We present a detailed description of high-energy neutrino and antineutrino inelastic inclusive scattering off nuclei in terms of nuclear structure functions. In our approach we take into account a QCD description of the nucleon structure functions as well as a number of basic nuclear effects including nuclear shadowing, Fermi motion and binding, nuclear pion excess, and off-shell correction to bound nucleon structure functions. These effects prove to be important in the studies of charged-lepton deep-inelastic scattering. We discuss similarities and dissimilarities in the calculation of nuclear effects for charged-lepton and neutrino scattering caused by a nonconserved axial current in neutrino scattering. We examine the Adler and the Gross-Llewellyn-Smith sum rules for nuclear structure functions and find a remarkable cancellation between nuclear shadowing and off-shell corrections in these sum rules. We present calculations of differential cross sections for inclusive neutrino and antineutrino scattering in comparison with recent data on different target materials.

The four-quark system $c\overline{c}n\overline{n}$ is studied in the framework of the constituent quark model. Using different types of quark-quark potentials, we solve the four-body Schrödinger equation by means of the hyperspherical harmonic formalism. Exploring the low laying $J^{\mathrm{PC}}$ states for different isospin configurations no four-quark bound states have been found. Of particular interest is the possible four-quark structure of the $X(3872)$. We rule out the possibility that this particle is a compact tetraquark system, unless additional correlations, either in the form of diquarks or at the level of the interacting potential, not considered in simple quark models do contribute.

In view of the recent results from the MiniBooNE experiment we revisit the global neutrino oscillation fit to short-baseline neutrino data by adding one or two sterile neutrinos with eV-scale masses to the three standard model neutrinos, and for the first time we consider also the global fit with three sterile neutrinos. Four-neutrino oscillations of the ($3+1$) type have been only marginally allowed before the recent MiniBooNE results, and become even more disfavored with the new data (at the level of $4\sigma$). In the framework of so-called ($3+2$) five-neutrino mass schemes we find severe tension between appearance and disappearance experiments at the level of more than $3\sigma$, and hence no satisfactory fit to the global data is possible in ($3+2$) schemes. This tension remains also when a third sterile neutrino is added, and the quality of the global fit does not improve significantly in a ($3+3$) scheme. It should be noted, however, that in models with more than one sterile neutrino the MiniBooNE results are in perfect agreement with the appearance evidence reported by the LSND Collaboration, thanks to the possibility of $CP$ violation available in such oscillation schemes. Furthermore, if disappearance data are not taken into account ($3+2$) oscillations provide an excellent fit to the full MiniBooNE spectrum including the event excess at low energies.

With a sample of $232\times {10}^6$ $\mathit{{\rm Y}}(4S)\to B\overline{B}$ events collected with the BABAR detector, we study the decays of $B$ mesons to $p\overline{p}h$ final states, where $h={\pi }^{+}$, $K_S^0$, $K^{*0}$, or $K^{*+}$. We report evidence for the $B^0\to p\overline{p}{K}^{*0}$ decay, with a branching fraction $(1.47\pm 0.45(\mathrm{stat})\pm 0.40(\mathrm{syst}))\times {10}^{-6}$, and for the $B^{+}\to {\eta }_c{K}^{*+}$ decay, with the branching fraction of $\mathcal{B}(B^{+}\to {\eta }_c{K}^{*+})\times \mathcal{B}({\eta }_c\to p\overline{p})=({1.57}_{-0.45}^{+0.56}(\mathrm{stat}{)}_{-0.36}^{+0.46}(\mathrm{syst}))\times {10}^{-6}$, and provide improved measurements of the branching fractions of the other modes of this type. We also report the measurements of the charge asymmetry consistent with zero in the $B^{+}\to p\overline{p}{\pi }^{+}$, $B^0\to p\overline{p}{K}^{*0}$, and $B^{+}\to p\overline{p}{K}^{*+}$ modes. No evidence is found for the pentaquark candidate ${\Theta }^{+}$ in the mass range 1.52 to $1.55\mathrm{GeV}/c^2$, decaying into $p{K}_S^0$, or the glueball candidate $f_J(2220)$ in the mass range $2.2<m_{p\overline{p}}<2.4\mathrm{GeV}/c^2$, and branching fraction limits are established for both at the ${10}^{-7}$ level.

