The Kerr/CFT correspondence is a holographic duality between a two dimensional chiral conformal field theory (CFT) and the very near horizon limit of an extremal black hole, which includes an ${\mathrm{AdS}}_2$ structure. To understand the dual chiral ${\mathrm{CFT}}_2$, we apply the Kerr/CFT correspondence to a certain class of black holes embedded in string theory, which include the D1-D5-P and the Breckenridge-Myers-Peet-Vafa black holes, and obtain the correct entropies for the black holes microscopically. These have an ${\mathrm{AdS}}_3$ structure in the near horizon geometry and an ${\mathrm{AdS}}_2$ structure in the very near horizon geometry. We identified one of the two Virasoro symmetries in the nonchiral ${\mathrm{CFT}}_2$ dual to the ${\mathrm{AdS}}_3$, i.e., in the ${\mathrm{AdS}}_3/{\mathrm{CFT}}_2$, with the Virasoro symmetry in the chiral ${\mathrm{CFT}}_2$ dual to the ${\mathrm{AdS}}_2$, i.e., in the Kerr/CFT correspondence. We also discuss a way to understand the chiral ${\mathrm{CFT}}_2$ dual to generic extremal black holes. A kind of universality for the very near horizon geometries of extremal black holes will be important for the validity of the Kerr/CFT correspondence. Based on this analysis, we propose that the Kerr/CFT correspondence can be understood as a decoupling limit in which only the ground states remain.

We investigate the Sakai-Sugimoto model at nonzero baryon chemical potential in a background magnetic field both in the confined phase and in the deconfined phase with restored chiral symmetry. In this case the 8-brane Chern-Simons term becomes important. In the confined phase it generates a gradient of the pseudoscalar “pion,” which carries a nonvanishing baryon charge. Above a critical value of the chemical potential there is a second-order phase transition to a mixed phase which includes also ordinary baryonic matter. However, at fixed baryon charge density the matter is purely pion-gradient above a critical magnetic field. In the deconfined chiral-symmetric phase at nonzero chemical potential the magnetic field induces an axial current. We also compute the magnetization of the baryonic matter and find that it is paramagnetic in all three phases but with nonlinear behavior at a large magnetic field.

We investigate the physics of a charged scalar particle moving in conformally flat spacetime with the conformal factor depending only on time in the framework of quantum electrodynamics (QED). In particular, we show that the radiation-reaction force derived from QED agrees with the classical counterpart in the limit $\hslash \to 0$ using the fact that to lowest order in $\hslash$ the charged scalar field theory with mass $m$ in conformally flat spacetime with conformal factor $\Omega (t)$, which we call Model B, is equivalent to that in flat spacetime with a time-dependent mass $m\Omega (t)$, which we call Model A, at tree level in this limit. We also consider the one-loop QED corrections to these two models in the semiclassical approximation. We find nonzero one-loop corrections to the mass and Maxwell’s equations in Model A at order ${\hslash }^{-1}$. This does not mean, however, that the corresponding one-loop corrections in Model B are nonzero because the equivalence of these models through a conformal transformation breaks down at one loop. We find that the one-loop corrections vanish in the limit $\hslash \to 0$ in Model B.

In this last paper in a series of three on weakly interacting massive particle (WIMP) dark matter in the Solar System, we focus on WIMPs bound to the system by gravitationally scattering off of planets. We present simulations of WIMP orbits in a toy solar system consisting of only the Sun and Jupiter. As previous work suggested, we find that the density of gravitationally captured WIMPs at the Earth is small and largely insensitive to the details of elastic scattering in the Sun. However, we find that the density of gravitationally captured WIMPs may be affected by external Galactic gravitational fields. If such fields are unimportant, the density of gravitationally captured WIMPs at the Earth should be similar to the maximum density of WIMPs captured in the Solar System by elastic scattering in the Sun. Using standard assumptions about the halo WIMP distribution function, we find that the gravitationally captured WIMPs contribute negligibly to direct detection event rates. While these WIMPs do dominate the annihilation rate of WIMPs in the Earth, the resulting event rate in neutrino telescopes is too low to be observed in next-generation neutrino telescopes.

