The minimal-energy $B=6$ solution of the Skyrme model is a static soliton with $D_{4d}$ symmetry. The symmetries of the solution imply that the quantum numbers of the ground state are the same as those of the lithium-6 nucleus. This identification is considered further by obtaining expressions for the mean charge radius and quadrupole moment, dependent only on the Skyrme model parameters $e$ (a dimensionless constant) and $F_{\pi }$ (the pion decay constant). The optimal values of these parameters have often been deliberated upon, and we propose, for $B>2$, changing them from those which are most commonly accepted. We obtain specific values for these parameters for $B=6$, by matching with properties of the lithium-6 nucleus. We find further support for the new values by reconsidering the $\alpha$-particle and deuteron as quantized $B=4$ and $B=2$ Skyrmions.

We propose two alternative formulations for a three-dimensional nonanticommutative superspace in which some of the fermionic coordinates obey Clifford anticommutation relations. For this superspace, we construct the supersymmetry generators satisfying standard anticommutation relations and the corresponding supercovariant derivatives. We formulate a scalar superfield theory in such a superspace and calculate its propagator. We also suggest a prescription for the introduction of interactions in such theories.

Chaos in the orbits of black hole pairs has by now been confirmed by several independent groups. While the chaotic behavior of binary black hole orbits is no longer argued, it remains difficult to quantify the importance of chaos to the evolutionary dynamics of a pair of comparable mass black holes. None of our existing approximations are robust enough to offer convincing quantitative conclusions in the most highly nonlinear regime. It is intriguing to note that, in three different approximations to a black hole pair built of a spinning black hole and a nonspinning companion, two approximations exhibit chaos and one approximation does not. The fully relativistic scenario of a spinning test mass around a Schwarzschild black hole shows chaos, as does the post-Newtonian Lagrangian approximation. However, the approximately equivalent post-Newtonian Hamiltonian approximation does not show chaos when only one body spins. It is well known in dynamical systems theory that one system can be regular while an approximately related system is chaotic, so there is no formal conflict. However, the physical question remains: Is there chaos for comparable mass binaries when only one object spins? We are unable to answer this question given the poor convergence of the post-Newtonian approximation to the fully relativistic system. A resolution awaits better approximations that can be trusted in the highly nonlinear regime.

We show that in IIB string theory and for $D1D5p$ black holes in ten dimensions the method of entropy function works. Despite the more complicated form of the Wald formula for $D1D5p$ black holes in ten dimensions, the entropy is given by the entropy function at its extremum point. We use this method for computing the entropy of $D1D5p$ system both at the level of supergravity and for its higher order ${\alpha }^{\prime 3}{R}^4$ corrections.

Magnetic field plays a very important role in many astronomical phenomena at various scales of the universe. It is no exception in the early universe. Since the energy density, pressure, and tension of the primordial magnetic field affect gravitational collapses of plasma, the formation of seeds for large-scale structures should be influenced by them. Here we numerically investigate the effects of stochastic primordial magnetic field on the seeds of large-scale structures in the universe in detail. We found that the amplitude ratio between the density spectra with and without PMF ($|P(k)/P_0(k)|$ at $k>0.2{\mathrm{Mpc}}^{-1}$) lies between 75% and 130% at present for the range of PMF strengths $0.5\mathrm{nG}<B_{\lambda }<1.0\mathrm{nG}$, depending on the spectral index of PMF and the correlation between the matter density and the PMF distributions.

We calculate the baryon asymmetry of the Universe resulting from the combination of higher-dimensional Lorentz-noninvariant $CPT$-odd operators and dimension five operators that induce the majorana mass for neutrinos. The strength of $CPT$-violating dimension five operators capable of producing the observed value of baryon abundance is directly related to neutrino masses and found to be in the trans-Planckian range $({10}^{-24}–{10}^{-22}){\mathrm{GeV}}^{-1}$. Confronting it with observational tests of Lorentz symmetry, we find that this range of $\mathrm{\text{Lorentz}}/CPT$ violation is strongly disfavored by the combination of the low-energy constraints and astrophysical data.

We analyze two kinds of matched filters for data output of a spherical resonant GW detector. In order to filter the data of a real sphere, a strategy is proposed, firstly using an omnidirectional inline filter, which is supposed to select periodograms with excitations, secondly by performing a directional filter on such selected periodograms, finding the wave arrival time, direction and polarization. We point out that, as the analytical simplifications occurring in the ideal 6 transducers TIGA sphere do not hold for a real sphere, using a 5 transducers configuration could be a more convenient choice.

We provide the first study of the Corrigan-Ramond extension of one massless flavor Quantum Chromo Dynamics at nonzero quark chemical potential. The goal here is to probe the baryon sector of this extension via the associated chemical potential. Since the extension requires the fermions to transform in the two index antisymmetric representation of the gauge group, one finds that the number of possible channels is richer than in the ’t Hooft limit. We first discuss the diquark channels and show that for a number of colors larger than 3 a new diquark channel appears. We then study the infinite number of color limit and show that the Fermi surface is unstable to the formation of the Deryagin-Grigoriev-Rubakov chiral waves. We discover, differently from the ’t Hooft limit, the possibility of a colored chiral wave breaking the color symmetry as well as translation invariance.

