We use the boundary effective theory approach to thermal field theory in order to calculate the pressure of a system of massless scalar fields with quartic interaction. The method naturally separates the infrared physics, and is essentially nonperturbative. To lowest order, the main ingredient is the solution of the free Euler-Lagrange equation with nontrivial (time) boundary conditions. We derive a resummed pressure, which is in good agreement with recent calculations found in the literature, following a very direct and compact procedure.

We extend our previous studies of the neutrino fluxes expected from neutralino LSP annihilations inside the Sun to include variants of the minimal supersymmetric extension of the Standard Model (MSSM) with squark, slepton and gaugino masses constrained to be universal at the GUT scale, but allowing one or two nonuniversal supersymmetry breaking parameters contributing to the Higgs masses (NUHM1,2). As in the constrained MSSM (CMSSM) with universal Higgs masses, there are large regions of the NUHM parameter space where the LSP density inside the Sun is not in equilibrium, so that the annihilation rate may be far below the capture rate, and there are also large regions where the capture rate is not dominated by spin-dependent LSP-proton scattering. The spectra possible in the NUHM are qualitatively similar to those in the CMSSM. We calculate neutrino-induced muon fluxes above a threshold energy of 10 GeV, appropriate for the IceCube/DeepCore detector, for points where the NUHM yields the correct cosmological relic density for representative choices of the NUHM parameters. We find that the IceCube/DeepCore detector can probe regions of the NUHM parameter space in addition to analogues of the focus point strip and the tip of the coannihilation strip familiar from the CMSSM. These include regions with enhanced Higgsino-gaugino mixing in the LSP composition, that occurs where neutralino mass eigenstates cross over. On the other hand, rapid-annihilation funnel regions in general yield neutrino fluxes that are unobservably small.

We consider the black hole dynamical evolution in the framework of a Lorentz-violating spacetime endowed with a Schwarzchild-like momentum-dependent metric. Large deviations from the Hawking-Bekenstein predictions are obtained, depending on the values of the Lorentz-violating parameter $\lambda$ introduced. A nontrivial evolution comes out, following mainly from the existence of a nonvanishing minimum mass: for large Lorentz violations, most of the black hole evaporation takes place in the initial stage, which is then followed by a stationary stage (whose duration depends on the value of $\lambda$) where the mass does not change appreciably. Furthermore, for the final stage of evolution, our model predicts a sweet slow death of the black hole, whose “slowness” again depends on $\lambda$, in contrast with the violent final explosion predicted by the standard theory.

We study the exact spherically symmetric solutions in a class of Lorentz-breaking massive gravity theories, using the effective-theory approach where the graviton mass is generated by the interaction with a suitable set of Stückelberg fields. We find explicitly the exact black-hole solutions which generalizes the familiar Schwarzschild one, which shows a nonanalytic hair in the form of a powerlike term $r^{\gamma }$. For realistic self-gravitating bodies, we find interesting features, linked to the effective violation of the Gauss law: (i) the total gravitational mass appearing in the standard $1/r$ term gets a multiplicative renormalization proportional to the area of the body itself; (ii) the magnitude of the powerlike hairy correction is also linked to size of the body. The novel features can be ascribed to the presence of the Goldstones fluid turned on by matter inside the body; its equation of state approaching that of dark energy near the center. The Goldstones fluid also changes the matter equilibrium pressure, leading to an upper limit for the graviton mass, $m\lesssim {10}^{-28÷29}\mathrm{eV}$, derived from the largest stable gravitational bound states in the Universe.

We consider one-loop graviton corrections to Green’s scalar field functions in the de Sitter phase of an inflationary space-time, a topic relevant to the computation of cosmological observables beyond linear order. By embedding de Sitter space into an ultraviolet complete theory, such as M theory, we argue that the ultraviolet (UV) cutoff of the effective field theory should be taken to be fixed in physical coordinates, whereas the infrared (IR) cutoff is expanding as space expands. In this context, we demonstrate how to implement three different regularization schemes—the brute-force cutoff regularization, dimensional regularization and Pauli-Villars regularization—obtaining the same result for the scalar propagator if we use any of the three regularization schemes.

