We consider the decay of metastable walls and strings populated by additional degrees of freedom. The examples involve the decay of an axion wall in an external magnetic field, pionic walls, and metastable walls in dense QCD. It is shown that the induced fermions escape from the wall during the decay process, providing an example of the chiral magnetic effect. An absolute stabilization of metastable and unstable walls in a large magnetic field is found. A possible higher-dimensional generalization of the chiral magnetic effect is mentioned.

We generalize recent analysis of the dynamics of point particle in Hořava-Lifshitz background to the case of string probe when we replace the Hamiltonian constraint of the Polyakov string with the constraint that breaks Lorentz invariance of target space-time. Then, we find corresponding Lagrangian and argue that the world sheet theory is invariant under foliation-preserving diffeomorphism. Finally, we discuss the Hamiltonian dynamics and show that this is well defined on condition that the world sheet lapse function obeys the projectability condition.

In a landscape of compactifications with different numbers of macroscopic dimensions, it is possible that our Universe has nucleated from a vacuum where some of our four large dimensions were compact while other, now compact, directions were macroscopic. From our perspective, this shapeshifting can be perceived as an anisotropic background spacetime. As an example, we present a model where our Universe emerged from a tunneling event which involves the decompactification of two dimensions compactified on the two-sphere. In this case, our Universe is of the Kantowski-Sachs type and therefore homogeneous and anisotropic. We study the deviations from statistical isotropy of the cosmic microwave background induced by the anisotropic curvature, with particular attention to the anomalies. The model predicts a quadrupolar power asymmetry with the same sign and acoustic oscillations as found by the Wilkinson Microwave Anisotropy Probe. The amplitude of the effect is however too small given the current estimated bound on anisotropic curvature derived from the quadrupole.

We derive the $U$-duality charge orbits, as well as the related moduli spaces, of “large” and “small” extremal black holes in nonmaximal ungauged Maxwell-Einstein supergravities with symmetric scalar manifolds in $d=5$ space-time dimensions. The stabilizer groups of the various classes of orbits are obtained by determining and solving suitable $U$-invariant sets of constraints, both in “bare” and “dressed” charge bases, with various methods. After a general treatment of attractors in real special geometry (also considering nonsymmetric cases), the $\mathcal{N}=2$ “magic” theories, as well as the $\mathcal{N}=2$ Jordan symmetric sequence, are analyzed in detail. Finally, the half-maximal ($\mathcal{N}=4$) matter-coupled supergravity is also studied in this context.

We apply the postquasistatic approximation, an iterative method for the evolution of self-gravitating spheres of matter, to study the evolution of dissipative and electrically charged distributions in general relativity. The numerical implementation of our approach leads to a solver which is globally second-order convergent. We evolve nonadiabatic distributions assuming an equation of state that accounts for the anisotropy induced by the electric charge. Dissipation is described by streaming-out or diffusion approximations. We match the interior solution, in noncomoving coordinates, with the Vaidya-Reissner-Nordström exterior solution. Two models are considered: (i) a Schwarzschild-like shell in the diffusion limit; and (ii) a Schwarzschild-like interior in the free-streaming limit. These toy models tell us something about the nature of the dissipative and electrically charged collapse. Diffusion stabilizes the gravitational collapse producing a spherical shell whose contraction is halted in a short characteristic hydrodynamic time. The streaming-out radiation provides a more efficient mechanism for emission of energy, redistributing the electric charge on the whole sphere, while the distribution collapses indefinitely with a longer hydrodynamic time scale.

