BABAR experiment. In this analysis, we fully reconstruct the hadronic decay of one of the B mesons in Υ(4S)→B⁺B^- decays, then search for evi...

We study charmless B⁺ meson decays to the pΛ̅ π⁺π^- final state using a 605  fb^-1 data sample collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e⁺e^- collider. There are significant signals found with the pΛ̅ mass peaking near threshold....

We report a measurement of the CP-odd fraction and the time-dependent CP violation in B⁰→D^*+D^*- decays, using 657×10⁶ BB̅ events collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e⁺e^- collider. We measure a CP-odd fraction of R_⊥=0.125±0.043(stat)...

The longitudinal spin transfer, D_LL, from high energy polarized protons to Λ and Λ̅ hyperons has been measured for the first time in proton-proton collisions at sqrt[s] =200  GeV with the STAR detector at the Relativistic Heavy Ion Collider. The measurements cover pseudorapidity, η,...

We report an improved measurement of D⁺→K_S⁰K⁺ and D_s⁺→K_S⁰π⁺ branching ratios using 605  fb^-1 of data collected with the Belle detector at the KEKB asymmetric-energy e^+e- collider. The measured branching ratios with respect to the Cabibbo-favored modes are B(D⁺→K_S⁰K⁺)/B(D⁺→K_S⁰π⁺)=0.1899...

In multi-Higgs-doublet models the alignment in flavor space of the relevant Yukawa matrices guarantees the absence of tree-level flavor-changing couplings of the neutral scalar fields. We analyze the consequences of this condition within the two-Higgs-doublet model and show that it leads to a generi...

We report measurements of the exclusive cross section for e⁺e^-→D⁰D^*-π⁺ as a function of center-of-mass energy from the D⁰D^*-π⁺ threshold to 5.2 GeV with initial-state radiation. No evidence is found for Y(4260)→D⁰D^*-π⁺ decays. The analysis is based on a data sample collected with the Belle d...

Solar and KamLAND data are in slight tension when interpreted in the standard two-flavor oscillations framework and this may be alleviated allowing for a nonzero value of the mixing angle θ₁₃. Here we show that, likewise, nonstandard flavor-changing interactions (FCI), possibly intervening in the p...

We study a new supersymmetric mechanism for lepton flavor violation in μ and Ï„ decays and μ→e conversion in nuclei, within a minimal extension of the minimal supersymmetric standard model with low-mass heavy singlet neutrinos and sneutrinos. We find that the decays μ→eγ, τ→eγ and τ→Î...

Some deviations from special relativity—especially isotropic effects—are most efficiently constrained using particles with velocities very close to 1. While there are extremely tight bounds on some of the relevant parameters coming from astrophysical observations, many of these rely on our havin...

We point out that mirror dark matter predicts low-energy (E_R≲2  keV) electron recoils from mirror electron scattering as well as nuclear recoils from mirror ion scattering. The former effect is examined and applied to the recently released low-energy electron recoil data from the CDMS Collabor...

We measure the rate of D⁰-D̅ ⁰ mixing with the observable y_CP=(τ_Kπ/τ_KK)-1, where τ_KK and τ_Kπ are, respectively, the mean lifetimes of CP-even D⁰→K⁺K^- and CP-mixed D⁰→K^-π⁺ decays, using a data sample of 384  fb^-1 collected by the BABAR detector at the SLAC PEP-II asymmetric-en...

We have developed an efficient simulation algorithm for strongly interacting relativistic fermions in two-dimensional field theories based on a formulation as a loop gas. It essentially eliminates critical slowing down by sampling two-point correlation functions and allows simulations directly in th...

D_s mesons are investigated in a semiclassic flux tube model where the spin-orbit interaction is taken into account. Spectrum of D-wave D_s is predicted. The predicted spectrum is much lower than most previous predictions. Analysis of some D_s candidates is made. D_sJ(2632)⁺ may be a 1^- j^P=3 / 2^...

We combine measurements of the top quark pair production cross section in pp̅ collisions in the ℓ+jets, ℓℓ, and τℓ final states (where ℓ is an electron or muon) at a center of mass energy of sqrt[s] =1.96  TeV in 1  fb^-1 of data collected with the D0 detector. For a top ...