We show that all the parameters which destabilize the weak scale can be taken around the weak scale in the MSSM without conflicting with the SM Higgs mass bound set by LEP experiment. The essential point is that if the lightest $CP$-even Higgs $h$ in the MSSM has only a small coupling to $Z$ boson, $g_{ZZh}$, LEP cannot generate the Higgs sufficiently. In the scenario, the SM Higgs mass bound constrains the mass of the heaviest $CP$-even Higgs $H$ which has the SM like $g_{ZZH}$ coupling. However, it is easier to make the heaviest Higgs heavy by the effect of off-diagonal elements of the mass matrix of the $CP$-even Higgs because the larger eigenvalue of $2\times 2$ matrix becomes larger by introducing off-diagonal elements. Thus, the smaller stop masses can be consistent with the LEP constraints. Moreover, the two excesses observed at LEP Higgs search can naturally be explained as the signals of the MSSM Higgs $h$ and $H$ in this scenario. One of the most interesting results in the scenario is that all the Higgs in the MSSM have the weak scale masses. For example, the charged Higgs mass should be around 130 GeV. This looks inconsistent with the lower bound obtained by the $b\to s\gamma$ process as $m_{H^{\pm }}>350\mathrm{GeV}$. However, we show that the amplitude induced by the charged Higgs can naturally be compensated by that of the chargino if we take the mass parameters by which the little hierarchy problem can be solved. The point is that the both amplitudes have the same order of magnitudes when all the fields in the both loops have the same order of masses.

A recent HyperCP observation of three events in the decay ${\Sigma }^{+}\to p{\mu }^{+}{\mu }^{-}$ is suggestive of a new particle with mass 214.3 MeV. In order to confront models that contain a light Higgs boson with this observation, it is necessary to know the Higgs production rate in hyperon decay. The contribution to this rate from penguinlike two-quark operators has been considered before and found to be too large. We point out that there are additional four-quark contributions to this rate that could be comparable in size to the two-quark contributions, and that could bring the total rate to the observed level in some models. To this effect we implement the low-energy theorems that dictate the couplings of light Higgs bosons to hyperons at leading order in chiral perturbation theory. We consider the cases of scalar and pseudoscalar Higgs bosons in the standard model and in its two-Higgs-doublet extensions to illustrate the challenges posed by existing experimental constraints and suggest possible avenues for models to satisfy them.

Determinations of the size and shape of the interaction region from $k$-particle $(k=1,2,\dots )$ momentum distributions of identical particles are analyzed. The full group of transformations changing the single-particle density matrix without affecting any of the measurable momentum distributions is identified. The corresponding uncertainties in the inferred parameters of the interaction region are discussed.

We derive the asymptotic traveling-wave solutions of the nonlinear 1-dimensional Balitsky-Kovchegov QCD equation for rapidity evolution in momentum space, with 1-loop running coupling constant and equipped with the Balitsky-Kovchegov-Kuraev-Lipatov kernel at next-to-leading logarithmic accuracy, conveniently regularized by different resummation schemes. Traveling waves allow us to define “universality classes” of asymptotic solutions, i.e. independent of initial conditions and of the nonlinear damping. A dependence on the resummation scheme remains, which is analyzed in terms of geometric scaling properties.

We report the observation of $e^{+}{e}^{-}\to \varphi \eta$ near $\sqrt{s}=10.58\mathrm{GeV}$ with $6.5\sigma$ significance in the $K^{+}{K}^{-}\gamma \gamma$ final state in a data sample of $224{\mathrm{fb}}^{-1}$ collected by the BABAR experiment at the PEP-II $e^{+}{e}^{-}$ storage rings. We measure the restricted radiation-corrected cross section to be $\sigma (e^{+}{e}^{-}\to \varphi \eta )=2.1\pm 0.4(\mathrm{stat})\pm 0.1(\mathrm{syst})\mathrm{fb}$ within the range $|\cos {\theta }^{*}|<0.8$, where ${\theta }^{*}$ is the center-of-mass polar angle of the $\varphi$ meson. The $\varphi$ meson is required to be in the invariant mass range of $1.008<m_{\varphi }<1.035\mathrm{GeV}/c^2$. The radiation-corrected cross section in the full $\cos {\theta }^{*}$ range is extrapolated to be $2.9\pm 0.5(\mathrm{stat})\pm 0.1(\mathrm{syst})\mathrm{fb}$.

In this paper the internal structure of a neutron star is shown to be inferrable from its gravitational-wave spectrum. Iteratively applying the inverse scheme of the scaled coordinate logarithmic perturbation method for neutron stars proposed by Tsui and Leung [Astrophys. J. 631, 495 (2005)], we are able to determine the mass, the radius and the mass distribution of a star from its quasinormal mode frequencies of stellar pulsation. In addition, accurate equation of state of nuclear matter can be obtained from such inversion scheme. Explicit formulas for the case of axial $w$-mode oscillation are derived here and numerical results for neutron stars characterized by different equations of state are shown.