The Newman-Unti formalism of the Kerr-Newman metric near future null infinity is developed, with which the Newman-Penrose constants for both the gravitational and electromagnetic fields of the Kerr-Newman metric are computed and shown to be zero. The multipole structure near future null infinity in the sense of Janis-Newman of the Kerr-Newman metric is then further studied. It is found that up to the $2^4$-pole, modulo a constant dependent upon the order of the pole, these multipole moments agree with those of Geroch-Hansen multipole moments defined at spatial infinity.

Explicit Calabi-Yau metrics are derived that are argued to map to the Maldacena-Nuñez AdS solutions of M-theory and IIB under geometric transitions. In each case the metrics are singular where a $H^2$ Kähler two-cycle degenerates but are otherwise smooth. They are derived as the most general Calabi-Yau solutions of an ansatz for the supergravity description of branes wrapped on Kähler two-cycles. The ansatz is inspired by rewriting the AdS solutions, and the structure defined by half their Killing spinors, in this form. The world-volume theories of fractional branes wrapped at the singularities of these metrics are proposed as the duals of the AdS solutions. The existence of supergravity solutions interpolating between the AdS and Calabi-Yau metrics is conjectured and their boundary conditions briefly discussed.

We compute the shear viscosity at leading order in hot quantum electrodynamics. Starting from the Kubo relation for shear viscosity, we use diagrammatic methods to write down the appropriate integral equations for bosonic and fermionic effective vertices. We also show how Ward identities can be used to put constraints on these integral equations. One of our main results is an equation relating the kernels of the integral equations with functional derivatives of the full self-energy; it is similar to what is obtained with two-particle-irreducible effective action methods. However, since we use Ward identities as our starting point, gauge invariance is preserved. Using these constraints obtained from Ward identities and also power counting arguments, we select the necessary diagrams that must be resummed at leading order. This includes all noncollinear (corresponding to 2 to 2 scatterings) and collinear (corresponding to $1+\mathrm{N}$ to $2+\mathrm{N}$ collinear scatterings) rungs responsible for the Landau-Pomeranchuk-Migdal effect. We also show the equivalence between our integral equations obtained from quantum field theory and the linearized Boltzmann equations of Arnold, Moore and Yaffe obtained using effective kinetic theory.

We derive the most general Seiberg-Witten maps for noncommutative gauge theories in second order of the noncommutative parameter $\theta$. Our results reveal the existence of more ambiguities than previously known. In particular, we demonstrate that some of these ambiguities enter observables like scattering cross sections and enlarge the parameter space of the noncommutative standard model beyond $\mathcal{O}(\theta )$.

We derive general constraints on the relic abundances of a long-lived particle which mainly decays into a neutrino (and something else) at cosmological time scales. Such an exotic particle may show up in various particle-physics models based on physics beyond the standard model. The constraints are obtained from big bang nucleosynthesis, cosmic microwave background, and diffuse neutrino and photon fluxes, depending on the lifetime and the electromagnetic and hadronic branching ratios.

We propose a new method to study the quasinormal modes of rotating relativistic stars. Oscillations are treated as perturbations in the frequency domain of the stationary, axisymmetric background describing a rotating star. The perturbed quantities are expanded in circular harmonics, and the resulting 2D equations they satisfy are integrated using spectral methods in the $(r,\theta )$ plane. The asymptotic conditions at infinity, needed to find the mode frequencies, are implemented by generalizing the standing wave boundary condition commonly used in the nonrotating case. As a test, the method is applied to find the quasinormal mode frequencies of a slowly rotating star.

A solution-generating technique is developed for $D=5$ minimal supergravity with two commuting Killing vectors based on the $G_2$ $U$-duality arising in the reduction of the theory to three dimensions. The target space of the corresponding 3-dimensional sigma model is the coset $G_{2(2)}/[SL(2,R)\times SL(2,R)]$. Its isometries constitute the set of solution-generating symmetries. These include two electric and two magnetic Harrison transformations with the corresponding two pairs of gauge transformations, three $SL(2,R)$ $S$-duality transformations, and the three gravitational scale, gauge, and Ehlers transformations (altogether 14). We construct a representation of the coset in terms of $7\times 7$ matrices realizing the automorphisms of split octonions. Generating a new solution amounts to transforming the coset matrices by one-parametric subgroups of $G_{2(2)}$ and subsequently solving the dualization equations. Using this formalism we derive a new charged black ring solution with two independent parameters of rotation.

