The properties of the electric field of a two-body system consisting of a Reissner-Nordström black hole and a charged massive particle at rest have recently been analyzed in the framework of first order perturbation theory following the standard approach of Regge, Wheeler, and Zerilli. In the present paper we complete this analysis by numerically constructing and discussing the lines of force of the “effective” electric field of the sole particle with the subtraction of the dominant contribution of the black hole. We also give the total field due to the black hole and the particle. As the black hole becomes extreme an effect analogous to the Meissner effect arises for the electric field, with the “effective field” lines of the point charge being expelled by the outer horizon of the black hole. This effect existing at the level of test field approximation, i.e. by neglecting the backreaction on the background metric and electromagnetic field due to the particle’s mass and charge, is here found also at the complete perturbative level. We point out analogies with similar considerations for magnetic fields by Bičák and Dvořák. We also explicitly show that the linearization of the recently obtained Belinski-Alekseev exact solution coincides with our solution in the Regge-Wheeler gauge. Our solution thus represents a bridge between the test field solution, which neglects all the feedback terms, and the exact two-body solution, which takes into account all the nonlinearity of the interaction.

We study the boundary value problem for asymptotically flat stationary black ring solutions to the five-dimensional vacuum Einstein equations. Assuming the existence of two additional commuting axial Killing vector fields and the horizon topology of ${\mathrm{S}}^1\times {\mathrm{S}}^2$, we show that the only asymptotically flat black ring solution with a regular horizon is the Pomeransky-Sen’kov black ring solution.

We analyze the possibility that topological defects can act as a source of magnetic fields through the Harrison mechanism in the radiation era. We give a detailed relativistic derivation of the Harrison mechanism at first order in cosmological perturbations, and show that it is only efficient for temperatures above $T\simeq 0.2\mathrm{keV}$. Our main result is that the vector metric perturbations generated by the defects cannot induce vorticity in the matter fluids at linear order, thereby excluding the production of currents and magnetic fields. We show that anisotropic stress in the matter fluids is required to source vorticity and magnetic fields. Our analysis is relevant for any mechanism whereby vorticity is meant to be transferred purely by gravitational interactions, and thus would also apply to dark matter or neutrinos.

We present the results of a search for short-duration gravitational-wave bursts associated with 39 gamma-ray bursts (GRBs) detected by gamma-ray satellite experiments during LIGO’s S2, S3, and S4 science runs. The search involves calculating the crosscorrelation between two interferometer data streams surrounding the GRB trigger time. We search for associated gravitational radiation from single GRBs, and also apply statistical tests to search for a gravitational-wave signature associated with the whole sample. For the sample examined, we find no evidence for the association of gravitational radiation with GRBs, either on a single-GRB basis or on a statistical basis. Simulating gravitational-wave bursts with sine-Gaussian waveforms, we set upper limits on the root-sum-square of the gravitational-wave strain amplitude of such waveforms at the times of the GRB triggers. We also demonstrate how a sample of several GRBs can be used collectively to set constraints on population models. The small number of GRBs and the significant change in sensitivity of the detectors over the three runs, however, limits the usefulness of a population study for the S2, S3, and S4 runs. Finally, we discuss prospects for the search sensitivity for the ongoing S5 run, and beyond for the next generation of detectors.

We discuss non-Hermitian field theories where the spectrum of the Hamiltonian involves only real energies. We make three observations. (i) The theories obtained from supersymmetric theories by nonanticommutative deformations belong in many cases to this class. (ii) When the deformation parameter is small, the deformed theory enjoys the same supersymmetry algebra as the undeformed one. Half of the supersymmetries are manifest and the existence of another half can be deduced from the structure of the spectrum. (iii) Generically, the conventionally defined $S$-matrix is not unitary for such theories.

We show that, in the 3-3-1 model with right-handed neutrinos, small neutrino masses and large lepton flavor violating processes such as $\mu \to 3e$ and $\mu \to e\gamma$ can be obtained by just introducing an additional Higgs sextet. In the limit of vanishing of the Yukawa interaction among Higgs and lepton triplets $(h^{\nu }=0)$, the decay $\mu \to 3e$ strongly depends on the neutrino-mass patterns, but the $\mu \to e\gamma$ almost does not. The neutrino masses are not constrained by such processes in the cases of $h^{\nu }\ne 0$.

