Motivated by the polarization anomaly in the $B\to \varphi (1020)K^{*}(892)$ decay, we extend our search for other $K^{*}$ final states in the decay $B^0\to \varphi (1020)K^{*0}$ with the $K^{*0}\to K^{+}{\pi }^{-}$ invariant mass above 1.6 GeV. The final states considered include the $K^{*}(1680{)}^0$, $K_3^{*}(1780{)}^0$, $K_4^{*}(2045{)}^0$, and a $K\pi$ spin-zero nonresonant component. We also search for $B^0\to \varphi {\overline{D}}^0$ decay with the same final state. The analysis is based on a sample of about $384\times {10}^6$ $B\overline{B}$ pairs recorded with the BABAR detector. We place upper limits on the branching fractions $\mathcal{B}(B^0\to \varphi K^{*}(1680{)}^0)<3.5\times {10}^{-6}$, $\mathcal{B}(B^0\to \varphi K_3^{*}(1780{)}^0)<2.7\times {10}^{-6}$, $\mathcal{B}(B^0\to \varphi K_4^{*}(2045{)}^0)<15.3\times {10}^{-6}$, and $\mathcal{B}(B^0\to \varphi {\overline{D}}^0)<11.7\times {10}^{-6}$ at 90% C.L. The nonresonant contribution is consistent with the measurements in the lower invariant mass range.

We report the first observation of the decay ${\overline{B}}^0\to D_s^{+}\Lambda \overline{p}$ with a statistical significance of $6.6\sigma$. We measure $\mathcal{B}({\overline{B}}^0\to D_s^{+}\Lambda \overline{p})=(2.9\pm 0.7\pm 0.5\pm 0.4)\times {10}^{-5}$, where the first error is statistical, the second is systematic, and the third error comes from the uncertainty in $\mathcal{B}(D_s^{+}\to \varphi {\pi }^{+})$. The data used for this analysis was accumulated at the ${\rm Y}(4S)$ resonance, using the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. The integrated luminosity of the data sample is $414{\mathrm{fb}}^{-1}$, corresponding to $449\times {10}^6$ $B\overline{B}$ pairs.

The amplitude of zero angle scattering of an electron on photon in the 3rd QED order of fine structure constant with ${\gamma }^{*}\gamma$ intermediate state converting into quark-antiquark is considered. Utilizing analytic properties of the elastic photon-photon scattering amplitude, an explicit expression for the differential cross section of quark-antiquark pair production at the electron-photon collision in peripheral kinematics is apparently derived. The limiting case of small transferred momenta with an application of the Weizsäcker-Williams like relation gives the sum rule for the photon target, bringing into the relation the sum of ratios of the four powers of the quark charges to squared quark masses with an integral over the total $\gamma \gamma \to 2\mathrm{jets}$ cross section.

Intriguing evidence has been accumulating for the production of cosmic rays in the Cygnus region of the galactic plane. We here show that the IceCube experiment can produce incontrovertible evidence for cosmic ray acceleration by observing the neutrinos from the decay of charged pions accompanying the TeV photon flux observed in the HEGRA, Whipple, Tibet, and Milagro experiments. Our assumption is that the TeV photons observed are the decay products of neutral pions produced by cosmic ray accelerators in the nearby spiral arm of the galaxy. Because of the proximity of the sources, IceCube will obtain evidence at the $5\sigma$ level in 15 years of observation.

Using a confining potential, we consider spherically symmetric vacuum (static black hole) solutions in a brane-world scenario. Working with a constant curvature bulk, two interesting cases/solutions are studied. A Schwarzschild–de Sitter black hole solution similar to the standard solution in the presence of a cosmological constant is obtained which confirms the idea that an extra term in the field equations on the brane can play the role of a positive cosmological constant and may be used to account for the accelerated expansion of the universe. The other solution is one in which we can have a proper potential to explain the galaxy rotation curves without assuming the existence of dark matter and without working with new modified theories (modified Newtonian dynamics).

We formulate a supersymmetric theory in which both a dilaton and a second-rank tensor play roles of compensators. The basic off-shell multiplets are a linear multiplet $(B_{\mu \nu },\chi ,\phi )$ and a vector multiplet $(A_{\mu },\lambda ;C_{\mu \nu \rho })$, where $\phi$ and $B_{\mu \nu }$ are, respectively, a dilaton and a second-rank tensor. The third-rank tensor $C_{\mu \nu \rho }$ in the vector multiplet is “dual” to the conventional $D$ field with 0 on-shell or 1 off-shell degree of freedom. The dilaton $\phi$ is absorbed into one longitudinal component of $A_{\mu }$, making it massive. Initially, $B_{\mu \nu }$ has 1 on-shell or 3 off-shell degrees of freedom, but it is absorbed into the longitudinal components of $C_{\mu \nu \rho }$. Eventually, $C_{\mu \nu \rho }$ with 0 on-shell or 1 off-shell degree of freedom acquires in total 1 on-shell or 4 off-shell degrees of freedom, turning into a propagating massive field. These basic multiplets are also coupled to chiral multiplets and a supersymmetric Dirac-Born-Infeld action. Some of these results are also reformulated in superspace. The proposed mechanism may well provide a solution to the long-standing puzzle of massless dilatons and second-rank tensors in supersymmetric models inspired by string theory.