Recently dispersion relations have been applied to hard exclusive processes such as deeply virtual Compton scattering, and a holographic principle was proposed that maps out the generalized parton distributions entering the soft matrix elements for the processes from their values on a given kinemati...

We propose a new mechanism for generating small neutrino masses which predicts the relation m_ν∼v⁴/M³, where v is the electroweak scale, rather than the conventional seesaw formula m_ν∼v²/M. Such a mass relation is obtained via effective dimension seven operators LLHH(H^†H)/M³, which arise when...

We present a search for associated production of the standard model Higgs boson and a Z boson where the Z boson decays to two leptons and the Higgs decays to a pair of b quarks in pp̅ collisions at the Fermilab Tevatron. We use event probabilities based on standard model matrix elements to...

We examine various direct and indirect constraints on the lepton-specific two-Higgs-doublet model and scrutinize the property of the Higgs bosons in the allowed parameter space. We find that in the allowed parameter space the CP-odd Higgs boson A is rather light (m_Alt;30  GeV with 95% possibili...

We present a search for charged Higgs bosons in decays of top quarks, in the mass range 80lt;m_H^±lt;155  GeV, assuming the subsequent decay H⁺→τ⁺ν_τ (and its charge conjugate). Using 0.9  fb^-1 of lepton+jets data collected with the D0 detector at the Fermilab Tevatron pp̅ col...

We examine current numerical relativity computations of gravitational waves, which typically determine the asymptotic waves at infinity by extrapolation from finite (small) radii. Using simulations of a black hole binary with accurate wave extraction at r=1000M, we show that extrapolations from the ...

We study the strong gravity regime in viable models of so-called f(R) gravity that account for the observed cosmic acceleration. In contrast with recent works suggesting that very relativistic stars might not exist in these models, we find numerical solutions corresponding to static star configurati...

We construct dark soliton solutions in a holographic model of a relativistic superfluid. We study the length scales associated with the condensate and the charge density depletion, and find that the two scales differ by a nontrivial function of the chemical potential. By adjusting the chemical poten...

We explore supersymmetry breaking in the light of a rich fixed-point structure of two-dimensional supersymmetric Wess-Zumino models with one supercharge using the functional renormalization group. We relate the dynamical breaking of supersymmetry to a renormalization group relevant control parameter...

Past and recent data analyses gave some hints of steps in dark energy. Considering dark energy as a dynamical scalar field, we investigate several models with various steps: a step in the scalar potential, a step in the kinetic term, a step in the energy density, and a step in the equation-of-state ...

We investigate the course of cosmic expansion in its recent past using the Constitution SN Ia sample, along with baryon acoustic oscillations (BAO) and cosmic microwave background (CMB) data. Allowing the equation of state of dark energy (DE) to vary, we find that a coasting model of the universe (q_...

Hořava-Lifshitz theory has been recently put forth as a proposal for a renormalizable theory of quantum gravity . It explicitly breaks Lorentz invariance, introducing an apparent extra scalar degree of freedom. I show that the low energy limit of (non-projectible) Hořava-Lifshitz gravity is unique...

It has recently been argued that the PAMELA, ATIC, and PPB-BETS data showing an anomalous excess of high-energy cosmic ray positrons and electrons might be explained by dark matter annihilating in the Galactic halo with a cross section resonantly enhanced compared to its value in the primeval plasma...

The full moments expansion of the joint probability distribution of an isotropic random field, its gradient, and invariants of the Hessian are presented in 2 and 3D. It allows for explicit expression for the Euler characteristic in ND and computation of extrema counts as functions of the excursion s...

Bekenstein’s tensor-vector-scalar (TeVeS) theory has had considerable success as a relativistic theory of modified Newtonian dynamics. However, recent work suggests that the dynamics of the theory are fundamentally flawed and numerous authors have subsequently begun to consider a generalization of...

We present a search for the radiative leptonic decay B⁺→ℓ+ν_ℓγ, where ℓ=e, μ, using a data sample of 465×10⁶ BB̅ pairs collected by the BABAR experiment. In this analysis, we fully reconstruct the hadronic decay of one of the B mesons in Υ(4S)→B⁺B^- decays, then search for evi...

