We study the thermodynamics of de Sitter black holes with a conformally coupled scalar field. The geometry is that of the lukewarm Reissner-Nordström-de Sitter black holes, with the event and cosmological horizons at the same temperature. This means that the region between the event and cosmological horizons can form a regular Euclidean instanton. The entropy is modified by the nonminimal coupling of the scalar field to the geometry, but can still be derived from the Euclidean action, provided suitable modifications are made to deal with the electrically charged case. We use the first law as derived from the isolated horizons formalism to compute the local horizon energies for the event and cosmological horizons.

Quasiperiodic oscillations of high density thick accretion disks orbiting a Schwarzschild black hole have been recently addressed as interesting sources of gravitational waves. The aim of this paper is to compare the gravitational waveforms emitted from these sources when computed using (variations of) the standard quadrupole formula and gauge-invariant metric perturbation theory. To this goal we evolve representative disk models using an existing general relativistic hydrodynamics code which has been previously employed in investigations of such astrophysical systems. Two are the main results of this work: First, for stable and marginally stable disks, no excitation of the black hole quasinormal modes is found. Second, we provide a simple, relativistic modification of the Newtonian quadrupole formula which, in certain regimes, yields excellent agreement with the perturbative approach. This holds true as long as back-scattering of GWs is negligible. Otherwise, any functional form of the quadrupole formula yields systematic errors $\sim 10\%$.

We consider the constraints that can be imposed on a wide class of Inflation models in modified gravity scenarios in which the Friedmann equation is modified by the inclusion of ${\rho }^2$ terms, where $\rho$ is the total energy density. In particular we obtain the reheating temperature and gravitino abundance associated with the end of inflation. Whereas models of chaotic inflation and natural inflation can easily avoid the conventional gravitino overproduction problem, we show that supersymmetric hybrid inflation models (driven by both $F$ and $D$ terms) do not work in the ${\rho }^2$ dominated era. We also study inflation driven by exponential potentials in this modified background and show that the gravitino production is suppressed enough to avoid there being a problem, although other conditions severely constrain these models.

We study implications of the curvaton, a late-decaying light scalar field, on inflationary cosmology, paying particular attentions to modifications of observable quantities such as the scalar spectral index of the primordial power spectrum and the tensor-to-scalar ratio. We consider this issue from a general viewpoint and discuss how the observable quantities are affected by the existence of the curvaton. It is shown that the modification owing to the curvaton depends on class of inflation models. We also study the effects of the curvaton on inflation models generated by the inflationary flow equation.

We develop a theoretical method of constructing the quintessence potential directly from the effective equation of state function $w(z)$, which describes the properties of the dark energy. We apply our method to four parametrizations of equation of state parameter and discuss the general features of the resulting potentials. In particular, it is shown that the constructed quintessence potentials are all in the form of a runaway type.

The large scale dynamics of the universe appears to be dominated by a “dark energy” constituent with negative pressure to density ratio $w=P/\rho$, which could be stable if sufficiently rigid, but not if purely fluid. It was suggested by Bucher and Spergel that such a cosmological solid might be constituted by a cold (static) distribution of cosmic strings with $w=-1/3$, or membranes with the observationally more favored value $w=-2/3$, but it was not shown that the rigidity actually would be sufficient for stability. For cases in which the defect lattice is formed from even junctions, it is found that the rigidity to density ratio will be given by $\mu /\rho =4/15$ in both the string and membrane cases, and it is confirmed that this is indeed sufficient for stabilisation with respect to sufficiently small perturbations.

We consider the effects of the curvaton, late-decaying scalar condensation, to observational constraints on inflation models. From current observations of cosmic density fluctuations, severe constraints on some classes of inflation models are obtained, in particular, on the chaotic inflation with higher-power monomials, the natural inflation, and the new inflation. We study how the curvaton scenario changes (and relaxes) the constraints on these models.

We address a number of issues raised by a manuscript of Klein, Toublan, and Verbaarschot [hep-ph/0405180] in which the authors introduce a random matrix model for QCD with two colors, two flavors, and fermions in the fundamental representation. Their inclusion of temperature terms differs from the approach adopted in previous work on this problem [Phys. Rev. D 64, 074016 (2001)]. We demonstrate that the two approaches are related by a transformation that leaves the thermodynamic potential invariant and which therefore has no effect on physical observables.

