Separation of the $B$ component of a cosmic microwave background (CMB) polarization map from the much larger $E$ component is an essential step in CMB polarimetry. For a map with incomplete sky coverage, this separation is necessarily hampered by the presence of ambiguous modes which could be either $E$ or $B$ modes. I present an efficient pixel-space algorithm for removing the ambiguous modes and separating the map into pure $E$ and $B$ components. The method, which works for arbitrary geometries, does not involve generating a complete basis of such modes and scales the cube of the number of pixels on the boundary of the map.

We propose a new method to search for heavy nuclei sources, on top of background, in the Ultra-High Energy Cosmic Ray data. We apply this method to the 69 events recently published by the Pierre Auger Collaboration [P. Abreu et al. (Pierre Auger Observatory Collaboration), Astropart. Phys. 34, 314 (2010).] and find a tail of events for which it reconstructs the source at a few degrees from the Virgo galaxy cluster. The reconstructed source is located at $\simeq 8.5°$ from M87. The probability to have such a cluster of events in some random background and reconstruct the source position in any direction of the sky is about $7\times {10}^{-3}$. The probability to reconstruct the source at less than 10° from M87 in a data set already containing such a cluster of events is about $4\times {10}^{-3}$. This may be a hint at the Virgo cluster as a bright ultrahigh energy nuclei source. We investigate the ability of current and future experiments to validate or rule out this possibility, and discuss several alternative solutions which could explain the existing anisotropy in the Auger data.

In calculations of the hyperfine splitting in charmonium, the contributions of the disconnected diagrams are considered small and are typically ignored. We aim to estimate nonperturbatively the size of the resulting correction, which may eventually be needed in high precision calculations of the charmonium spectrum. We study this problem in the quenched and unquenched QCD cases. On dynamical ensembles the disconnected charmonium propagators contain light modes which complicate the extraction of the signal at large distances. In the fully quenched case, where there are no such light modes, the interpretation of the signal is simplified. We present results from lattices with $a\approx 0.09\mathrm{fm}$ and $a\approx 0.06\mathrm{fm}$.

We consider a scenario (supported by some lattice results) in which a $U(1)$-breaking condensate survives across the chiral transition in QCD. This scenario has important consequences for the pseudoscalar-meson sector, which can be studied using an effective Lagrangian model. In particular, generalizing the results obtained in two previous papers, where the effects on the radiative decays $\eta$, ${\eta }^{\prime }\to \gamma \gamma$ were studied, in this paper we study the effects of the $U(1)$ chiral condensate on the strong decays of the “light” pseudoscalar mesons, i.e., $\eta$, ${\eta }^{\prime }\to 3{\pi }^0$; $\eta$, ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{\pi }^0$; ${\eta }^{\prime }\to \eta {\pi }^0{\pi }^0$; ${\eta }^{\prime }\to \eta {\pi }^{+}{\pi }^{-}$; and also on the strong decays of an exotic (“heavy”) $SU(3)$-singlet pseudoscalar state ${\eta }_X$, predicted by the model.

The forward-backward asymmetry in top-pair production that was observed in 2008 gets a boost in a recent CDF publication. Not only has the forward-backward asymmetry been further confirmed, but also distributional preferences are shown. Strikingly, the forward-backward asymmetry is the most sizable in the large $M_{t\overline{t}}$ invariant mass region and in the large rapidity difference $|\Delta y|$ region. Here we used our previously proposed $t$-channel exchanged $W^{\prime }$ boson to explain the new observations. We show that a new particle exchanged in the $t$ channel generically gives rise to such observations. Furthermore, we show that the proposed $W^{\prime }$ can be directly produced in association with a top quark at the Tevatron and the LHC. We perform a signal-background analysis and show that such a $W^{\prime }$ is readily observed at the Tevatron with a $10{\mathrm{fb}}^{-1}$ luminosity and at the LHC-7 with just a $100{\mathrm{pb}}^{-1}$ luminosity.

We set up a new, flexible approach for the tensor reduction of one-loop Feynman integrals. The 5-point tensor integrals up to rank $R=5$ are expressed by 4-point tensor integrals of rank $R-1$, such that the appearance of the inverse 5-point Gram determinant is avoided. The 4-point tensor coefficients are represented in terms of 4-point integrals, defined in $d$ dimensions, $4-2ϵ\le d\le 4-2ϵ+2(R-1)$, with higher powers of the propagators. They can be further reduced to expressions which stay free of the inverse 4-point Gram determinants but contain higher-dimensional 4-point integrals with only the first power of scalar propagators, plus 3-point tensor coefficients. A direct evaluation of the higher-dimensional 4-point functions would avoid the appearance of inverse powers of the Gram determinants completely. The simplest approach, however, is to apply here dimensional recurrence relations in order to reduce them to the familiar 2- to 4-point functions in generic dimension $d=4-2\epsilon$, introducing thereby coefficients with inverse 4-point Gram determinants up to power $R$ for tensors of rank $R$. For small or vanishing Gram determinants—where this reduction is not applicable—we use analytic expansions in positive powers of the Gram determinants. Improving the convergence of the expansions substantially with Padé approximants we close up to the evaluation of the 4-point tensor coefficients for larger Gram determinants. Finally, some relations are discussed which may be useful for analytic simplifications of Feynman diagrams.