We examine supersymmetric theories with approximately conformal sectors. Without an IR cutoff the theory has a continuum of modes, which are often referred to as “unparticles.” Making use of the AdS/CFT correspondence we find that in the presence of a soft-wall, a gap in the spectrum can arise, ...

The masses of the low-lying baryons are evaluated using two degenerate flavors of twisted mass sea quarks corresponding to pseudoscalar masses in the range of about 270–500 MeV. The strange valence quark mass is tuned to reproduce the mass of the kaon in the physical limit. The tree-level Symanzi...

We investigated the finite temperature (T) phase transition for SU(N_c) gauge theory with N_c=4, 6, 8 and 10 at lattice spacing, a, of 1/(6T) or less. We checked that these theories have first-order transitions at such small a. In many cases we were able to find the critical couplings with precision a...

The theoretical description of compact structures that share some features with mass varying particles allows for a simple analysis of the equilibrium and stability for massive stellar bodies. We investigate static, spherically symmetric solutions of Einstein equations for a system composed by nonba...

We explore potential of current and next-generation γ-ray telescopes for the detection of weak magnetic fields in the intergalactic medium. We demonstrate that using two complementary techniques, observation of extended emission around point sources and observation of time delays in γ-ray flares, ...

The dynamics of a cosmological model of dark matter and dark energy represented by a scalar field endowed with a cosh-like potential plus a cosmological constant is investigated in detail. By studying the appropriate phase space of the equations of motion, it is shown that a standard evolution of th...

If dark energy (DE) couples to neutrinos, then there may be apparent violations of Lorentz/CPT invariance in neutrino oscillations. The DE-induced Lorentz/CPT violation takes a specific form that introduces neutrino oscillations that are energy independent, differ for particles and antiparticles, an...

We give general sufficient conditions for the existence of trapped surfaces due to concentration of matter in spherically symmetric initial data sets satisfying the dominant energy condition. These results are novel in that they apply and are meaningful for arbitrary spacelike slices, that is, they ...

Binary black-hole systems with spins aligned or anti-aligned to the orbital angular momentum, and which therefore do not exhibit precession effects, provide the natural ground to start detailed studies of the influence of strong-field spin effects on gravitational-wave observations of coalescing bin...

The average transverse momentum transfer per unit path length to a fast parton scattering elastically in a perturbative quark-gluon plasma is related to the radiative energy loss of the parton. We first calculate the momentum transfer coefficient q-^ in terms of a classical Langevin problem...

We study a gauge/gravity model for the thermodynamics of a gauge theory with one running coupling. The gravity side contains an ansatz for the metric and a scalar field; on the field theory side one starts by giving an ansatz for the beta function describing the scale dependence of the coupling. The...

We prove the analyticity of the finite volume QCD partition function for complex values of the θ-vacuum parameter. The absence of singularities different from Lee-Yang zeros only permits ∧ cusp singularities in the vacuum energy density and never ∨ cusps. This fact together with the Vafa-Witten...

In a recent Brief Report by Shalaby, a new first-order perturbative calculation of the metric operator for an iϕ³ scalar field theory is given. It is claimed that the incorporation of derivative terms in the ansatz for the metric operator results in a local solution, in contrast to the nonlocal sol...

We examine current numerical relativity computations of gravitational waves, which typically determine the asymptotic waves at infinity by extrapolation from finite (small) radii. Using simulations of a black hole binary with accurate wave extraction at r=1000M, we show that extrapolations from the ...

The minimal supersymmetric standard model has several flat directions, which can naturally be excited during inflation. If they have a slow (perturbative) decay, they may affect the thermalization of the inflaton decay products. In the present paper, we consider the system of udd and QLd flat direct...

We construct charged and rotating asymptotically Schrödinger black hole solutions of type IIB supergravity. We begin by obtaining a closed-form expression for the null Melvin twist of a broad class of type IIB backgrounds, including solutions of minimal five-dimensional gauged supergravity, and i...

Infinite statistics in which all representations of the symmetric group can occur is known as a special case of quon theory. However, the validity of relativistic quon theories is still in doubt. In this paper we prove that there exists a relativistic quantum field theory which allows interactions i...