We place new constraints on the primordial local non-Gaussianity parameter $f_{\mathrm{NL}}$ using recent cosmic microwave background anisotropy and galaxy clustering data. We model the galaxy power spectrum according to the halo model, accounting for a scale-dependent bias correction proportional to $f_{\mathrm{NL}}/k^2$. We first constrain $f_{\mathrm{NL}}$ in a full 13 parameters analysis that includes 5 parameters of the halo model and 7 cosmological parameters. Using the WMAP7 CMB data and the SDSS DR4 galaxy power spectrum, we find $f_{\mathrm{NL}}={171}_{-139}^{+140}$ at 68% C.L. and $-69<f_{\mathrm{NL}}<+492$ at 95% C.L. We discuss the degeneracies between $f_{\mathrm{NL}}$ and other cosmological parameters. Including SN-Ia data and priors on $H_0$ from Hubble Space Telescope observations we find a stronger bound: $-35<f_{\mathrm{NL}}<+479$ at 95%. We also fit the more recent SDSS DR7 halo power spectrum data finding, for a $\Lambda \mathrm{CDM}+f_{\mathrm{NL}}$ model, $f_{\mathrm{NL}}=-93\pm 128$ at 68% C.L. and $-327<f_{\mathrm{NL}}<+177$ at 95% C.L. We finally forecast the constraints on $f_{\mathrm{NL}}$ from future surveys as EUCLID and from CMB missions as Planck showing that their combined analysis could detect $f_{\mathrm{NL}}\sim 5$.

Using a Thomas-Fermi model, we calculate the structure of the electrosphere of the quark antimatter nuggets postulated to comprise much of the dark matter. This provides a single self-consistent density profile from ultrarelativistic densities to the nonrelativistic Boltzmann regime that we use to present microscopically justified calculations of several properties of the nuggets, including their net charge, and the ratio of MeV to 511 keV emissions from electron annihilation. We find that the calculated parameters agree with previous phenomenological estimates based on the observational supposition that the nuggets are a source of several unexplained diffuse emissions from the Galaxy. As no phenomenological parameters are required to describe these observations, the calculation provides another nontrivial verification of the dark-matter proposal. The structure of the electrosphere is quite general and will also be valid at the surface of strange-quark stars, should they exist.

We study the effect of dark matter (DM) particles in the Sun, focusing, in particular, on the possible reduction of the solar neutrinos flux due to the energy carried away by DM particles from the innermost regions of the Sun, and to the consequent reduction of the temperature of the solar core. We find that in the very low-mass range between 4 and 10 GeV, recently advocated to explain the findings of the DAMA and CoGent experiments, the effects on neutrino fluxes are detectable only for DM models with a very small, or vanishing, self-annihilation cross section, such as the so-called asymmetric DM models, and we study the combination of DM masses and spin-dependent cross sections which can be excluded with current solar neutrino data. Finally, we revisit the recent claim that DM models with large self-interacting cross sections can lead to a modification of the position of the convective zone, alleviating or solving the solar composition problem. We show that when the “geometric” upper limit on the capture rate is correctly taken into account, the effects of DM are reduced by orders of magnitude, and the position of the convective zone remains unchanged.

The requirements for stability of a Lorentz violating theory are analyzed. In particular we conclude that Einstein-aether theory can be stable when its modes have any phase velocity, rather than only the speed of light as was argued in a recent paper.

We propose a nonuniversal $U(1{)}_F^{\prime }$ symmetry combined with the minimal supersymmetric standard model. All anomaly cancellation conditions are satisfied without exotic fields other than three right-handed neutrinos. Because our model allows all three generations of chiral superfields to have different $U(1{)}_F^{\prime }$ charges, upon the breaking of the $U(1{)}_F^{\prime }$ symmetry at a low scale, realistic masses and mixing angles in both the quark and lepton sectors are obtained. In our model, neutrinos are predicted to be Dirac fermions and their mass ordering is of the inverted hierarchy type. The $U(1{)}_F^{\prime }$ charges of the chiral superfields also naturally suppress the $\mu$-term and automatically forbid baryon number and lepton number violating operators. While all flavor-changing neutral current constraints in the down quark and charged-lepton sectors can be satisfied, we find that the constraint from $D^0-{\overline{D}}^0$ turns out to be much more stringent than the constraints from the precision electroweak data.