The AdS/CFT correspondence between string theory in AdS space and conformal field theories in physical space-time leads to an analytic, semiclassical model for strongly-coupled QCD which has scale invariance and dimensional counting at short distances and color confinement at large distances. The AdS/CFT correspondence also provides insights into the inherently nonperturbative aspects of QCD such as the orbital and radial spectra of hadrons and the form of hadronic wavefunctions. In particular, we show that there is an exact correspondence between the fifth-dimensional coordinate of anti–de Sitter (AdS) space $z$ and a specific light-front impact variable $\zeta$ which measures the separation of the quark and gluonic constituents within the hadron in ordinary space-time. This connection allows one to compute the analytic form of the frame-independent light-front wavefunctions of mesons and baryons, the fundamental entities which encode hadron properties and which allow the computation of decay constants, form factors and other exclusive scattering amplitudes. Relativistic light-front equations in ordinary space-time are found which reproduce the results obtained using the fifth-dimensional theory. As specific examples we compute the pion coupling constant $f_{\pi }$, the pion charge radius $⟨r_{\pi }^2⟩$ and examine the propagation of the electromagnetic current in AdS space, which determines the space and timelike behavior of the pion form factor and the pole of the $\rho$ meson.

The little Higgs mechanism, as realized in various models, requires a set of new massive gauge bosons, some of which mix with gauge bosons of the standard model. For a range of mixing angles the coupling of gauge bosons to scalars can become strong, ultimately resulting in a breakdown of perturbative calculation. This phenomenon is studied in the littlest Higgs model, where the approach to strong dynamics is characterized by increasing tree-level decay widths of the neutral $Z_H$ boson to lighter gauge bosons plus multiple scalars. These increasing widths suggest a distinctive qualitative collider signature for the approach to the strong coupling regime of large Higgs and other scalar multiplicities. In this work we catalog the kinematically allowed three-body decays of the $Z_H$, and calculate the partial width of the process $Z_H\to Z_{L}HH$. This partial width is found to be larger than the comparable two-body decay $Z_H\to Z_{L}H$ for values of the $SU(2)$ mixing angle cosine $\theta <0.13$, indicating divergence of the littlest Higgs sigma field expansion at values of cosine $\theta$ larger than a simple parametric calculation would suggest. Additionally, we present analytical expressions for all two-body decays of the littlest Higgs $Z_H$ gauge boson, including the effects of all final-state masses.

Leptoquark-Higgs interactions induce mixing between leptoquark (LQ) states with different chiralities once the electroweak symmetry is broken. In such LQ models Majorana neutrino masses are generated at 1-loop order. Here we calculate the neutrino mass matrix and explore the constraints on the parameter space enforced by the assumption that LQ-loops explain current neutrino oscillation data. LQs will be produced at the CERN LHC, if their masses are at or below the TeV scale. Since the fermionic decays of LQs are governed by the same Yukawa couplings, which are responsible for the nontrivial neutrino mass matrix, several decay branching ratios of LQ states can be predicted from measured neutrino data. Especially interesting is that large lepton flavor violating rates in muon and tau final states are expected. In addition, the model predicts that, if kinematically possible, heavier LQs decay into lighter ones plus either a standard model Higgs boson or a $Z^0/W^{\pm }$ gauge boson. Thus, experiments at the LHC might be able to exclude the LQ mechanism as an explanation of neutrino data.

The Higgs boson production by the gluon fusion and its decay into two photons at the LHC are investigated in the context of the gauge-Higgs unification scenario. The qualitative behaviors for these processes in the gauge-Higgs unification are quite distinguishable from those of the standard model and the universal extra dimension scenario because of the overall sign difference for the effective couplings induced by one-loop corrections through the Kaluza-Klein modes. For the Kaluza-Klein mode mass smaller than 1 TeV, the Higgs production cross section and its branching ratio into two photons are sizably deviated from those in the standard model. Associated with the discovery of the Higgs boson, this deviation may be measured at the LHC.

We study the threshold production of two pions induced by neutrinos in nucleon targets. The contribution of nucleon, pion, and contact terms are calculated using a chiral Lagrangian. The contribution of the Roper resonance, neglected in earlier studies, has also been taken into account. The numerical results for the cross sections are presented and compared with the available experimental data. It has been found that in the two-pion channels with ${\pi }^{+}{\pi }^{-}$ and ${\pi }^0{\pi }^0$ in the final state, the contribution of the $N^{*}(1440)$ is quite important and could be used to determine the $N^{*}(1440)$ electroweak transition form factors if experimental data with better statistics become available in the future.

I present analytical expressions for the collinear and soft-gluon corrections to Higgs production via the process $b\overline{b}\to H$ as well as $gg\to H$ through next-to-next-to-next-to-leading order (NNNLO). The soft corrections are complete, while the collinear corrections include leading and some subleading logarithms. Numerical results at the Tevatron and the CERN LHC are presented, primarily for $b\overline{b}\to H$. It is shown that the collinear terms greatly improve the soft and virtual approximation at next-to-leading order and next-to-next-to-leading order, especially when subleading terms are included. The NNNLO collinear and soft corrections provide significant enhancements to the total cross section. I also provide expressions for the collinear and soft corrections through NNNLO for the related Drell-Yan process.