We present here a detailed derivation of an explicit spin-dependent expression for the bending angle of light as it traverses in the equatorial plane of a spinning black hole. We show that the deflection produced in the presence of the black hole angular momentum explicitly depends on whether the mo...

We prove that the light-cone time cutoff on the multiverse defines the same probabilities as a causal patch with initial conditions in the longest-lived metastable vacuum. This establishes the equivalence of two measures of eternal inflation which naively appear very different (though both are motiv...

Invoking the Peccei-Quinn (PQ) solution to the strong CP problem substitutes the puzzle of why θ_qcd is so small with the puzzle of why the PQ symmetry is of such high quality. Cosmological and astrophysical considerations raise further puzzles. This paper explores these issues in several contexts: ...

We study torus/orbifold models with magnetic flux and Wilson line backgrounds. The number of zero modes and their profiles depend on those backgrounds. That has interesting implications from the viewpoint of particle phenomenology.

In a previous work (arXiv:0902.3750 [hep-th]) we studied the world-sheet conformal invariance for superstrings in the type IIB R-R plane-wave in semi-light-cone gauge. Here we give further justification to the results found in that work through alternative arguments using dynamical supersymmetries. ...

We study the impact of cosmic inhomogeneities on the interpretation of observations. We build an inhomogeneous universe model without dark energy that can confront supernova data and yet is reasonably well compatible with the Copernican principle. Our model combines a relatively small local void, th...

Dark matter charged under a new gauge sector, as motivated by recent data, suggests a rich GeV-scale "dark sector" weakly coupled to the Standard Model by gauge kinetic mixing. The new gauge bosons can decay to Standard Model leptons, but this mode is suppressed if decays into lighter "dark sector" particles are kinematically allowed. These particles in turn typically have macroscopic decay lifetimes that are constrained by two classes of experiments, which we discuss. Lifetimes of 10 \cm <~ct <~108 \cm are constrained by existing terrestrial beam-dump experiments. If, in addition, dark matter captured in the Sun (or Earth) annihilates into these particles, lifetimes up to ~ 1015 \cm are constrained by solar observations. These bounds span fourteen orders of magnitude in lifetime, but they are not exhaustive. Accordingly, we identify promising new directions for experiments including searches for displaced di-muons in B-factories, studies at high-energy and -intensity proton beam dumps, precision gamma-ray and electronic measurements of the Sun, and milli-charge searches re-analyzed in this new context.

We have computed the full one-loop corrections (electroweak as well as QCD) to processes contributing to the relic density of dark matter in the MSSM where the LSP is the lightest neutralino. We cover scenarios where the most important channels are those with gauge boson pair production. This includes the case of a bino with some wino admixture, a higgsino and a wino. In this paper we specialise to the case of light dark matter much below the TeV scale. The corrections can have a non-negligible impact on the predictions and should be taken into account in view of the present and forthcoming increasing precision on the relic density measurements. Our calculations are made with the help of , an automatic tool for the calculation of one-loop processes in the MSSM. The renormalisation scheme dependence of the results as concerns \tgb is studied.

We study SU(2) lattice gauge theory with two flavours of Dirac fermions in the adjoint representation. We measure the running of the coupling in the Schr#246;dinger Functional (SF) scheme and find it is consistent with existing results. We discuss how systematic errors affect the evidence for an infrared fixed point (IRFP). We present the first measurement of the running of the mass in the SF scheme. The anomalous dimension of the chiral condensate, which is relevant for phenomenological applications, can be easily extracted from the running of the mass, under the assumption that the theory has an IRFP. At the current level of accuracy, we can estimate 0.05 < g < 0.56 at the IRFP.

We study the pseudoscalar glueball ground state in a chiral effective Lagrangian model proposed by 't Hooft, motivated by taking into account the instanton effects, which can describe not only the chiral symmetry breaking, but also the solution of UA(1). We study the parameter space allowed by constraints from vacuum conditions and unitary bounds. By considering two scenarios in 0++ sector, we find that parameter space which can accommodate the 0-+ sector is sensitive to the conditions in 0++ sector. From our analysis, it is found that three h states, i.e. h(1295), h(1405), h(1475), can be the pseudoscalar glueball ground state if we assume that the lightest 0++ glueball ground state has a mass 1710 (or 1500) MeV. While there will be no 0-+ glueball candidate ground state found in experiments if we assume that the lightest 0++ glueball ground state has a mass 660 MeV. We also point out the determined instanton density (i.e. the parameter kt) is consistent with those determined from other methods, e.g, instanton liquid approximation and lattice simulations.

