A gravitational-wave traversing the line of sight to a distant source produces a frequency shift which contributes to redshift space distortion. As a consequence, gravitational waves are imprinted as density fluctuations in redshift space. The gravitational-wave contribution to the redshift space power spectrum has a different $\mu$ dependence as compared to the dominant contribution from peculiar velocities. This, in principle, allows the two signals to be separated. The prospect of a detection is most favorable at the highest observable redshift $z$. Observations of redshifted 21-cm radiation from neutral hydrogen hold the possibility of probing very high redshifts. We consider the possibility of detecting primordial gravitational waves using the redshift space neutral hydrogen power spectrum. However, we find that the gravitational-wave signal, though present, will not be detectable on superhorizon scales because of cosmic variance and on subhorizon scales where the signal is highly suppressed.

The concept of “dyadotorus” was recently introduced to identify in the Kerr-Newman geometry the region where vacuum polarization processes may occur, leading to the creation of $e^{-}-e^{+}$ pairs. This concept generalizes the original concept of “dyadosphere” initially introduced for Reissner-Nordström geometries. The topology of the axially symmetric dyadotorus is studied for selected values of the electric field and its electromagnetic energy is estimated by using three different methods all giving the same result. It is shown by a specific example the difference between a dyadotorus and a dyadosphere. The comparison is made for a Kerr-Newman black hole with the same total mass energy and the same charge to mass ratio of a Reissner-Nordström black hole. It turns out that the Kerr-Newman black hole leads to larger values of the electromagnetic field and energy when compared to the electric field and energy of the Reissner-Nordström one. The significance of these theoretical results for the realistic description of the process of gravitational collapse leading to black hole formation as well as the energy source of gamma ray bursts are also discussed.

The implementation of seesaw mechanisms to give mass to neutrinos in the presence of an anomaly-free $U(1{)}_X$ gauge symmetry is discussed in the context of minimal extensions of the standard model. It is shown that type-I and type-III seesaw mechanisms cannot be simultaneously implemented with an anomaly-free local $U(1{)}_X$, unless the symmetry is a replica of the well-known hypercharge. For combined type-I/II or type-III/II seesaw models it is always possible to find nontrivial anomaly-free charge assignments, which are however tightly constrained, if the new neutral gauge boson is kinematically accessible at LHC. The discovery of the latter and the measurement of its decays into third-generation quarks, as well as its mixing with the standard $Z$ boson, would allow one to discriminate among different seesaw realizations.

The cross section for inclusive charm production by a low-energy antiproton beam is calculated using the parton model and next-to-leading-order perturbative QCD. For an antiproton beam with a momentum of 15 GeV, the charm cross section at next-to-leading order in the QCD coupling constant changes by more than an order of magnitude as the charm quark mass is varied from 1.3 to 1.7 GeV. The variations can be reduced by demanding that the same value of the charm quark mass give the measured charm cross sections for fixed-target experiments with a proton beam. The resulting estimate for the charm cross section from a low-energy antiproton beam is large enough to allow the study of charm meson mixing.