We consider the effect of an expanding plasma on probe matter by determining time-dependent D7 embeddings in the holographic dual of an expanding viscous plasma. We calculate the chiral condensate and meson spectra including contributions of viscosity. The chiral condensate essentially confirms the expectation from the static black hole. For the meson spectra we propose a scheme that is in agreement with the adiabatic approximation. New contributions arise for the vector mesons at the order of the viscosity terms.

The continuation of the Liouville conformal field theory to $c\le 1$ is considered. The viability of an interpretation involving a timelike boson which is the conformal factor for two-dimensional asymptotically de Sitter geometries is examined. The conformal bootstrap leads to a three-point function with a unique analytic factor which is the same as that which appears along with the fusion coefficients in the minimal models. A corresponding nonanalytic factor produces a well-defined metric on fields only when the central charge is restricted to those of the topological minimal models, and when the conformal dimensions satisfy $h>(c-1)/24$. However, the theories considered here have a continuous spectrum which excludes the degenerate representations appearing in the minimal models. The $c=1$ theory has been investigated previously using similar techniques, and is identical to a nonrational conformal field theory (CFT) which arises as a limit of unitary minimal models. When coupled to unitary matter fields, the nonunitary theories with $c\le -2$ produce string amplitudes which are similar to those of the minimal string.

We investigate the influence of the asymmetric quark matter (${\rho }_u\ne {\rho }_d\ne {\rho }_s$) on the mass of the quasiparticles and the phase diagram of the chiral quark model parametrized at the one-loop level of the renormalized theory, using the optimized perturbation theory for the resummation of the perturbative series. The effect of various chemical potentials introduced in the grand canonical ensemble is investigated with the method of relativistic many-body theory. The temperature dependence of the topological susceptibility is estimated with the help of the Witten-Veneziano mass formula.

We study how black hole superradiance appears in string microscopic models of rotating black holes. In order to disentangle superradiance from finite-temperature effects, we consider an extremal, rotating D1-D5-P black hole that has an ergosphere and is not supersymmetric. We explain how the microscopic dual accounts for the superradiant ergosphere of this black hole. The bound $0<\omega <m{\Omega }_H$ on superradiant mode frequencies is argued to be a consequence of Fermi-Dirac statistics for the spin-carrying degrees of freedom in the dual conformal field theory. We also compute the superradiant emission rates from both sides of the correspondence, and show their agreement.

The future laser interferometric gravitational-wave detectors’ sensitivity can be improved using squeezed light. In particular, recently a scheme which uses the optical field with frequency-dependent squeeze factor, prepared by means of a relatively short ($\sim 30\mathrm{m}$) amplitude filter cavity, was proposed [Thomas Corbitt, Nergis Mavalvala, and Stan Whitcomb, Phys. Rev. D 70, 022002 (2004).]. Here we consider an improved version of this scheme, which allows one to further reduce the quantum noise by exploiting the quantum entanglement between the optical fields at the filter cavity two ports.

We study nuclear effects in charged current deep inelastic neutrino-iron scattering in the framework of a ${\chi }^2$ analysis of parton distribution functions (PDFs). We extract a set of iron PDFs and show that under reasonable assumptions it is possible to constrain the valence, light sea, and strange quark distributions. Our iron PDFs are used to compute $x_{Bj}$-dependent and $Q^2$-dependent nuclear correction factors for iron structure functions which are required in global analyses of free nucleon PDFs. We compare our results with nuclear correction factors from neutrino-nucleus scattering models and correction factors for ${\ell }^{\pm }$-iron scattering. We find that, except for very high $x_{Bj}$, our correction factors differ in both shape and magnitude from the correction factors of the models and charged-lepton scattering.

Estimates are made of ultrahigh energy neutrino cross sections based on an extrapolation to very small Bjorken $x$ of the logarithmic Froissart dependence in $x$ shown previously to provide an excellent fit to the measured proton structure function $F_2^p(x,Q^2)$ over a broad range of the virtuality $Q^2$. Expressions are obtained for both the neutral current and the charged current cross sections. Comparison with an extrapolation based on perturbative QCD shows good agreement for energies where both fit data, but our rates are as much as a factor of 10 smaller for neutrino energies above ${10}^9\mathrm{GeV}$, with important implications for experiments searching for extragalactic neutrinos.

Masses of fermions in the $SO(10)$ 16-plet are constructed using only the 10, 120, and $\overline{126}$ scalar multiplets. The mass matrices are restricted to be Hermitian and the theory is constructed to have certain assumed quark masses, charged lepton masses, and Cabibbo-Kobayashi-Maskawa (CKM) matrix in accord with data. The remaining free parameters are found by fitting to light neutrino masses and Maki-Nakagawa-Sakata (MNS) matrices result as predictions.