We show that equations governing pulsations of superfluid neutron stars can be split into two sets of weakly coupled equations, one describing the superfluid modes and another one, the normal modes. The coupling parameter $s$ is small, $|s|\sim 0.01–0.05$, for realistic equations of state. Already an approximation $s=0$ is sufficient to calculate the pulsation spectrum within the accuracy of a few percent. Our results indicate, in particular, that emission of gravitational waves from superfluid pulsation modes is suppressed in comparison to that from normal modes. The proposed approach allows to drastically simplify modeling of pulsations of superfluid neutron stars.

We update our analysis of $\rho$-$\omega$ mixing effects in the pion form factor to incorporate the recently published BABAR and KLOE $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ cross sections. Implications for $\tau$-decay-based standard model estimates of the leading order hadronic contribution to the muon anomalous magnetic moment, and for the extraction of the off-diagonal vector meson self-energy matrix element, ${\Pi }_{\rho \omega }(m_{\rho }^2)$, are discussed.

We construct a simple and natural supersymmetric model where the dominant Higgs decay is $h\to aa$ followed by $a\to gg$. In this case $m_h<m_Z$ is compatible with all experimental searches, completely eliminating the fine-tuning otherwise required to satisfy Higgs search limits. The model extends the minimal supersymmetric standard model with singlet Higgs fields as well as vectorlike colored particles that mediate the decay $a\to gg$. The $a$ is a pseudo-Nambu-Goldstone boson of a new global $U(1)$ symmetry, and can naturally have any mass from a few GeV to $m_h/2$. All interactions can be perturbative up to the GUT scale, and gauge coupling unification is preserved if the colored mediators come in complete GUT representations. In this case $a\to \gamma \gamma$ has a $\sim 1\%$ branching ratio, so $h\to gg\gamma \gamma$ may be observable. The colored particles that mediate the $a\to gg$ decay must be below the TeV scale, and can therefore be produced at the LHC. If these particles are stable on collider time scales, they will appear as $R$-hadrons, a signal visible in early LHC running. A smoking-gun signal that the stable colored particles are mediators of $h\to 4j$ is $R$-hadron production in association with an $a$. We show that this signal with $a\to \gamma \gamma$ is observable at the LHC with as little as $10{\mathrm{fb}}^{-1}$ of integrated luminosity. Observation of $R$-hadrons plus missing energy would show that the superpartner of the $R$-hadron is $R$-parity odd, and therefore not an ordinary quark or gluon.

We study the inert triplet models, in which the standard model is extended to have a new $SU(2{)}_L$ triplet scalar ($Y=0$ or 2) with an $Z_2$ symmetry. We show that the neutral component of the triplet can be a good dark matter candidate. In particular, for the hypercharge $Y=0$ triplet model, the WMAP data favors the region where the dark matter mass is around 5.5 TeV, which is also consistent with the direct detection experiments. In contrast, for the $Y=2$ model, although dark matter with its mass around 2.8 TeV is allowed by WMAP, it is excluded by the direct detection experiments because the spin-independent cross section is enhanced by the $Z$-mediated tree-level scattering process.