We study the doubly charmful two-body and three-body baryonic $B$ decays $\overline{B}\to {\Lambda }_c^{+}{\overline{\Lambda }}_c^{-}$ and $\overline{B}\to {\Lambda }_c^{+}{\overline{\Lambda }}_c^{-}\overline{K}$. As pointed out before, a naive estimate of the branching ratio $\mathcal{O}({10}^{-8})$ for the latter decay is too small by 3 to 4 orders of magnitude compared to experiment. Previously, it has been shown that a large enhancement for the ${\Lambda }_c^{+}{\overline{\Lambda }}_c^{-}\overline{K}$ production can occur due to a charmoniumlike resonance (e.g. $X(4630)$ discovered by Belle) with a mass near the ${\Lambda }_c{\overline{\Lambda }}_c$ threshold. Motivated by the BABAR’s observation of a resonance in the ${\Lambda }_c\overline{K}$ system with a mass of order 2930 MeV, we study in this work the contribution to $\overline{B}\to {\Lambda }_c^{+}{\overline{\Lambda }}_c^{-}\overline{K}$ from the intermediate state ${\Xi }_c(2980)$ which is postulated to be a first positive-parity excited $D$-wave charmed baryon state. Assuming that a soft $q\overline{q}$ quark pair is produced through the $\sigma$ and $\pi$ meson exchanges in the configuration for $\overline{B}\to {\Xi }_c(2980){\overline{\Lambda }}_c$ and ${\Lambda }_c{\overline{\Lambda }}_c$, it is found that branching ratios of $\overline{B}\to {\Lambda }_c^{+}{\overline{\Lambda }}_c^{-}\overline{K}$ and $\overline{B}\to {\Lambda }_c^{+}{\overline{\Lambda }}_c^{-}$ are of order $3.5\times {10}^{-4}$ and $5\times {10}^{-5}$, respectively, in agreement with experiment except that the prediction for the ${\Lambda }_c{\overline{\Lambda }}_c{K}^{-}$ is slightly smaller. In conjunction with our previous analysis, we conclude that the enormously large rate of $\overline{B}\to {\Lambda }_c^{+}{\overline{\Lambda }}_c^{-}\overline{K}$ arises from the resonances ${\Xi }_c(2980)$ and $X(4630)$.

The coherent contribution of all neutrons in neutrino-nucleus scattering due to the neutral current is examined considering the Spallation Neutron Source as a source of neutrinos. Spallation Neutron Source is a prolific pulsed source of electron and muon neutrinos as well as muon antineutrinos.

In this note we investigate the generalized massive gravity in asymptotically ${\mathrm{AdS}}_3$ spacetime by combining the two mass terms of topological massive gravity and new massive gravity theory. We study the linearized excitations around the ${\mathrm{AdS}}_3$ background and find that at a specific value of a certain combination of the two mass parameters (chiral line), one of the massive graviton solutions becomes the left-moving massless mode. It is shown that the theory is chiral at this line under Brown-Henneaux boundary condition. Because of this degeneration of the gravitons the new log solution which has a logarithmic asymptotic behavior is also a solution to this gravity theory at the chiral line. The log boundary condition which was proposed to accommodate this log solution is proved to be consistent at this chiral line. The resulting theory is no longer chiral except at a special point on the chiral line, where another new solution with log-square asymptotic behavior exists. At this special point, we prove that a new kind of boundary condition called log-square boundary condition, which accommodates this new solution, can be consistent.

We study the leading thermal corrections to various observables in the high-energy limit in supersymmetric theories and observe that they preserve supersymmetry. Our findings generalize previous observations on the equality of asymptotic thermal masses in weakly coupled plasmas. We observe supersymmetry in the leading thermal effects for both the real and imaginary parts of self-energies, on the light cone and away from it, in both weakly and strongly interacting theories. All observed supersymmetry violations are found to be suppressed by more than two powers of the (large) energy.

We study how the supersymmetry algebra copes with gravitational duality. As a playground, we consider a charged Taub–Newman-Unti-Tamburino(NUT) solution of $D=4$, $\mathcal{N}=2$ supergravity. We find explicitly its Killing spinors, and the projection they obey provides evidence that the dual magnetic momenta necessarily have to appear in the supersymmetry algebra. The existence of such a modification is further supported using an approach based on the Nester form. In the process, we find new expressions for the dual magnetic momenta, including the NUT charge. The same expressions are then rederived using gravitational duality.

A dynamical theory of traversable wormholes is detailed in spherical symmetry. Generically a wormhole consists of a tunnel of trapped surfaces between two mouths, defined as temporal outer trapping horizons with opposite senses, in mutual causal contact. In static cases, the mouths coincide as the throat of a Morris-Thorne wormhole, with surface gravity providing an invariant measure of the radial curvature or “flaring-out”. The null energy condition must be violated at a wormhole mouth. Zeroth, first, and second laws are derived for the mouths, as for black holes. Dynamic processes involving wormholes are reviewed, including enlargement or reduction, and interconversion with black holes. A new area of wormhole thermodynamics is suggested.