Motivated by recent measurements of the top quark forward-backward asymmetry at the Tevatron, we study how t-channel new physics can contribute to a large value. We concentrate on a theory with an abelian gauge boson that possesses flavor changing couplings between up and top quarks but satisfies flavor physics constraints. Collider constraints are strong, but can be accommodated with the aid of small flavor diagonal couplings. We find that M\Zp 160nbsp;GeV can yield a total lab-frame asymmetry of ~ 18% without conflicting with other observables. There are implications for future collider searches, including exotic top quark decays, like-sign top quark production, and detailed measurements of the top production cross section. An alternate model with a gauged non-Abelian flavor symmetry has has similar phenomenology, but lacks the like-sign top signal.

It has been suggested that the volume dependence of the spectral weight could be utilized as a probe to distinguish single and multi-particle states in Monte Carlo simulations. In a recent study using a solvable model, the Lee model, we found that this criteria is not applicable for broad resonances. In this paper, the same question is addressed within the finite size formalism outlined by L#252;scher. Similar conclusion has been reached. This is first studied using a quantum mechanical scattering model. Then, following analogous arguments as in the original L#252;scher's formalism, the result is generalized to massive quantum field theories under the same conditions as the conventional L#252;scher's formulae. A possibility of extracting resonance parameters using the spectral weight function is also pointed out.

We study the SU(3) lattice gauge theory, with two flavors of sextet Wilson-clover fermions, near its finite-temperature phase transition. We find metastable states that have Wilson line expectation values whose complex phases are near 2p/3 or p. The true equilibrium phase at these couplings and temperatures has its Wilson line oriented only towards the positive real axis, in agreement with perturbation theory.

We explore the phase diagram and the critical behavior of QCD thermodynamic quantities in the context of the so-called Polyakov-Nambu-Jona-Lasinio model. We show that this improved field theoretical model is a successful candidate for studying the equation of state and the critical behavior around the critical end point. We argue that a convenient choice of the model parameters is crucial to get the correct description of isentropic trajectories. The effects of the regularization procedure in several thermodynamic quantities is also analyzed. The results are compared with simple thermodynamic expectations and lattice data.

We calculate the neutral kaon mixing parameter BK in unquenched lattice QCD using asqtad-improved staggered sea quarks and domain-wall valence quarks. We use the "2+1" flavor gauge configurations generated by the MILC Collaboration, and simulate with multiple valence and sea quark masses at two lattice spacings of a 0.12 fm and a 0.09 fm. We match the lattice determination of BK to the continuum value using the nonperturbative method of Rome-Southampton, and extrapolate BK to the continuum and physical quark masses using mixed action chiral perturbation theory. The "mixed-action" method enables us to control all sources of systematic uncertainty and therefore to precisely determine BK; we find a value of BK[`MS], NDR(2 GeV) = 0.527(6)(21), where the first error is statistical and the second is systematic.

We perform three-dimensional relativistic hydrodynamical simulations of the coalescence of strange stars and explore the possibility to decide on the strange matter hypothesis by means of gravitational-wave measurements. Selfbinding of strange quark matter and the generally more compact stars yield features that clearly distinguish strange star from neutron star mergers, e.g. hampering tidal disruption during the plunge of quark stars. Furthermore, instead of forming dilute halo structures around the remnant as in the case of neutron star mergers, the coalescence of strange stars results in a differentially rotating hypermassive object with a sharp surface layer surrounded by a geometrically thin, clumpy high-density strange quark matter disk. We also investigate the importance of including non-zero temperature equations of state in neutron star and strange star merger simulations. In both cases we find a crucial sensitivity of the dynamics and outcome of the coalescence to thermal effects, e.g. the outer remnant structure and the delay time of the dense remnant core to black hole collapse depend on the inclusion of non-zero temperature effects. For comparing and classifying the gravitational-wave signals, we use a number of characteristic quantities like the maximum frequency during inspiral or the dominant frequency of oscillations of the postmerger remnant. In general, these frequencies are higher for strange star mergers. Only for particular choices of the equation of state the frequencies of neutron star and strange star mergers are similar. In such cases additional features of the gravitational-wave luminosity spectrum like the ratio of energy emitted during the inspiral phase to the energy radiated away in the postmerger stage may help to discriminate coalescence events of the different types. If such characteristic quantities could be extracted from gravitational-wave signals, for instance with the upcoming gravitational-wave detectors, a decision on the strange matter hypothesis and the existence of strange stars should be possible.