We propose a method to control the number of species of lattice fermions, which yields new classes of minimally doubled lattice fermions. We show it is possible to control the number of species by handling $O(a)$ Wilson-term-like corrections in fermion actions, which we will term “twisted-ordering method”. Using this method we obtain new minimally doubled actions with one exact chiral symmetry and exact locality. We classify the known minimally doubled fermions into two types based on the locations of the propagator poles in the Brillouin zone.

Generalized parton distributions of the nucleon are accessed via exclusive leptoproduction of the real photon. While earlier analytical considerations of phenomenological observables were restricted to twist-three accuracy, i.e., taking into account only terms suppressed by a single power of the hard scale, in the present study we revisit this differential cross section within the helicity formalism and restore power-suppressed effects stemming from the process kinematics exactly. We restrict ourselves to the phenomenologically important case of lepton scattering off a longitudinally polarized nucleon, where the photon flips its helicity at most by one unit.

In this paper the cross sections of the processes $e^{+}{e}^{-}\to H+\gamma$, $H={\eta }_c$, ${\eta }_c^{\prime }$, ${\chi }_{c0}$, ${\chi }_{c1}$, ${\chi }_{c2}$ are calculated. The calculation is carried out at the leading twist approximation of the light cone formalism. Within this approach the leading logarithmic radiative and relativistic corrections to the amplitudes are resummed. For the processes $e^{+}{e}^{-}\to {\eta }_c$, ${\eta }_c^{\prime }+\gamma$ one-loop radiative corrections are taken into account. It is also shown that one-loop leading logarithmic radiative corrections calculated within the light cone formalism for the processes under study coincide with that obtained by direct calculations of one-loop diagrams within nonrelativistic QCD.

Using the entire sample of $467\times {10}^6$ ${\rm Y}(4S)\to B\overline{B}$ decays collected with the BABAR detector at the PEP-II asymmetric-energy $B$ factory at the SLAC National Accelerator Laboratory, we perform an analysis of $B^{\pm }\to D{K}^{\pm }$ decays, using decay modes in which the neutral $D$ meson decays to either $CP$-eigenstates or non-$CP$-eigenstates. We measure the partial decay rate charge asymmetries for $CP$-even and $CP$-odd $D$ final states to be $A_{CP+}=0.25\pm 0.06\pm 0.02$ and $A_{CP-}=-0.09\pm 0.07\pm 0.02$, respectively, where the first error is the statistical and the second is the systematic uncertainty. The parameter $A_{CP+}$ is different from zero with a significance of 3.6 standard deviations, constituting evidence for direct $CP$ violation. We also measure the ratios of the charged-averaged $B$ partial decay rates in $CP$ and non-$CP$ decays, $R_{CP+}=1.18\pm 0.09\pm 0.05$ and $R_{CP-}=1.07\pm 0.08\pm 0.04$. We infer frequentist confidence intervals for the angle $\gamma$ of the unitarity triangle, for the strong phase difference ${\delta }_B$, and for the amplitude ratio $r_B$, which are related to the $B^{-}\to D{K}^{-}$ decay amplitude by $r_B{e}^{i({\delta }_B-\gamma )}=A(B^{-}\to {\overline{D}}^0{K}^{-})/A(B^{-}\to D^0{K}^{-})$. Including statistical and systematic uncertainties, we obtain $0.24<r_B<0.45$ ($0.06<r_B<0.51$) and, modulo 180°, $11.3°<\gamma <22.7°$ or $80.8°<\gamma <99.2°$ or $157.3°<\gamma <168.7°$ ($7.0°<\gamma <173.0°$) at the 68% (95%) confidence level.

We formulate a duality-symmetric $N=1$ supersymmetric Yang-Mills theory in three dimensions. Our field content is $(A_{\mu }{}^I,{\lambda }^I,{\phi }^I)$, where the index $I$ is for the adjoint representation of an arbitrary gauge group $G$. Our Hodge duality symmetry is $F_{\mu \nu }{}^I=+ϵ_{\mu \nu }{}^{\rho }{D}_{\rho }{\phi }^I$. Because of this relationship, the presence of two physical fields $A_{\mu }{}^I$ and ${\phi }^I$ within the same $N=1$ supermultiplet poses no problem. We can couple this multiplet to another vector multiplet $(C_{\mu }{}^I,{\chi }^I;B_{\mu \nu }{}^I)$ with $1+1$ physical degrees of freedom modulo $\dim G$. Thanks to peculiar couplings and supersymmetry, the usual problem with an extra vector field in a nontrivial representation does not arise in our system.