The solution of Einstein’s field equations with the energy-momentum tensor of a massless scalar field is known as the Fisher solution. It is well known that this solution has a naked singularity due to the “charge” $\Sigma$ of the massless scalar field. Here I obtain the radial null geodesic of the Fisher solution and use it to confirm that there is no black hole. In addition, I use the parametrized post-Newtonian formalism to show that the Fisher spacetime predicts the same effects on solar-system experiments as the Schwarzschild one does, as long as we impose a limit on $\Sigma$. I show that this limit is not a strong constraint and we can even take values of $\Sigma$ bigger than $M$. By using the exact formula of the redshift and some assumptions, I evaluate this limit for the experiment of Pound and Snider [Phys. Rev. 140, B788 (1965)]. It turns out that this limit is $\Sigma <5.8\times {10}^3\mathrm{m}$.

Using a five-dimensional anti-de Sitter (AdS) soliton in an Einstein-Yang-Mills theory with $SU(2)$ gauge group, we study $p$-wave holographic insulator/superconductor phase transition. To explore the phase structure of the model, we consider the system in the probe limit as well as fully back-reacted solutions. We will also study the zero temperature limit of the $p$-wave holographic superconductor in four dimensions.

We present time-dependent solutions in the higher-dimensional gravity which are related to supergravity in the particular cases. Here, we consider $p$-branes with a cosmological constant and the intersections of two and more branes. The dynamical description of $p$-branes can be naturally obtained as the extension of static solutions. In the presence of a cosmological constant, we find accelerating solutions if the dilaton is not dynamical. In the case of intersecting branes, the field equations normally indicate that time-dependent solutions in supergravity can be found if only one harmonic function in the metric depends on time. However, if the special relation between dilaton couplings to antisymmetric tensor field strengths is satisfied, one can find a new class of solutions where all harmonic functions depend on time. We then apply our new solutions to study cosmology, with and without performing compactifications.

We study the 3d Ising universality class using the functional renormalization group. With the help of background fields and a derivative expansion up to fourth order we compute the leading index, the subleading symmetric and antisymmetric corrections to scaling, the anomalous dimension, the scaling solution, and the eigenperturbations at criticality. We also study the cross correlations of scaling exponents, their dependence on dimensionality, and the numerical convergence of the derivative expansion. Collecting all available data from functional renormalization group studies to date, we estimate that systematic errors are in good agreement with findings from Monte Carlo simulations, $ϵ$-expansion techniques, and resummed perturbation theory.

We solve the vacuum Einstein’s field equations with the cosmological constant in space-times admitting three-parameter group of isometries with two-dimensional spacelike orbits. The general exact solutions, which are represented in the advanced and retarded null coordinates, have two arbitrary functions due to the freedom of choosing null coordinates. In the thin-wall approximation, the Israel’s junction conditions yield one constraint equation on these two functions in spherical, planar, and hyperbolic domain wall space-times with reflection symmetry. The remain freedom of choosing coordinates is completely fixed by requiring that, when the surface energy density ${\sigma }_0$ of domain walls vanishes, the metric solutions will return to some well-known solutions. It leads us to find a planar domain wall solution, which is conformally flat, in the de Sitter universe.

We study the gravitational wave emission of three compact objects using post-Newtonian (PN) equations of motion derived from the Arnowitt-Deser-Misner-Hamiltonian formulation, where we include (for the first time in this context) terms up to 2.5 PN order. We perform numerical simulations of a hierarchical configuration of three compact bodies in which a binary system is perturbed by a third, lighter body initially far away from the binary. The relative importance of the different PN orders is examined. We compute the waveform in the linear regime considering mass quadrupole, current quadrupole and mass octupole contributions. Performing a spherical harmonic decomposition of the waveforms we find that from the $l=3$ modes it is possible to extract information about the third body, in particular, the period, eccentricity of its orbit, and the inclination angle between the inner and outer binary orbits.

Considering the general quantum corrections to the area law of black hole entropy and adopting the viewpoint that gravity interprets as an entropic force, we derive the modified forms of Modified Newtonian dynamics (MOND) theory of gravitation and Einstein field equations. As two special cases we study the logarithmic and power-law corrections to entropy and find the explicit form of the obtained modified equations.