We investigate the abundance of large-scale hot and cold spots in the WMAP-5 temperature maps and find considerable discrepancies compared to Gaussian simulations based on the LCDM best-fit model. Too few spots are present in the reliably observed CMB region, i.e. outside the foreground-contaminated parts excluded by the KQ75 mask. Even simulated maps created from the original WMAP-5 estimated multipoles contain more spots than visible in the measured CMB maps. A strong suppression of the lowest multipoles would lead to better agreement. The lack of spots is reflected in a low mean temperature fluctuation on scales of several degrees (4-8), which is only shared by less than 1% (0.16%-0.62%) of Gaussian LCDM simulations. After removing the quadrupole, the probabilities change to 2.5%-8.0%. This shows the importance of the anomalously low quadrupole for the statistical significance of the missing spots. We also analyze a possible violation of Gaussianity or statistical isotropy (spots are distributed differently outside and inside the masked region).

We investigate the vortex lattice solution in a (2+1)-dimensional holographic model of superconductors constructed from a charged scalar condensate. The solution is obtained perturbatively near the second-order phase transition and is a holographic realization of the Abrikosov lattice. Below a critical value of magnetic field, the solution has a lower free energy than the normal state. Both the free energy density and the superconducting current are expressed by nonlocal functions, but they reduce to the expressions in the Ginzburg-Landau (GL) theory at long wavelength. As a result, a triangular lattice becomes the most favorable solution thermodynamically as in the GL theory of type II superconductors.

Abstract. We show how to obtain a single chiral family of an SO(10) GUT, starting from a Majorana-Weyl representation of a unifying ("GraviGUT") group SO(3,11), which contains the gravitational Lorentz group \sothreeone. An action is proposed, which reduces to the correct fermionic GUT action in the broken phase.

We generalize the Swiss-cheese cosmologies so as to include non-zero linear momenta of the associated boundary surfaces. The evolution of mass scales in these generalized cosmologies is studied for a variety of models for the background without having to specify any details within the local inhomogeneities. We find that the final effective gravitational mass and size of the evolving inhomogeneities depends on their linear momenta but these properties are essentially unaffected by the details of the background model.

In this work, we explicitly evaluate the gauge propagator of the Maxwell theory supplemented by the CPT-even term of the SME. First, we specialize our evaluation for the parity-odd sector of the tensor Wmnrs,nbsp;using a parameterization that retains only the three nonbirefringent coefficients.nbsp;From the poles of the propagator, it is shown that nbsp;physical modes of this electrodynamics are stable, non-causal and unitary. In the sequel, we carry out the parity-even gauge propagator using a parametrization that allows to work with only the isotropic nonbirefringent element. In this case, we show that thenbsp;physical modes of the parity-even sector of the tensor W are causal, stable and unitary for a limited range of the isotropic coefficient.

When the last electron-photon scattering takes place in a magnetized environment, the degree of circular polarization of the outgoing radiation depends upon the magnetic field strength. After deriving the scattering matrix of the process, the generalized radiative transfer equations are deduced in the presence of the relativistic fluctuations of the geometry and for all the four brightness perturbations. The new system of equations is solved under the assumption that the incident radiation is not polarized. The induced V-mode polarization is analyzed both analytically and numerically. The corresponding angular power spectra are calculated and compared with the measured (or purported) values of the linear polarizations (i.e. E-mode and B-mode) as they arise in the concordance model and in its neighboring extensions. Possible connections between the V-mode polarization of the Cosmic Microwave background and the topological properties of the magnetic flux lines prior to equality are outlined and briefly explored in analogy with the physics of magnetized sun spots.