In the present paper we show that for a low frequency limit the wave equation of a massless scalar field in the background of nonextremal charged rotating black holes in five-dimensional minimal gauged and ungauged supergravity can be written as the Casimir of an $SL(2,R)$ symmetry. Our result shows that the entropy of the black hole is reproduced by the Cardy formula. Also the absorption cross section is consistent with the finite temperature absorption cross section for a two-dimensional conformal field theory.

We study the main properties of the one-loop vacuum polarization function (${\Pi }_{\mu \nu }$) for massless spinor $QE{D}_4$ in a slab, namely, with fields defined on $\mathcal{M}\subset {\mathbb{R}}^{3+1}$, such that $\mathcal{M}=\{(x_0,\dots ,x_3)|0\le x_3\le ϵ\}$, and baglike boundary conditions on the boundary. We evaluate the induced charge density and current due to an external constant electric field normal to the boundary; we also study the effective action for a purely transverse field, identifying its $ϵ$-dependent contribution.

The gravitational waves and energy radiation from a spinning compact object with stellar mass in a circular orbit in the equatorial plane of a supermassive Kerr black hole are investigated in this paper. The effect of how the spin acts on energy and angular moment fluxes is discussed in detail. The calculation results indicate that the spin of a small body should be considered in waveform-template production for the upcoming gravitational wave detections. It is clear that when the direction of spin axes is the same as the orbitally angular momentum (“positive” spin), spin can decrease the energy fluxes which radiate to infinity. For antidirection spin (“negative”), the energy fluxes to infinity can be enlarged. And the relations between fluxes (both infinity and horizon) and spin look like quadratic functions. From frequency shift due to spin, we estimate the wave-phase accumulation during the inspiraling process of the particle. We find that the time of particle inspiral into the black hole is longer for positive spin and shorter for negative compared with the nonspinning particle. Especially, for extreme spin value, the energy radiation near the horizon of the extreme Kerr black hole is much more than that for the nonspinning one. And consequently, the maximum binging energy of the extreme spinning particle is much larger than that of the nonspinning particle.

We complete the quantization of the vacuum Bianchi I model within the framework of loop quantum cosmology adopting a new improved dynamics scheme put forward recently. In addition, we revisit the hybrid quantization of the Gowdy $T^3$ cosmologies with linear polarization using that scheme, proving with rigor some steps that remained unconcluded. The family of Gowdy $T^3$ cosmologies is an inhomogeneous model whose subset of homogeneous solutions is given precisely by the vacuum Bianchi I model. Our hybrid approach combines the new loop quantum cosmology description of this homogeneous sector with a Fock quantization of the inhomogeneities. Both in the Bianchi I model and in the Gowdy model the Hamiltonian constraint provides an evolution equation with respect to the volume of the Bianchi I universe, which is a discrete variable with a strictly positive minimum. We show that, in vacuo, this evolution is well defined inasmuch as the associated initial value problem is well posed: physical solutions are completely determined by the data on the initial section of constant Bianchi I volume. This fact allows us first to carry out to completion the quantization of the vacuum Bianchi I model which had not yet been achieved and then to confirm the feasibility of the hybrid procedure when the homogeneous sector is quantized with the new improved dynamics scheme.

Within the effective average action approach to quantum gravity, we recover the low-energy effective action as derived in the effective field theory framework by studying the flow of possibly nonlocal form factors that appear in the curvature expansion of the effective average action. We restrict to the one-loop flow where progress can be made with the aid of the nonlocal heat kernel expansion. We discuss the possible physical implications of the scale-dependent low-energy effective action through the analysis of the quantum corrections to the Newtonian potential.