We calculate the annihilation rate of weakly interacting massive particles (WIMPs) in the Sun as a function of their mass and elastic scattering cross section. One byproduct of the annihilation, muon neutrinos, may be observed by the next generation of neutrino telescopes. Previous estimates of the annihilation rate assumed that any WIMPs from the Galactic dark halo that are captured in the Sun by elastic scattering off solar nuclei quickly reach thermal equilibrium in the Sun. Using simulations of WIMP orbits in the Solar System in the case that spin-independent scattering dominates in the Sun (and extrapolating to the case when spin-dependent scattering dominates), we show that the optical depth of the Sun to WIMPs and the gravitational forces from planets both serve to decrease the annihilation rate below these estimates. While we find that the sensitivity of upcoming ${\mathrm{km}}^3$-scale neutrino telescopes to $\sim 100\mathrm{GeV}$ WIMPs is virtually unchanged from previous estimates, the sensitivity of these experiments to $\sim 10\mathrm{TeV}$ WIMPs may be an order of magnitude less than the standard calculations would suggest. The new estimates of the annihilation rates should guide future experiment design and improve the mapping from neutrino event rates to WIMP parameter space.

The next generation of dark matter (DM) direct detection experiments and neutrino telescopes will probe large swaths of dark matter parameter space. In order to interpret the signals in these experiments, it is necessary to have good models of both the halo DM streaming through the Solar System and the population of DM bound to the Solar System. In this paper, the first in a series of three on DM in the Solar System, we present simulations of orbits of DM bound to the Solar System by solar capture in a toy solar system consisting of only the Sun and Jupiter, assuming that DM consists of a single species of weakly interacting massive particle (WIMP). We describe how the size of the bound WIMP population depends on the WIMP mass $m_{\chi }$, spin-independent cross section ${\sigma }_p^{\mathrm{SI}}$, and spin-dependent cross section ${\sigma }_p^{\mathrm{SD}}$. Using a standard description of the Galactic DM halo, we find that the maximum enhancement to the direct detection event rate, consistent with current experimental constraints on the WIMP-nucleon cross section, is $<1\%$ relative to the event rate from halo WIMPs, while the event rate from neutrinos from WIMP annihilation in the center of the Earth is unlikely to meet the threshold of next-generation, ${\mathrm{km}}^3$-sized (IceCube, KM3NeT) neutrino telescopes.

In the standard slow-roll inflationary cosmology, quantum fluctuations in a single field, the inflaton, generate approximately Gaussian primordial density perturbations. At present, the bispectrum and trispectrum of the density perturbations have not been observed and the probability distribution for these perturbations is consistent with Gaussianity. However, Planck satellite data will bring a new level of precision to bear on this issue, and it is possible that evidence for non-Gaussian effects in the primordial distribution will be discovered. One possibility is that a trispectrum will be observed without evidence for a nonzero bispectrum. It is not difficult for this to occur in inflationary models where quantum fluctuations in a field other than the inflaton contribute to the density perturbations. A natural question to ask is whether such an observation would rule out the standard scenarios. We explore this issue and find that it is possible to construct single-field models in which inflaton-generated primordial density perturbations have an observable trispectrum, but a bispectrum that is too small to be observed by the Planck satellite. However, an awkward fine-tuning seems to be unavoidable.

We study the possibility that Kaluza-Klein dark matter in a model with one universal extra dimension is responsible for the recent observations of the PAMELA and ATIC experiments. In this model, the dark matter particles annihilate largely to charged leptons, which enables them to produce a spectrum of cosmic ray electrons and positrons consistent with the PAMELA and ATIC measurements. To normalize to the observed signal, however, large boost factors ($\sim {10}^3$) are required. Despite these large boost factors and significant annihilation to hadronic modes (35%), we find that the constraints from cosmic ray antiproton measurements can be satisfied. Relic abundance considerations in this model force us to consider a rather specific range of masses (approximately 600–900 GeV) which is very similar to the range required to generate the ATIC spectral feature. The results presented here can also be used as a benchmark for model-independent constraints on dark matter annihilation to hadronic modes.

We estimate the production rate of axion-type particles in the core of the Earth, at a temperature $T\approx 5000\mathrm{K}$. We constrain thermal geo-axion emission by demanding a core-cooling rate less than $\mathcal{O}(100)\mathrm{K}/\mathrm{Gyr}$, as suggested by geophysics. This yields a “nonstellar” (unaffected by extreme stellar temperatures or densities) bound on the axion-electron (ae) fine structure constant, ${\alpha }_{ae}\lesssim {10}^{-18}$, stronger than the existing accelerator (vacuum) bound by 4 orders of magnitude. We consider the prospects for measuring the geo-axion flux through conversion into photons in a geoscope; such measurements can further constrain ${\alpha }_{ae}$.