We present physical results obtained from simulations using $2+1$ flavors of domain wall quarks and the Iwasaki gauge action at two values of the lattice spacing $a$, [$a^{-1}=1.73(3)\mathrm{GeV}$ and $a^{-1}=2.28(3)\mathrm{GeV}$]. On the coarser lattice, with ${24}^3\times 64\times 16$ points (where the 16 corresponds to $L_s$, the extent of the 5th dimension inherent in the domain wall fermion formulation of QCD), the analysis of C. Allton et al. (RBC-UKQCD Collaboration), Phys. Rev. D 78 is extended to approximately twice the number of configurations. The ensembles on the finer ${32}^3\times 64\times 16$ lattice are new. We explain in detail how we use lattice data obtained at several values of the lattice spacing and for a range of quark masses in combined continuum-chiral fits in order to obtain results in the continuum limit and at physical quark masses. We implement this procedure for our data at two lattice spacings and with unitary pion masses in the approximate range 290–420 MeV (225–420 MeV for partially quenched pions). We use the masses of the $\pi$ and $K$ mesons and the $\Omega$ baryon to determine the physical quark masses and the values of the lattice spacing. While our data in the mass ranges above are consistent with the predictions of next-to-leading order SU(2) chiral perturbation theory, they are also consistent with a simple analytic ansatz leading to an inherent uncertainty in how best to perform the chiral extrapolation that we are reluctant to reduce with model-dependent assumptions about higher order corrections. In some cases, particularly for $f_{\pi }$, the pion leptonic decay constant, the uncertainty in the chiral extrapolation dominates the systematic error. Our main results include $f_{\pi }=124(2{)}_{\mathrm{stat}}(5{)}_{\mathrm{syst}}\mathrm{MeV}$, $f_K/f_{\pi }=1.204(7)(25)$ where $f_K$ is the kaon decay constant, $m_s^{\overline{\mathrm{MS}}}(2\mathrm{GeV})=(96.2\pm 2.7)\mathrm{MeV}$ and $m_{ud}^{\overline{\mathrm{MS}}}(2\mathrm{GeV})=(3.59\pm 0.21)\mathrm{MeV}$ ($m_s/m_{ud}=26.8\pm 1.4$) where $m_s$ and $m_{ud}$ are the mass of the strange quark and the average of the up and down quark masses, respectively, $[{\Sigma }^{\overline{\mathrm{MS}}}(2\mathrm{GeV}){]}^{1/3}=256(6)\mathrm{MeV}$, where $\Sigma$ is the chiral condensate, the Sommer scale $r_0=0.487(9)\mathrm{fm}$ and $r_1=0.333(9)\mathrm{fm}$.

We show how the linearized equations of motion of any dissipative current are determined by the analytical structure of the associated retarded Green’s function. If the singularity of Green’s function, which is nearest to the origin in the complex-frequency plane, is a simple pole on the imaginary frequency axis, the linearized equations of motion can be reduced to relaxation type equations for the dissipative currents. The value of the relaxation time is given by the inverse of this pole. We prove that, if the relaxation time is sent to zero, or equivalently, the pole to infinity, the dissipative currents approach the values given by the standard gradient expansion.

We report on a search for $CP$ violation in the decay $D^{\pm }\to K_S^0{\pi }^{\pm }$ using a data set corresponding to an integrated luminosity of $469{\mathrm{fb}}^{-1}$ collected with the BABAR detector at the PEP-II asymmetric energy $e^{+}{e}^{-}$ storage rings. The $CP$-violating decay rate asymmetry $A_{CP}$ is determined to be $(-0.44\pm 0.13(\mathrm{stat})\pm 0.10(\mathrm{syst}))\%$, consistent with zero at $2.7\sigma$ and with the standard model prediction of $(-0.332\pm 0.006)\%$. This is currently the most precise measurement of this parameter.

We present $f(\phi )(F_{\mu \nu }{)}^2$-type noncanonical and nonpolynomial interactions for an $N=1$ vector multiplet in three dimensions. We couple a Yang-Mills multiplet $(A_{\mu }{}^I,{\lambda }^I)$ to a scalar multiplet $(\phi ,\chi )$, where $\phi$ appears in the arbitrary scalar function $f(\phi )$ in the coupling $\alpha f(\phi )(F_{\mu \nu }{}^I{)}^2$. Supersymmetric Chern-Simons terms for the vector multiplet and a potential term for the scalar multiplet can be also added. We first give the component Lagrangian, and we give its superspace reformulation. We also give exact solutions for the vector and scalar fields in the Abelian case with a finite total energy.

Thin-shell wormholes are constructed starting from the exotic branch of the Wiltshire spherically symmetric solution of Einstein-Gauss-Bonnet gravity. The energy-momentum tensor of the shell is studied, and it is shown that configurations supported by matter satisfying the energy conditions exist for certain values of the parameters. Differing from the previous result associated with the normal branch of the Wiltshire solution, this is achieved for small positive values of the Gauss-Bonnet parameter and for vanishing charge.