The physics of moduli fields is examined in the scenario where the gravitino is relatively heavy with mass of order 10 TeV, which is favored in view of the severe gravitino problem. The form of the moduli superpotential is shown to be determined, if one imposes a phenomenological requirement that no physical $CP$ phase arise in gaugino masses from conformal anomaly mediation. This bottom-up approach allows only two types of superpotential, each of which can have its origins in a fundamental underlying theory such as superstring. One superpotential is the sum of an exponential and a constant, which is identical to that obtained by Kachru et al. (KKLT), and the other is the racetrack superpotential with two exponentials. The general form of soft supersymmetry-breaking masses is derived, and the pattern of the superparticle mass spectrum in the minimal supersymmetric standard model is discussed with the KKLT-type superpotential. It is shown that the moduli mediation and the anomaly mediation make comparable contributions to the soft masses. At the weak scale, the gaugino masses are rather degenerate compared to the minimal supergravity, which bring characteristic features on the superparticle masses. In particular, the lightest neutralino, which often constitutes the lightest superparticle and thus a dark matter candidate, is a considerable admixture of gauginos and Higgsinos. We also find a small mass hierarchy among the moduli, gravitino, and superpartners of the standard-model fields. Cosmological implications of the scenario are briefly described.

We present new measurements of $CP$-violation parameters in $B^0\to \varphi K^0$, $K^{+}{K}^{-}{K}_S^0$, $f_0(980)K_S^0$, ${\eta }^{\prime }{K}_S^0$, $\omega K_S^0$, and $K_S^0{\pi }^0$ decays based on a sample of $275\times {10}^6$ $B\overline{B}$ pairs collected at the ${\rm Y}(4S)$ resonance with the Belle detector at the KEKB energy-asymmetric $e^{+}{e}^{-}$ collider. One neutral $B$ meson is fully reconstructed in one of the specified decay channels, and the flavor of the accompanying $B$ meson is identified from its decay products. $CP$-violation parameters for each of the decay modes are obtained from the asymmetries in the distributions of the proper-time intervals between the two $B$ decays. The combined result for the $B^0\to \varphi K^0$, $K^{+}{K}^{-}{K}_S^0$, $f_0(980)K_S^0$, ${\eta }^{\prime }{K}_S^0$, $\omega K_S^0$, $K_S^0{\pi }^0$, and previously reported $K_S^0{K}_S^0{K}_S^0$ decays differs from the SM expectation by 2.4 standard deviations.

Generalizing earlier results on dust collapse in higher dimensions, we show here that cosmic censorship can be restored in some classes of gravitational collapse models with tangential pressure present, if we take the spacetime dimension to be $N\ge 6$. This is under conditions to be motivated physically, such as smoothness of initial data from which the collapse develops. The models considered here with nonzero pressure include the Einstein cluster spacetimes which have been earlier studied extensively. Our work provides a step towards an understanding of the cosmic censorship conjecture and the necessary conditions for its validity.

Lagrangian perturbation theory for cosmological fluid describes structure formation in the quasinonlinear stage well. In a previous paper, we presented a third-order perturbative equation for Lagrangian perturbation with pressure. There we considered only the longitudinal modes for the first-order perturbation. In this paper, we generalize the perturbation, i.e., we consider both the longitudinal and the transverse modes for the first-order perturbation. Then we derive third-order perturbative equations and solutions.

Axion-photon conversion induced by intergalactic magnetic fields has been proposed as an explanation for the dimming of distant supernovae of type Ia (SNe Ia) without cosmic acceleration. The effect depends on the intergalactic electron density $n_e$ as well as the $B$-field strength and domain size. We show that for $n_e\lesssim {10}^{-9}{\mathrm{cm}}^{-3}$ the same mechanism would cause excessive spectral distortion of the cosmic microwave background (CMB). This small-$n_e$ parameter region had been left open by the most restrictive previous constraints based on the dispersion of quasar (QSO) spectra. The combination of CMB and QSO limits suggests that the photon-axion conversion mechanism can only play a subleading role for SN Ia dimming. A combined analysis of all the observables affected by the photon-axion oscillations would be required to give a final verdict on the viability of this model.