We compute the two-loop renormalization functions, in the $R{I}^{\prime }$ scheme, of local bilinear quark operators $\overline{\psi }\Gamma \psi$, where $\Gamma$ corresponds to the vector, axial-vector, and tensor Dirac operators, in the lattice formulation of QCD. We consider both the flavor nonsinglet and singlet operators. We use the clover action for fermions and the Wilson action for gluons. Our results are given as a polynomial in $c_{\mathrm{SW}}$, in terms of both the renormalized and bare coupling constant, in the renormalized Feynman gauge. Finally, we present our results in the $\overline{MS}$ scheme, for easier comparison with calculations in the continuum. The corresponding results, for fermions in an arbitrary representation, together with some special features of superficially divergent integrals, are included in the appendices.

In this paper we study the breaking of chiral symmetry with nonconfining powerlike potentials. The region of allowed exponents is identified and, after the previous study of confining (positive exponent) potentials, we now specialize in shorter range nonconfining potentials, with a negative exponent. These nonconfining potentials are close to the Coulomb potential, and they are also relevant as corrections to the linear confinement, and as models for the quark potential at the deconfinement transition. The mass-gap equation is constructed and solved, and the quark mass, the chiral angle, and the quark energy are calculated analytically with an exponent expansion in the neighborhood of the Coulomb potential. It is demonstrated that chiral symmetry breaking occurs, but only the chiral invariant false vacuum and a second nontrivial vacuum exist. Moreover chiral symmetry breaking is led by the ultraviolet part of the potential, with no infrared enhancement of the quark mass. Thus the breaking of chiral symmetry driven by nonconfining potentials differs from the one lead by confining potentials.

In the minimal supersymmetric standard model the $R$-parity violating interactions can trigger various exotic three-body decays for the top quark, which may be accessible at the LHC. In this work we examine the $R$-violating decays $t\to c{X}_1{X}_2$, which include the tree-level processes $t\to c{\ell }_i^{-}{\ell }_j^{+}$ (${\ell }_i=e$, $\mu$, $\tau$) and $t\to c{d}_i{\overline{d}}_j$ ($d_i=d$, $s$, $b$), as well as the loop-induced processes $t\to cgX$ ($X=g$, $\gamma$, $Z$, $h$). We find that the hereto weakly constrained $R$-violating couplings can render the decay branching ratios quite sizable, some of which already reach the sensitivity of the Tevatron collider and can be explored at the LHC with better sensitivity.

We present a detailed investigation of the spacelike pion’s electromagnetic form factor using three-point QCD sum rules that exclusively involve nonlocal condensates. Our main methodological tools are a spectral density which includes $O({\alpha }_s)$ corrections, a suitably improved Gaussian ansatz to model the distribution of the average momentum of quarks in the QCD vacuum, and a perturbative scheme that avoids Landau singularities. Using this framework, we obtain predictions for the pion form factor together with error estimates originating from intrinsic theoretical uncertainties owing to the perturbative expansion and the nonperturbative method applied. We also discuss our results in comparison with other calculations, in particular, with those following from the AdS/QCD correspondence. We find good agreement of our predictions with measurements in the range of momenta covered by the existing experimental data between 1 and $10{\mathrm{GeV}}^2$.

We have performed a search for the rare leptonic decays $B^{+}\to {\ell }^{+}{\nu }_{\ell }$($l=e,\mu$), using data collected at the ${\rm Y}(4S)$ resonance by the BABAR detector at the PEP-II storage ring. In a sample of $468\times {10}^6$ $B\overline{B}$ pairs we find no evidence for a signal and set an upper limit on the branching fractions $\mathcal{B}(B^{+}\to {\mu }^{+}{\nu }_{\mu })<1.0\times {10}^{-6}$ and $\mathcal{B}(B^{+}\to e^{+}{\nu }_e)<1.9\times {10}^{-6}$ at the 90% confidence level, using a Bayesian approach.