We study the bulk viscosity of neutron star matter including $\Lambda$ hyperons in the presence of quantizing magnetic fields. Relaxation time and bulk viscosity due to both the nonleptonic weak process involving $\Lambda$ hyperons and direct Urca processes are calculated here. In the presence of a strong magnetic field of ${10}^{17}\mathrm{G}$, the hyperon bulk viscosity coefficient is reduced, whereas bulk viscosity coefficients due to direct Urca processes are enhanced compared with their field free cases when many Landau levels are populated by protons, electrons, and muons.

We determine viscosity corrections to the retarded, advanced and symmetric gluon self-energies and to the static propagator in the weak-coupling “hard loop” approximation to high-temperature QCD. We apply these results to calculate the imaginary part of the heavy-quark potential which is found to be smaller (in magnitude) than at vanishing viscosity. This implies a smaller decay width of quarkonium bound states in an anisotropic plasma.

The dynamics of heavy quarkonium systems in the strong coupling regime reduces to a quantum mechanical problem with a number of potentials which may be organized in powers of $1/m$, $m$ being the heavy quark mass. The potentials must be calculated nonperturbatively, for instance, in lattice QCD. It is well known that the long-distance behavior of the static ($1/m^0$) potential is well reproduced by an effective string theory. We show that this effective string theory, if correct, should also reproduce the long-distance behavior of all $1/m$ suppressed potentials. We demonstrate the practical usefulness of this result by finding a suitable parameterization of the recently calculated $1/m$ potential. We also calculate the $1/m^2$ velocity-dependent and spin-dependent potentials. Once Poincaré invariance is implemented, the shapes of most of the spin-independent potentials are fully predicted in terms of the string tension and the shapes of the spin-dependent ones in terms of a single parameter.

WIMP-less dark matter [J. L. Feng and J. Kumar, Phys. Rev. Lett. 101, 231301 (2008).] offers an attractive framework in which dark matter can be very light. We investigate the implications of such scenarios on invisible decays of bottomonium states for dark matter with a mass less than around 5 GeV. We relate these decays to measurements of nucleon-dark matter elastic scattering. We also investigate the effect that a coupling to $s$ quarks has on flavor changing $b\to s$ processes involving missing energy.

We present a search for new particles which produce narrow two-jet (dijet) resonances using proton-antiproton collision data corresponding to an integrated luminosity of $1.13{\mathrm{fb}}^{-1}$ collected with the CDF II detector. The measured dijet mass spectrum is found to be consistent with next-to-leading-order perturbative QCD predictions, and no significant evidence of new particles is found. We set upper limits at the 95% confidence level on cross sections times the branching fraction for the production of new particles decaying into dijets with both jets having a rapidity magnitude $|y|<1$. These limits are used to determine the mass exclusions for the excited quark, axigluon, flavor-universal coloron, $E_6$ diquark, color-octet techni-$\rho$, $W^{\prime }$, and $Z^{\prime }$.