The combined effects of the Lorentz-symmetry violating Chern-Simons and Ricci-Cotton actions are investigated for the Einstein-Hilbert gravity in the second-order formalism modified by higher derivative terms, and their consequences on the spectrum of excitations are analyzed. We follow the lines of previous works and build up an orthonormal basis of projector-like operators for the degrees of freedom, rather than for the spin modes of the fields. With this new basis, the attainment of the propagators is remarkably simplified and the identification of the physical and unphysical modes becomes more immediate. Our conclusion is that the only tachyon- and ghost-free model is the Einstein-Hilbert action added up by the Chern-Simons term with a timelike vector of the type $v^{\mu }=(\mu ,\overrightarrow{0})$. Spectral consistency imposes that the Ricci-Cotton term must be switched off. We then infer that gravity with Lorentz-symmetry violation imposes a drastically different constraint on the background if compared to ordinary gauge theories whenever conditions for the suppression of tachyons and ghosts are imposed.

The single diffractive production of the standard model Higgs boson is computed using the diffractive factorization formalism, taking into account a parametrization for the Pomeron structure function provided by the H1 Collaboration. We compute the cross sections at next-to-leading order accuracy for the gluon fusion process, which includes QCD and electroweak (EW) corrections. The gap survival probability ($⟨|S{|}^2⟩$) is also introduced to account for the rescattering corrections due to spectator particles present in the interaction, and to this end we compare two different models for the survival factor. The diffractive ratios are predicted for proton-proton collisions at the Tevatron and the LHC for the Higgs boson mass of $M_H=120\mathrm{GeV}$. Therefore, our results provide updated estimations for the diffractive ratios of the single diffractive production of the Higgs boson in the Tevatron and LHC kinematical regimes.

We present Stückelberg mechanisms for tensor multiplets coupled to supergravity in four dimensions (4D), six dimensions (6D), and three dimensions (3D). For $N=1$ supergravity in 4D, our field content is $(e_{\mu }{}^m,{\psi }_{\mu })$, $(B_{\mu \nu },\chi ,\phi )$ and $(A_{\mu },\lambda )$, respectively, for the supergravity, tensor, and vector multiplets. In our Stückelberg mechanism, the Abelian vector field $A_{\mu }$ is absorbed into the longitudinal component of the tensor $B_{\mu \nu }$, which becomes massive. The field strength $F=dA$ of $A$ is replaced by $\mathcal{F}\equiv F+mB$, where $m$ is a coupling constant with the dimension of mass. In 6D, we utilize the so-called dual version for $N=2$ supergravity, in order to avoid the obstruction caused by the Chern-Simons term $F\wedge A$ in the $B$-field strength $G$. Instead of the $F\wedge A$-term in $G$, the 6D Lagrangian has a peculiar topological and cubic interaction term proportional to $m^{-1}\mathcal{F}\wedge \mathcal{F}\wedge \mathcal{F}$. In 3D, we also show that a similar mechanism works for $N=1$ supergravity. Interestingly, the basic structure is parallel to the 4D case, except that the originally nonpropagating field $B$ starts propagating, after absorbing the $A$-field. We also show a possible compactification of 6D theory on ${\mathrm{AdS}}_3\times {\mathrm{S}}^3$.

We consider a relativistic plasma containing charged chiral fermions in an external magnetic field, e.g. a chirally symmetric quark-gluon plasma created in relativistic heavy ion collisions. We show that triangle anomalies imply the existence of a new type of collective gapless excitation in this system that stems from the coupling between the density waves of the electric and chiral charges; we call it “the chiral magnetic wave” (CMW). The CMW exists even in a neutral plasma, i.e. in the absence of the axial and vector chemical potentials. We demonstrate the existence of CMW and study its properties using three different approaches: i) relativistic magnetohydrodynamics; ii) dimensional reduction to ($1+1$) Sine-Gordon model, appropriate in a strong magnetic field; and iii) holographic QCD (Sakai-Sugimoto model), appropriate at strong coupling. We also briefly discuss the phenomenological implications of the CMW for heavy ion collisions.

The sensitivity of the black hole spectrum when introducing short distance dispersion is studied in the context of atomic Bose condensates. By considering flows characterized by several length scales, we show that, while the spectrum remains remarkably Planckian, the temperature is no longer fixed by the surface gravity. Rather it is determined by the average of the flow gradient across the horizon over an interval fixed by the healing length and the surface gravity, as if the horizon were broadened. This remains valid as long as the flow does not induce nonadiabatic effects that produce oscillations or some parametric amplification of the flux.

In this note we study the linear dynamics of scalar graviton in a de Sitter background in the infrared limit of the healthy extension of Hořava-Lifshitz gravity with the dynamical critical exponent $z=3$. Both our analytical and numerical results show that the nonzero Fourier modes of scalar graviton oscillate with an exponentially damping amplitude on the subhorizon scale, while on the superhorizon scale, the phases are frozen and they approach to some asymptotic values. In addition, as the case of the nonzero modes on superhorizon scale, the zero mode also initially decays exponentially and then approaches to an asymptotic constant value.