The WMAP haze is an excess in microwave emission coming from the center of the Milky Way galaxy. In the case of synchrotron emission models of the haze, we present tests for the source of radiating high-energy electrons/positrons. We explore several models in the case of a pulsar population or dark matter annihilation as the source. These morphological signatures of these models are small behind the WMAP Galactic mask, but are testable and constrain the source models. We show that detailed measurements of the morphology may distinguish between the pulsar and dark matter interpretations as well as differentiate among different pulsar models and dark matter profile models individually. Specifically, we find that a zero central density Galactic pulsar population model is in tension with the observed WMAP haze. The Planck Observatory's greater sensitivity and expected smaller Galactic mask should potentially provide a robust signature of the WMAP haze as either a pulsar population or the dark matter.

We investigate analytically gravitational lensing by charged, stationary, axially symmetric Kerr-Sen dilaton-axion black hole in the weak deflection limit. Approximate solutions to the lightlike equations of motion are present up to and including third-order terms in M/b, a/b and ra/b, where M is the black hole mass, a is the angular momentum, ra=Q2/M, Q being the charge and b is the impact parameter of the light ray. We compute the positions of the two weak field images, the corresponding signed and absolute magnifications up to post-Newtonian order. It is shown that there are static post-Newtonian corrections to the signed magnification and their sum as well as to the critical curves, which are functions of the charge. The shift of the critical curves as a function of the lens angular momentum is found, and it is shown that they decrease slightly with the increase of the charge. The point-like caustics drift away from the optical axis and do not depend on the charge. All of the lensing quantities are compared to particular cases as Schwarzschild and Kerr black holes as well as the Gibbons-Maeda-Garfinkle-Horowitz-Strominger black hole.

We display some simple cosmological solutions of gravity theories with quadratic Ricci curvature terms added to the Einstein-Hilbert lagrangian which exhibit anisotropic inflation. The Hubble expansion rates are constant and unequal in three orthogonal directions. We describe the evolution of the simplest of these homogeneous and anisotropic cosmological models from its natural initial state and evaluate the deviations they will create from statistical isotropy in the fluctuations produced during a period of anisotropic inflation. The anisotropic inflation is not a late-time attractor in these models but the rate of approach to a final isotropic de Sitter state is slow and is conducive to the creation of observable anisotropic statistical effects in the microwave background. The statistical anisotropy would not be scale invariant and the level of statistical anisotropy will grow with scale.

The rate of e+e- pair creation by external electric field in the presence of an incident photon beam is calculated for the photon energy far below the threshold, w << m, and the field strength small as compared to the critical one, e E << m2. We find the pair production rate using a recently developed method based on calculation of the process in a thermal bath with subsequent identification of the contribution of single-photon states. We demonstrate that a non-trivial dependence on the ratio of the small parameters, wm/(e E), emerges in this approach from an essentially (semi)classical calculation.

In this work we study Podolsky electromagnetism in thermodynamic equilibrium. We show that a Podolsky mass-dependent modification to the Stefan-Boltzmann law is induced and we use experimental data to limit the possible values for this free parameter.

Since the energy momentum tensor of a magnetic field always contains a spin-2 component in its anisotropic stress, stochastic primordial magnetic field (PMF) in the early universe must generate stochastic gravitational wave (GW) background. This process will greatly affect the relic gravitational wave (RGW), which is one of major scientific goals of the laser interferometer GW detections. Recently, the fifth science (S5) run of laser interferometer gravitational-wave observatory (LIGO) gave a latest upper limit WGW < 6.9times;10-6 on the RGW background. Utilizing this upper limit, we derive new PMF Limits: for a scale of galactic cluster l = 1 Mpc, the amplitude of PMF, that produced by the electroweak phase transition (EPT), has to be weaker than Bl 4times;10-7 Gauss; for a scale of supercluster l = 100 Mpc, the amplitude of PMF has to be weaker than Bl 9times;10-11 Gauss. In this manner, GW observation has potential to make interesting contributions to the study of primordial magnetic field.

It is argued that the appropriate macroscopic description of half-BPS mesonic chiral operators in generic d=4 N=1 toric gauge theories is in terms of the geometric quantization of smooth horizonless configurations. The relevance of different ensemble macroscopic descriptions is emphasized : lorentzian vs euclidean configurations as (semiclassical) microstates vs saddle points in an euclidean path integral.