We calculate the quasinormal modes of black holes localized on a 3-brane of finite tension embedded in six-dimensional flat spacetime. Using the WKB approximation, we obtain the frequencies of scalar and gravitational perturbations both analytically and numerically for arbitrary brane tension. We thus extend earlier analytical results which were derived for a brane of small tension.

We examine the Schwarzschild interior of a black hole, incorporating quantum gravitational modifications due to loop quantum gravity. We consider an improved loop quantization using techniques that have proven successful in loop quantum cosmology. The central Schwarzschild singularity is resolved and the implications for the fate of an in-falling test particle in the interior region is discussed. The singularity is replaced by a Nariai type universe. We discuss the resulting conformal diagram, providing a clear geometrical interpretation of the quantum effects.

It is well-entrenched folklore that all torsion gravity theories predict observationally negligible torsion in the solar system, since torsion (if it exists) couples only to the intrinsic spin of elementary particles, not to rotational angular momentum. We argue that this assumption has a logical loophole which can and should be tested experimentally, and consider nonstandard torsion theories in which torsion can be generated by macroscopic rotating objects. In the spirit of $\mathrm{\text{action}}=\mathrm{\text{reaction}}$, if a rotating mass like a planet can generate torsion, then a gyroscope would be expected to feel torsion. An experiment with a gyroscope (without nuclear spin) such as Gravity Probe B (GPB) can test theories where this is the case. Using symmetry arguments, we show that to lowest order, any torsion field around a uniformly rotating spherical mass is determined by seven dimensionless parameters. These parameters effectively generalize the parametrized post-Newtonian formalism and provide a concrete framework for further testing Einstein’s general theory of relativity (GR). We construct a parametrized Lagrangian that includes both standard torsion-free GR and Hayashi-Shirafuji maximal torsion gravity as special cases. We demonstrate that classic solar system tests rule out the latter and constrain two observable parameters. We show that Gravity Probe B is an ideal experiment for further constraining nonstandard torsion theories, and work out the most general torsion-induced precession of its gyroscope in terms of our torsion parameters.

Inflationary predictions based on the linear theory of cosmological perturbations are related to the two-point function of a (second quantized) real scalar free field during the accelerated stage. Such a two-point function is finite, in contrast with its coincidence limit, which is divergent due to the ultraviolet divergences proper of field theory. We therefore argue that predictions of most of the inflationary models do not necessarily need a regularization scheme to leading order, i.e. tree level, which is required instead for nonlinear corrections or calculations involving the energy-momentum tensor. We also discuss unpleasant features for the spectrum on demanding its regularization by the traditional fourth order adiabatic subtraction.

We present general relativistic correction terms appearing in Newton’s gravity to the second-order perturbations of cosmological fluids. In our previous work we have shown that to the second-order perturbations, the density and velocity perturbation equations of general relativistic zero-pressure, irrotational, single-component fluid in a spatially flat background coincide exactly with the ones known in Newton’s theory without using the gravitational potential. We also have shown the effect of gravitational waves to the second order, and pure general relativistic correction terms appearing in the third-order perturbations. Here, we present results of second-order perturbations relaxing all the assumptions made in our previous works. We derive the general relativistic correction terms arising due to (i) pressure, (ii) multicomponent, (iii) background spatial curvature, and (iv) rotation. In the case of multicomponent zero-pressure, irrotational fluids under the flat background, we effectively do not have relativistic correction terms, thus the relativistic equations expressed in terms of density and velocity perturbations again coincide with the Newtonian ones. In the other three cases we generally have pure general relativistic correction terms. In the case of pressure, the relativistic corrections appear even in the level of background and linear perturbation equations. In the presence of background spatial curvature, or rotation, pure relativistic correction terms directly appear in the Newtonian equations of motion of density and velocity perturbations to the second order; to the linear order, without using the gravitational potential (or metric perturbations), we have relativistic/Newtonian correspondences for density and velocity perturbations of a single-component fluid including the rotation even in the presence of background spatial curvature. In the small-scale limit (far inside the horizon), to the second-order, relativistic equations of density and velocity perturbations including the rotation coincide with the ones in Newton’s gravity. All equations in this work include the cosmological constant in the background world model. We emphasize that our relativistic/Newtonian correspondences in several situations and pure general relativistic corrections in the context of Newtonian equations are mainly about the dynamic equations of density and velocity perturbations without using the gravitational potential (metric perturbations). Consequently, our relativistic/Newtonian correspondences do not imply the absence of many space-time (i.e., pure general relativistic) effects like frame dragging, and redshift and deflection of photons even in such cases. We also present the case of multiple minimally coupled scalar fields, and properly derive the large-scale conservation properties of curvature perturbation variable in various temporal gauge conditions to the second order.