We report the results of a search for $Z(4430{)}^{-}$ decay to $J/\psi {\pi }^{-}$ or $\psi (2S){\pi }^{-}$ in $B^{-,0}\to J/\psi {\pi }^{-}{K}^{0,+}$ and $B^{-,0}\to \psi (2S){\pi }^{-}{K}^{0,+}$ decays. The data were collected with the BABAR detector at the SLAC PEP-II asymmetric-energy $e^{+}{e}^{-}$ collider operating at center-of-mass energy 10.58 GeV, and the sample corresponds to an integrated luminosity of $413{\mathrm{fb}}^{-1}$. Each $K{\pi }^{-}$ mass distribution exhibits clear $K^{*}(892)$ and $K_2^{*}(1430)$ signals, and the efficiency-corrected spectrum is well described by a superposition of the associated Breit-Wigner intensity distributions, together with an $S$-wave contribution obtained from the LASS $I=1/2$ $K{\pi }^{-}$ scattering amplitude measurements. Each $K{\pi }^{-}$ angular distribution varies significantly in structure with $K{\pi }^{-}$ mass, and is represented in terms of low-order Legendre polynomial moments. We find that each $J/\psi {\pi }^{-}$ or $\psi (2S){\pi }^{-}$ mass distribution is well described by the reflection of the measured $K{\pi }^{-}$ mass and angular distribution structures. We see no significant evidence for a $Z(4430{)}^{-}$ signal for any of the processes investigated, neither in the total $J/\psi {\pi }^{-}$ or $\psi (2S){\pi }^{-}$ mass distribution, nor in the corresponding distributions for the regions of $K{\pi }^{-}$ mass for which observation of the $Z(4430{)}^{-}$ signal was reported. We obtain branching-fraction upper limits $\mathcal{B}(B^{-}\to Z^{-}{\overline{K}}^0,Z^{-}\to J/\psi {\pi }^{-})<1.5\times {10}^{-5}$, $\mathcal{B}(B^0\to Z^{-}{K}^{+},Z^{-}\to J/\psi {\pi }^{-})<0.4\times {10}^{-5}$, $\mathcal{B}(B^{-}\to Z^{-}{\overline{K}}^0,Z^{-}\to \psi (2S){\pi }^{-})<4.7\times {10}^{-5}$, and $\mathcal{B}(B^0\to Z^{-}{K}^{+},Z^{-}\to \psi (2S){\pi }^{-})<3.1\times {10}^{-5}$ at 95% confidence level, where the $Z(4430{)}^{-}$ mass and width have been fixed to the reported central values.

The low reheat temperature at the end of inflation from the gravitino bound constrains the creation of heavy Majorana neutrinos associated with models of leptogenesis. However, a detailed view of the reheating of the Universe at the end of inflation implies that the maximum temperature during reheating, $T_{\max }$, can be orders of magnitude higher than the final reheat temperature. This then allows for the production of the heavy Majorana neutrinos needed for leptogenesis. We carry out the complementary calculation of the gravitino production during reheating and its dependence on $T_{\max }$. We find that the gravitino abundance generated during reheating for a quartic potential is comparable to the standard estimate of the abundance generated after reheating and study its consequences for leptogenesis.

The AMANDA-II detector, operating since 2000 in the deep ice at the geographic South Pole, has accumulated a large sample of atmospheric muon neutrinos in the 100 GeV to 10 TeV energy range. The zenith angle and energy distribution of these events can be used to search for various phenomenological signatures of quantum gravity in the neutrino sector, such as violation of Lorentz invariance or quantum decoherence. Analyzing a set of 5511 candidate neutrino events collected during 1387 days of livetime from 2000 to 2006, we find no evidence for such effects and set upper limits on violation of Lorentz invariance and quantum decoherence parameters using a maximum likelihood method. Given the absence of evidence for new flavor-changing physics, we use the same methodology to determine the conventional atmospheric muon neutrino flux above 100 GeV.

We discuss the implications of assuming a four-zero Yukawa texture for the properties of the charged Higgs boson within the context of the general two-Higgs-doublet model of type III. We begin by presenting a detailed analysis of the charged Higgs boson couplings with heavy quarks and the resulting pattern for its decays. The production of charged Higgs bosons is also sensitive to the modifications of its couplings, so that we also evaluate the resulting effects on the top decay $t\to b{H}^{+}$ as well as on “direct” $c\overline{b}\to H^{+}+\mathrm{c}.\mathrm{c}.$ and “indirect” $q\overline{q},gg\to \overline{t}b{H}^{+}+\mathrm{c}.\mathrm{c}.$ production. A significant scope exists at the Large Hadron Collider for several $H^{\pm }$ production and decay channels combined to enable one to distinguish between such a model and alternative two-Higgs-doublet scenarios.