We construct a calculable model of electroweak symmetry breaking in which the Higgs doublet emerges from the metastable SUSY breaking sector as a pseudo Nambu-Goldstone boson. The Higgs boson mass is further protected by the little Higgs mechanism, and naturally suppressed by a two-loop factor from the SUSY breaking scale of 10 TeV. Gaugino and sfermion masses arise from standard gauge mediation, but the Higgsino obtains a tree-level mass at the SUSY breaking scale. At 1 TeV, aside from new gauge bosons and fermions similar to other little Higgs models and their superpartners, our model predicts additional electroweak triplets and doublets from the SUSY breaking sector.

We introduce a simple quantum mechanical model in which time and space are discrete and periodic. These features avoid the complications related to continuous-spectrum operators and infinite-norm states. The model provides a tool for discussing the probabilistic interpretation of generally covariant quantum systems, without the confusion generated by spurious infinities. We use the model to illustrate the formalism of general-relativistic quantum mechanics, and to test the definition of multiple-event probability introduced in a companion paper [Phys. Rev. D 75, 084033 (2007)]. We consider a version of the model with unitary time evolution and a version without unitary time evolution.

We study a class of metric-variation $f(R)$ models that accelerates the expansion without a cosmological constant and satisfies both cosmological and solar-system tests in the small-field limit of the parameter space. Solar-system tests alone place only weak bounds on these models, since the additional scalar degree of freedom is locked to the high-curvature general-relativistic prediction across more than 25 orders of magnitude in density, out through the solar corona. This agreement requires that the galactic halo be of sufficient extent to maintain the galaxy at high curvature in the presence of the low-curvature cosmological background. If the galactic halo and local environment in $f(R)$ models do not have substantially deeper potentials than expected in $\Lambda \mathrm{CDM}$, then cosmological field amplitudes $|f_R|\gtrsim {10}^{-6}$ will cause the galactic interior to evolve to low curvature during the acceleration epoch. Viability of large-deviation models therefore rests on the structure and evolution of the galactic halo, requiring cosmological simulations of $f(R)$ models, and not directly on solar-system tests. Even small deviations that conservatively satisfy both galactic and solar-system constraints can still be tested by future, percent-level measurements of the linear power spectrum, while they remain undetectable to cosmological-distance measures. Although we illustrate these effects in a specific class of models, the requirements on $f(R)$ are phrased in a nearly model-independent manner.

We discuss an effective field theory background containing the gravitational field, the dilaton, and a closed string tachyon, and couple this background to a gas of fundamental strings and D strings. Allowing for the possibility of a nonvanishing dilaton potential of Casimir type, we demonstrate the possibility of obtaining a nonsingular, static tachyon condensate phase with fixed dilaton. The time reversal of our solution provides a candidate effective field theory description of a Hagedorn phase of string gas cosmology with fixed dilaton.

In concordance cosmology, dark matter density perturbations generated by inflation lead to nonlinear, virialized minihalos, into which baryons collapse at redshift $z\sim 20$. We survey here novel baryon evolution produced by a modification of the power spectrum from white noise density perturbations at scales below $k\sim 10h{\mathrm{Mpc}}^{-1}$ (the smallest scales currently measured with the Lyman-$\alpha$ forest). Exotic dark matter dynamics, such as would arise from scalar dark matter with a late phase transition (similar to an axion, but with lower mass), or primordial black hole dark matter, create such an amplification of small scale power. The dark matter produced in such a phase transition collapses into minihalos, with a size given by the dark matter mass within the horizon at the phase transition. If the mass of the initial minihalos is larger than $\sim {10}^{-3}{M}_{\odot }$, the modified power spectrum is found to cause widespread baryon collapse earlier than standard $\Lambda \mathrm{CDM}$, leading to earlier gas heating. It also results in higher spin temperature of the baryons in the 21 cm line relative to $\Lambda \mathrm{CDM}$ at redshifts $z>20$ if the mass of the minihalo is larger than $1M_{\odot }$. It is estimated that experiments probing 21 cm radiation at high redshift will contribute a significant constraint on dark matter models of this type for initial minihalos larger than $\sim 10M_{\odot }$. These experiments may also detect (or rule out) primordial black holes as the dark matter in the window $30M_{\odot }\lesssim M_H\lesssim 4\times {10}^3{M}_{\odot }$ still left open by strong microlensing experiments and other astrophysical constraints. Early experiments reaching to $z\approx 15$ will constrain minihalos down to $\sim {10}^3{M}_{\odot }$.

Perturbations in the ionization fraction after recombination affect the Compton cooling of density perturbations. Once the gas temperature starts to decouple from the cosmic microwave background (CMB) temperature, ionization fraction perturbations can have a significant influence on the subsequent gas temperature perturbation evolution. This directly affects the 21 cm spin temperature of the gas, and also modifies the small-scale baryon perturbation evolution via the difference in baryon pressure. The effect on the gas temperature perturbations can be significant on all scales, and galactic-scale baryon perturbations are modified at the percent level at redshifts $z\gtrsim 100$ where numerical simulations are typically started.