In this article, we present a numerical scheme for relativistic ideal hydrodynamics on arbitrary curved spacetimes in up to three spatial dimensions. The aim of this scheme is an improved treatment of stationary or quasistationary scenarios without loss of general applicability. This is achieved by treating pressure and gravitational forces, which are usually computed with unrelated numerical methods, within a unified framework. We derive a special formulation of the source terms in the hydrodynamic evolution equations, which is then utilized to construct the new scheme. For single star simulations, the optimizations take full effect only for rigidly rotating isentropic stars in a corotating coordinate frame. To test the algorithm, simulations of single polytropic neutron stars (rigidly rotating and nonrotating) have been carried out, demonstrating its usefulness for studies of stellar oscillation modes. We found that most of the numerical error is caused by the treatment of the stellar surface. To study the evolution scheme itself, we introduce a test bed involving an artificial spacetime without a fluid-vacuum boundary. The oscillation modes of the stellar models used here have already been investigated in the literature. A comparison with our results is given, exhibiting good agreement.

Einstein-Hilbert (EH) action can be separated into a bulk and a surface term, with a specific (“holographic”) relationship between the two, so that either can be used to extract information about the other. The surface term can also be interpreted as the entropy of the horizon in a wide class of spacetimes. Since EH action is likely to just the first term in the derivative expansion of an effective theory, it is interesting to ask whether these features continue to hold for more general gravitational actions. We provide a comprehensive analysis of Lagrangians of the form $\sqrt{-g}L=\sqrt{-g}Q_a{}^{bcd}R^a{}_{bcd}$, in which $Q_a{}^{bcd}$ is a tensor with the symmetries of the curvature tensor, made from metric and curvature tensor and satisfies the condition ${\nabla }_{c}Q_a{}^{bcd}=0$, and show that they share these features. The Lanczos-Lovelock Lagrangians are a subset of these in which $Q_a{}^{bcd}$ is a homogeneous function of the curvature tensor. They are all holographic, in a specific sense of the term, and—in all these cases—the surface term can be interpreted as the horizon entropy. The thermodynamics route to gravity, in which the field equations are interpreted as $TdS=dE+pdV$, seems to have a greater degree of validity than the field equations of Einstein gravity itself. The results suggest that the holographic feature of EH action could also serve as a new symmetry principle in constraining the semiclassical corrections to Einstein gravity. The implications are discussed.

The dynamical age of the universe depends upon the rate of the expansion of the universe, which explicitly involves the dark energy equation of state parameter $w(z)$. Consequently, the evolution of $w(z)$ has a direct imprint on the age of the universe. We have shown that the dynamical age of the universe as derived from CMB data can be used as an authentic criterion, being independent of the prior assumptions likethe present value of the Hubble constant $H_0$ and the cosmological density parameter ${\Omega }_M^0$, to constrain the range of admissible values of $w$ for quiessence models and to test the physically viable parametrizations of the equation of state $w(z)$ in kinessence models. An upper bound on variation of dark energy density is derived and a relation between cosmological density parameters and the transition redshift is established.

The existing and upcoming multiwavelength data from the galactic center suggest a comparative study in order to propose or rule out possible models which would explain the observations. In this paper we consider the x-ray synchrotron and the gamma-ray emission due to Kaluza-Klein dark matter and define a set of parameters for the shape of the dark matter halo which is consistent with the observations. We show that for this class of models the existing Chandra x-ray data are more restrictive than the constraints on very high energy gamma rays coming from HESS.

We present an analytical treatment of gravitational lensing by a Kerr black hole in the weak deflection limit. Lightlike geodesics are expanded as a Taylor series up to and including third-order terms in $m/b$ and $a/b$, where $m$ is the black hole mass, $a$ the angular momentum, and $b$ the impact parameter of the light ray. Positions and magnifications of individual images are computed with a perturbative analysis. At this order, the degeneracy with the translated Schwarzschild lens is broken. The critical curve is still a circle displaced from the black hole position in the equatorial direction and the corresponding caustic is pointlike. The degeneracy between the black hole spin and its inclination relative to the observer is broken through the angular coordinates of the perturbed images.

The result of a recent publication by M. Kachelrieß and D. Semikoz of a broad maximum around 25 degrees in the two-point autocorrelation function of ultrahigh energy cosmic ray arrival directions has been intriguingly interpreted as the first imprint of the large scale structures (LSS) of baryonic matter in the near universe. We analyze this suggestion in light of the clustering properties expected from the PSCz astronomical catalogue of LSS. The chance probability of the signal is consistent within $2\sigma$ with the predictions based on the catalogue. No evidence for a significant cross correlation of the observed events with known overdensities in the LSS is found, which may be due to the role of the galactic and extragalactic magnetic fields, and is however consistent with the limited statistics. The larger statistics to be collected by the Pierre Auger Observatory is needed to answer definitely the question.