One of the greatest data analysis challenges for the Laser Interferometer Space Antenna (LISA) is the need to account for a large number of gravitational wave signals from compact binary systems expected to be present in the data. We introduce the basis of a Bayesian method that we believe can address this challenge and demonstrate its effectiveness on a simplified problem involving 100 synthetic sinusoidal signals in noise. We use a reversible jump Markov chain Monte Carlo technique to infer simultaneously the number of signals present, the parameters of each identified signal, and the noise level. Our approach therefore tackles the detection and parameter estimation problems simultaneously, without the need to evaluate formal model selection criteria, such as the Akaike Information Criterion or explicit Bayes factors. The method does not require a stopping criterion to determine the number of signals and produces results which compare very favorably with classical spectral techniques.

A search for the decay of the $\tau$ lepton to seven charged pions and one or zero ${\pi }^0$ mesons was performed using the BABAR detector at the PEP-II asymmetric-energy $e^{+}{e}^{-}$ collider. The analysis uses $232.2{\mathrm{fb}}^{-1}$ of data at center-of-mass energies on or near the ${\rm Y}(4S)$ resonance. We observe 24 events with an expected background of $21.6\pm 1.3$ events. Without evidence for a signal, we calculate an upper limit of $\mathcal{B}$$({\tau }^{-}\to 4{\pi }^{-}3{\pi }^{+}({\pi }^0){\nu }_{\tau })<3.0\times {10}^{-7}$ at 90% confidence level. This is an improvement by nearly an order of magnitude over the previously established limit. In addition, we set upper limits for the exclusive decays ${\tau }^{-}\to 4{\pi }^{-}3{\pi }^{+}{\nu }_{\tau }$ and ${\tau }^{-}\to 4{\pi }^{-}3{\pi }^{+}{\pi }^0{\nu }_{\tau }$.

We complete an earlier derivation of the 4-point bosonic scattering amplitudes, and of the corresponding linearized local supersymmetric invariants in $D=11$ supergravity, by displaying the form-curvature, $F^2{R}^2$, terms.

Oscillatons are solutions of the coupled Einstein-Klein-Gordon equations that are globally regular and asymptotically flat. By means of a Legendre transformation we are able to visualize the behavior of the corresponding objects in nonlinear gravity where the scalar field has been absorbed by means of the conformal mapping.

The relativistic five-quark equations are found in the framework of the dispersion relation technique. The solutions of these equations using the method based on the extraction of the leading singularities of the amplitudes are obtained. The five-quark amplitudes for the low-lying pentaquarks including the $u$, $d$, $s$ quarks are calculated. The poles of these amplitudes determine the masses of the negative parity pentaquarks with $I=0,1$ and $J^P={\frac{3}{2}}^{-},{\frac{5}{2}}^{-}$. The mass of the lowest pentaquark with $I=0$ and $J^P={\frac{3}{2}}^{-}$ is equal to 1514 MeV.

We compare results of four public supersymmetric spectrum codes, ISAJET 7.71, SOFTSUSY 1.9, SPHENO 2.2.2 and SUSPECT 2.3 to estimate the present-day uncertainty in the calculation of the relic density of dark matter in minimal supergravity models. We find that even for mass differences of about 1% the spread in the obtained relic densities can be 10%. In difficult regions of the parameter space, such as large $\tan \beta$ or large $m_0$, discrepancies in the relic density are much larger. We also find important differences in the stau coannihilation region. We show the impact of these uncertainties on the bounds from Wilkinson Microwave Anisotropy Probe for several scenarios, concentrating on the regions of parameter space most relevant for collider phenomenology. We also discuss the case of $A_0\ne 0$ and the stop coannihilation region. Moreover, we present a World Wide Web application for the online comparison of the spectrum codes.

We study $N=2$ supersymmetric quantum mechanics of a charged particle on sphere in the background of Dirac magnetic monopole. We adopt $CP(1)$ model approach in which the monopole interaction is free of singularity. It turns out that this approach admits a compact $N=2$ superspace formulation. In order to exploit manifest U(1) covariance in the superspace formalism, we introduce a gauged chiral superfield which is annihilated by the gauge covariant superderivative instead of the usual superderivative. We carry out the Dirac quantization of the resulting system and compute the quantum mechanical spectrum. We obtain the condition for the spontaneous breaking of supersymmetry explicitly in terms of the monopole charge and a parameter which characterizes the operator ordering ambiguity. We find that the supersymmetry is spontaneously broken unless a certain combination of these quantities satisfies some quantization condition.