We combine the unitarity method with the six-dimensional helicity formalism of Cheung and O’Connell to construct loop-level scattering amplitudes. As a first example, we construct dimensionally regularized QCD one-loop four-point amplitudes. As a nontrivial multiloop example, we confirm that the recently constructed four-loop four-point amplitude of $\mathcal{N}=4$ super-Yang-Mills theory, including nonplanar contributions, is valid for dimensions $D\le 6$. We comment on the connection of our approach to the recently discussed Higgs infrared regulator and on dual conformal properties in six dimensions.

We construct a free fermion and matrix model representation of refined Bogomol’nyi-Prasad-Sommerfeld generating functions of D2 and D0 branes bound to a single D6 brane, in a class of toric manifolds without compact four-cycles. In appropriate limit we obtain a matrix model representation of refined topological string amplitudes. We consider a few explicit examples which include a matrix model for the refined resolved conifold, or equivalently five-dimensional $U(1)$ gauge theory, as well as a matrix representation of the refined MacMahon function. Matrix models which we construct have ordinary unitary measure, while their potentials are modified to incorporate the effect of the refinement.

We obtain an explicit expression for the center-of-mass (CM) energy of two colliding general geodesic massive and massless particles at any spacetime point around a Kerr black hole. Applying this, we show that the CM energy can be arbitrarily high only in the limit to the horizon and then derive a formula for the CM energy of two general geodesic particles colliding near the horizon in terms of the conserved quantities of each particle and the polar angle. We present the necessary and sufficient condition for the CM energy to be arbitrarily high in terms of the conserved quantities of each particle. To have an arbitrarily high CM energy, the angular momentum of either of the two particles must be fine-tuned to the critical value $L_i={\Omega }_H^{-1}{E}_i$, where ${\Omega }_H$ is the angular velocity of the horizon and $E_i$ and $L_i$ are the energy and angular momentum of particle $i(=1,2)$, respectively. We show that, in the direct collision scenario, the collision with an arbitrarily high CM energy can occur near the horizon of maximally rotating black holes not only at the equator but also on a belt centered at the equator. This belt lies between latitudes $\pm \mathrm{acos}(\sqrt{3}-1)\simeq \pm 42.94°$. This is also true in the scenario through the collision of a last stable orbit particle.

The properties of magnetized plasmas are always investigated under the hypothesis that the relativistic inhomogeneities stemming from the fluid sources and from the geometry itself are sufficiently small to allow for a perturbative description prior to photon decoupling. The latter assumption is hereby relaxed and predecoupling plasmas are described within a suitable expansion where the inhomogeneities are treated to a given order in the spatial gradients. It is argued that the (general relativistic) gradient expansion shares the same features of the drift approximation, customarily employed in the description of cold plasmas, so that the two schemes are physically complementary in the large-scale limit and for the low-frequency branch of the spectrum of plasma modes. The two-fluid description, as well as the magnetohydrodynamical reduction, is derived and studied in the presence of the spatial gradients of the geometry. Various solutions of the coupled system of evolution equations in the anti-Newtonian regime and in the quasi-isotropic approximation are presented. The relation of this analysis to the so-called separate universe paradigm is outlined. The evolution of the magnetized curvature perturbations in the nonlinear regime is addressed for the magnetized adiabatic mode in the plasma frame.

In this paper we discuss the excess gamma rays from the Galactic center, the WMAP haze and the CoGeNT and DAMA results in WIMPless models. At the same time we also investigate the low energy constraints from the anomalous magnetic moment of leptons and from some lepton flavor violating decays. It is found that, for scalar or vector WIMPless dark matter, neither the WMAP haze nor the CoGeNT and DAMA observations could be explained simultaneously with the excess gamma rays from the Galactic center. As to fermion WIMPless dark matter, it is only marginally possible to accommodate the CoGeNT and DAMA results with the excess gamma rays from the Galactic center with vector connector fields. On the other hand, only scalar connector fields could interpret the WMAP haze concerning the constraints of anomalous magnetic moment of leptons. Furthermore, if there is only one connector field for all the charged leptons, some lepton flavor violating decays could happen with too large branching ratios severely violating the experimental bounds.