Motivated by our earlier work, we analyze how the inflaton decay reheats the Universe within supersymmetry. In a nonsupersymmetric case the inflaton usually decays via preheating unless its couplings to other fields are very small. Naively one would expect that supersymmetry enhances bosonic preheating as it introduces new scalars such as squarks and sleptons. On the contrary, we point out that preheating is unlikely within supersymmetry. The reason is that flat directions in the scalar potential, classified by gauge-invariant combinations of slepton and squark fields, are generically displaced towards a large vacuum expectation value (VEV) in the early Universe. They induce supersymmetry preserving masses to the inflaton decay products through the standard model Yukawa couplings, which kinematically blocks preheating for $\mathrm{VEVs}>{10}^{13}\mathrm{GeV}$. The decay will become allowed only after the flat directions start oscillating, and once the flat direction VEV is sufficiently redshifted. For models with weak scale supersymmetry, this generically happens at a Hubble expansion rate: $H\simeq ({10}^{-3}–{10}^{-1})\mathrm{TeV}$, at which time the inflaton decays in the perturbative regime. This is to our knowledge the first analysis where the inflaton decay to the standard model particles is treated properly within supersymmetry. There are a number of important consequences: no overproduction of dangerous supersymmetric relics (particularly gravitinos), no resonant excitation of superheavy dark matter, and no nonthermal leptogenesis through nonperturbative creation of the right-handed (s)neutrinos. Finally supersymmetric flat directions can even spoil hybrid inflation altogether by not allowing the auxiliary field to become tachyonic.

We introduce the redshift spherical shell energy, which can be used to test in the redshift space the radial inhomogeneity of an isotropic universe, providing additional constraints for Lemaitre-Tolman-Bondi models, and a more general test of cosmic homogeneity.

Matched filtering is used to search for gravitational waves emitted by inspiralling compact binaries in data from the ground-based interferometers. One of the key aspects of the detection process is the design of a template bank that covers the astrophysically pertinent parameter space. In an earlier paper, we described a template bank that is based on a square lattice. Although robust, we showed that the square placement is overefficient, with the implication that it is computationally more demanding than required. In this paper, we present a template bank based on an hexagonal lattice, which size is reduced by 40% with respect to the proposed square placement. We describe the practical aspects of the hexagonal template bank implementation, its size, and computational cost. We have also performed exhaustive simulations to characterize its efficiency and safeness. We show that the bank is adequate to search for a wide variety of binary systems (primordial black holes, neutron stars, and stellar-mass black holes) and in data from both current detectors (initial LIGO, Virgo and GEO600) as well as future detectors (advanced LIGO and EGO). Remarkably, although our template bank placement uses a metric arising from a particular template family, namely, stationary phase approximation, we show that it can be used successfully with other template families (e.g., Padé resummation and effective one-body approximation). This quality of being effective for different template families makes the proposed bank suitable for a search that would use several of them in parallel (e.g., in a binary black hole search). The hexagonal template bank described in this paper is currently used to search for nonspinning inspiralling compact binaries in data from the Laser Interferometer Gravitational-Wave Observatory (LIGO).

The low frequency sensitivity of space-borne gravitational wave observatories will depend critically on the geodesic purity of the trajectories of orbiting test masses. Fluctuations in the temperature difference across the enclosure surrounding the free-falling test mass can produce noisy forces through several processes, including the radiometric effect, radiation pressure, and outgassing. We present here a detailed experimental investigation of thermal gradient-induced forces for the Laser Interferometer Space Antenna (LISA) gravitational wave mission and the LISA Pathfinder, employing high resolution torsion pendulum measurements of the torque on a LISA-like test mass suspended inside a prototype of the LISA gravitational reference sensor that will surround the test mass in orbit. The measurement campaign, accompanied by numerical simulations of the radiometric and radiation pressure effects, allows a more accurate and representative characterization of thermal-gradient forces in the specific geometry and environment relevant to LISA free-fall. The pressure dependence of the measured torques allows clear identification of the radiometric effect, in quantitative agreement with the model developed. In the limit of zero gas pressure, the measurements are most likely dominated by outgassing, but at a low level that does not threaten the current LISA noise estimate, which assumes a maximum net force per degree of temperature difference of $100\frac{pN}{K}$ for the overall thermal gradient-induced effects.