The Baumgarte-Shapiro-Shibata-Nakamura (BSSN) and standard gauge equations are written in covariant form with respect to spatial coordinate transformations. The BSSN variables are defined as tensors with no density weights. This allows us to evolve a given set of initial data using two different coordinate systems and to relate the results using the familiar tensor transformation rules. Two variants of the covariant equations are considered. These differ from one another in the way that the determinant of the conformal metric is evolved.

In Gauss-Bonnet braneworld cosmology, the Friedmann equation of our four-dimensional Universe on 3-brane is modified in a high energy regime (Gauss-Bonnet regime), while the standard expansion law is reproduced in low energies (standard regime). We investigate the Gauss-Bonnet braneworld cosmological effect on the thermal relic density of cold dark matter when the freeze-out of the dark matter occurs in the Gauss-Bonnet regime. We find that the resultant relic density is considerably reduced when the transition temperature, which connects the Gauss-Bonnet regime with the standard regime, is low enough. This result is in sharp contrast with the result previously obtained in the Randall-Sundrum braneworld cosmology, where the relic density is enhanced.

The accelerating expansion of our Universe at present could be driven by an unknown energy component (dark energy) or a modification of general relativity (modified gravity). In this paper we revisit the constraints on a phenomenological model which interpolates between the pure $\Lambda \mathrm{CDM}$ model and the Dvali-Gabadadze-Porrati braneworld model with an additional parameter $\alpha$. Combining the cosmic microwave background , baryon acoustic oscillations, and type Ia supernovae, as well as some high-redshift observations, such as the gamma-ray bursts and the measurements of linear growth factors, we obtain the tight constraint on the parameter $\alpha =0.254\pm 0.153$ (68% C.L.), which implies that the flat Dvali-Gabadadze-Porrati model is incompatible with the current observations, while the pure $\Lambda \mathrm{CDM}$ model still fits the data very well. Finally, we simulate the future measurements with higher precisions and find that the constraint on $\alpha$ can be improved by a factor of 2 when compared to the present constraints.

We present a new numerical scheme to treat the nonlinear evolution of cosmological power spectra. Governing equations for matter power spectra have been previously derived by a nonperturbative technique with closure approximation. Solutions of the resultant closure equations just correspond to the resummation of an infinite class of perturbation corrections, and they consistently reproduce the one-loop results of standard perturbation theory. We develop a numerical algorithm to solve closure evolutions in both perturbative and nonperturbative regimes. The present numerical scheme is particularly suited for examining nonlinear matter power spectrum in general cosmological models, including modified theory of gravity. As a demonstration, we study weakly nonlinear evolution of power spectrum in a class of modified gravity models, as well as various dark energy models.

We discuss a three-flavor lattice QCD action with clover improvement in which the fermion matrix has single level stout smearing for the hopping terms together with unsmeared links for the clover term. With the (tree-level) Symanzik improved gluon action this constitutes the stout link nonperturbative clover or SLiNC action. To cancel $O(a)$ terms the clover term coefficient has to be tuned. We present here results of a nonperturbative determination of this coefficient using the Schrödinger functional and as a by-product a determination of the critical hopping parameter. Comparisons of the results are made with lowest order perturbation theory.

Higgs mediated flavor violating electromagnetic interactions, induced at the one-loop level by a nondiagonal $H{f}_i{f}_j$ vertex, with $f_i$ and $f_j$ charged leptons or quarks, are studied within the context of a completely general effective Yukawa sector that comprises $S{U}_L(2)\times U_Y(1)$-invariant operators of up to dimension-six. Exact formulae for the one-loop $\gamma f_i{f}_j$ and $\gamma \gamma f_i{f}_j$ couplings are presented and their related processes used to study the phenomena of Higgs mediated lepton flavor violation. The experimental limit on the $\mu \to e\gamma$ decay is used to derive a bound on the branching ratio of the $\mu \to e\gamma \gamma$ transition, which is 6 orders of magnitude stronger than the current experimental limit. Previous results on the $\tau \to \mu \gamma$ and $\tau \to \mu \gamma \gamma$ decays are reproduced. The possibility of detecting signals of lepton flavor violation at $\gamma \gamma$ colliders is explored through the $\gamma \gamma \to l_i{l}_j$ reaction, putting special emphasis on the $\tau \mu$ final state. Using the bound imposed on the $H\tau \mu$ vertex by the current experimental data on the muon anomalous magnetic moment, it is found that about half a hundred events may be produced in the International Linear Collider.