We present results from several simulations of equal mass black holes with spin. The spin magnitudes are $S/m^2=0.8$ in all cases, but we vary the spin orientations arbitrarily, inside and outside the orbital plane. We find that in all but one case the final merged black hole acquires a kick of more than $1000\mathrm{km}/\mathrm{s}$, indicating that kicks of this magnitude are likely to be generic and should be expected for mergers with general spin orientations. The maximum kick velocity we find is $2500\mathrm{km}/\mathrm{s}$ and occurs for initial spins which are antialigned in the initial orbital plane.

We study a recently proposed formulation of overlap fermions at finite density. In particular, we compute the energy density as a function of the chemical potential and the temperature. It is shown that overlap fermions with chemical potential approach the correct continuum behavior.

Using effective Lagrangian arguments, I explore the qualitative behavior expected at finite temperature for two-flavor lattice QCD formulated with Wilson fermions and a twisted mass term. A rather rich phase structure is predicted, exhibiting Aoki’s parity violating phase along with a deconfinement region forming a conical structure in the space of coupling, hopping parameter, and twisted mass variables.

We analyze the possibility of probing nonstandard neutrino interactions (NSI, for short) through the detection of neutrinos produced in a future galactic supernova (SN). We consider the effect of NSI on the neutrino propagation through the SN envelope within a three-neutrino framework, paying special attention to the inclusion of NSI-induced resonant conversions, which may take place in the most deleptonized inner layers. We study the possibility of detecting NSI effects in a Megaton water Cherenkov detector, either through modulation effects in the ${\overline{\nu }}_e$ spectrum due to (i) the passage of shock waves through the SN envelope, (ii) the time dependence of the electron fraction, and (iii) the Earth matter effects; or, finally, through the possible detectability of the neutronization ${\nu }_e$ burst. We find that the ${\overline{\nu }}_e$ spectrum can exhibit dramatic features due to the internal NSI-induced resonant conversion. This occurs for nonuniversal NSI strengths of a few %, and for very small flavor-changing NSI above a $\mathrm{\text{few}}\times {10}^{-5}$.

A class of strongly interacting $2+1$ dimensional conformal field theories in a transverse magnetic field can be studied using the AdS/CFT duality. We compute zero momentum hydrodynamic response functions of maximally supersymmetric $2+1$ dimensional $SU(N)$ Yang-Mills theory at the conformal fixed point, in the large $N$ limit. With background magnetic field $B$ and electric charge density $\rho$, the Hall conductivity is found to be $\rho /B$. The result, anticipated on kinematic grounds in field theory, is obtained from perturbations of a four-dimensional AdS black hole with both electric and magnetic charges.

We derive the rate for transitions between de Sitter vacua by treating the field theory on the static patch as a thermal system. This reproduces the Coleman-De Luccia formalism for calculating the rate, but leads to a modified interpretation of the bounce solution and a different prediction for the evolution of the system after tunneling. The bounce is seen to correspond to a sequence of configurations interpolating between initial and final configurations on either side of the tunneling barrier, all of which are restricted to the static patch. The final configuration, which gives the initial data on the static patch for evolution after tunneling, is obtained from one-half of a slice through the center of the bounce, while the other half gives the configuration before tunneling. The formalism makes no statement about the fields beyond the horizon. This approach resolves several puzzling aspects and interpretational issues concerning the Coleman-De Luccia and Hawking-Moss bounces. We work in the limit where the backreaction of matter on metric can be ignored, but argue that the qualitative aspects remain in the more general case. The extension to tunneling between anti-de Sitter vacua is discussed.

The existence of dark matter (DM) at scales of a few parsecs down to $\simeq {10}^{-5}\mathrm{pc}$ around the centers of galaxies and, in particular, in the Galactic Center region has been considered in the literature. Under the assumption that such a DM clump, principally constituted by nonbaryonic matter (like weakly interacting massive particles) does exist at the center of our galaxy, the study of the $\gamma$-ray emission from the Galactic Center region allows us to constrain both the mass and the size of this DM sphere. Further constraints on the DM distribution parameters may be derived by observations of bright infrared stars around the Galactic Center. Hall and Gondolo [J. Hall and P. Gondolo, Phys. Rev. D 74, 063511 (2006)] used estimates of the enclosed mass obtained in various ways and tabulated by Ghez et al. [A. M. Ghez et al., Astron. Nachr. 324, 527 (2003); A. M. Ghez et al., Astrophys. J. 620, 744 (2005)]. Moreover, if a DM cusp does exist around the Galactic Center it could modify the trajectories of stars moving around it in a sensible way depending on the DM mass distribution. Here, we discuss the constraints that can be obtained with the orbit analysis of stars (as S2 and S16) moving inside the DM concentration with the present and next generations of large telescopes. In particular, consideration of the S2 star apoastron shift may allow improving limits on the DM mass and size.