Thermally relativistic flows in the early Universe can be characterized by the emergence of flows induced by gravitational-force-free particle motion in curved spacetime as well as induced by the gravitational force. In this paper, thermally relativistic flows induced by gravitational-force-free particle motion in curved spacetime are discussed on the basis of the general relativistic Boltzmann equation. As an object of analysis, we consider the flow from the static state inside the Schwarzschild radius of a thermally relativistic stuffed black hole induced by such motion. Analytical results obtained using the collisionless, nongravitational general relativistic Boltzmann equation reveal that the initial cluster is induced by gravitational-force-free particle motion. Numerical results obtained using the nongravitational general relativistic Anderson-Witting model confirm the presence of an initial cluster inside the thermally relativistic stuffed black hole, which is induced by gravitational-force-free particle motion.

In this paper we study the entropy perturbations in N-flation by using the $\delta \mathcal{N}$ formalism. We calculate the entropy corrections to the power spectrum of the overall curvature perturbation $P_{\zeta }$. We obtain an analytic form of the transfer coefficient $T_{\mathcal{R}\mathcal{S}}^2$, which describes the correlation between the curvature and entropy perturbations, and investigate its behavior numerically. It turns out that the entropy perturbations cannot be neglected in N-flation because the amplitude of entropy components is approximately in the same order as the adiabatic one at the end of inflation $T_{\mathcal{R}\mathcal{S}}^2\sim \mathcal{O}(1)$. The spectral index $n_S$ is calculated and it becomes smaller after the entropy modes are taken into account, i.e., the spectrum becomes redder, compared to the pure adiabatic case. Finally we study the modified consistency relation of N-flation, and find that the tensor-to-scalar ratio ($r\simeq 0.006$) is greatly suppressed by the entropy modes, compared to the pure adiabatic one ($r\simeq 0.017$) at the end of inflation.

When using distance measurements to probe spatial curvature, the geometric degeneracy between curvature and dark energy in the distance-redshift relation typically requires either making strong assumptions about the dark energy evolution or sacrificing precision in a more model-independent approach. Measurements of the redshift evolution of the linear growth of perturbations can break the geometric degeneracy, providing curvature constraints that are both precise and model independent. Future supernova, CMB, and cluster data have the potential to measure the curvature with an accuracy of $\sigma ({\Omega }_K)=0.002$, without specifying a particular dark energy phenomenology. In combination with distance measurements, the evolution of the growth function at low redshifts provides the strongest curvature constraint if the high-redshift universe is well approximated as being purely matter dominated. However, in the presence of early dark energy or massive neutrinos, the precision in curvature is reduced due to additional degeneracies, and precise normalization of the growth function relative to recombination is important for obtaining accurate constraints. Curvature limits from distances and growth compare favorably to other approaches to curvature estimation proposed in the literature, providing either greater accuracy or greater freedom from dark energy modeling assumptions, and are complementary due to the use of independent data sets. Model-independent estimates of curvature are critical both for testing inflation and for obtaining unbiased constraints on dark energy parameters.

We constrain the primordial non-Gaussianity parameter of the local model $f_{\mathrm{NL}}$ using the skewness power spectrum associated with the two-to-one cumulant correlator of cosmic microwave background temperature anisotropies. This bispectrum-related power spectrum was constructed after weighting the temperature map with the appropriate window functions to form an estimator that probes the multipolar dependence of the underlying bispectrum associated with the primordial non-Gaussianity. We also estimate a separate skewness power spectrum sensitive more strongly to unresolved point sources. When compared to previous attempts at measuring the primordial non-Gaussianity with WMAP data, our estimators have the main advantage that we do not collapse information to a single number. When model fitting the two-to-one skewness power spectrum, we make use of bispectra generated by the primordial non-Gaussianity, radio point sources, and lensing-secondary correlation. We analyze $Q$, $V$, and $W$-band WMAP 5-year data using the KQ75 mask out to $l_{\max }=600$. Using $V$ and $W$-band data and marginalizing over model parameters related to point sources and lensing-secondary bispectrum, our overall and preferred constraint on $f_{\mathrm{NL}}$ is $11.0\pm 23.7$ at the 68% confidence level ($-36.4<f_{\mathrm{NL}}<58.4$ at 95% confidence). We find no evidence for a nonzero value of $f_{\mathrm{NL}}$ even marginally at the $1\sigma$ level.

While it is well known that neutrinos are emitted from standard core collapse protoneutron star supernovae, less attention has been focused on neutrinos from accretion disks. These disks occur in some supernovae (i.e. collapsars) as well as in compact object mergers, and they emit neutrinos with similar properties to those from protoneutron star supernovae. These disks and their neutrinos play an important role in our understanding of gamma ray bursts as well as the nucleosynthesis they produce. We study a disk that forms in the merger of a black hole and a neutron star and examine the neutrino fluxes, luminosities and neutrino surfaces for the disk. We also estimate the number of events that would be registered in current and proposed supernova neutrino detectors if such an event were to occur in the Galaxy.

We present a maximum-likelihood analysis for estimating the angular distribution of power in an anisotropic stochastic gravitational-wave background using ground-based laser interferometers. The standard isotropic and gravitational-wave radiometer searches (optimal for point sources) are recovered as special limiting cases. The angular distribution can be decomposed with respect to any set of basis functions on the sky, and the single-baseline, cross-correlation analysis is easily extended to a network of three or more detectors—that is, to multiple baselines. A spherical-harmonic decomposition, which provides maximum-likelihood estimates of the multipole moments of the gravitational-wave sky, is described in detail. We also discuss (i) the covariance matrix of the estimators and its relationship to the detector response of a network of interferometers, (ii) a singular-value decomposition method for regularizing the deconvolution of the detector response from the measured sky map, (iii) the expected increase in sensitivity obtained by including multiple baselines, and (iv) the numerical results of this method when applied to simulated data consisting of both pointlike and diffuse sources. Comparisions between this general method and the standard isotropic and radiometer searches are given throughout, to make contact with the existing literature on stochastic background searches.

The asymmetric Higgs sector of one $SU(2{)}_L\times SU(2{)}_R$ bidoublet $({\varphi }_1^0,{\varphi }_1^{-};{\varphi }_2^{+},{\varphi }_2^0)$ and one $SU(2{)}_R$ doublet [but no $SU(2{)}_L$ doublet] is considered in a nonsupersymmetric left-right extension of the standard model of particle interactions. The inverse seesaw mechanism for neutrino mass is naturally implemented with the addition of fermion singlets, allowing thereby the possibility of breaking $SU(2{)}_R$ at the TeV scale. Flavor-changing neutral Higgs couplings to quarks are studied in two scenarios, where the $SU(2{)}_R$ charged-current mixing matrix is given either by the Cabibbo-Kobayashi-Maskawa matrix$V_R=V_{\mathrm{CKM}}$ (scenario I) or $V_R=1$ (scenario II). We consider the bounds on these scalar particle masses from $K-\overline{K}$ and $B-\overline{B}$ mixing, as well as $b\to s\gamma$. We find that, whereas in scenario I, they are of order 10 TeV, as in other left-right models, they may be well below 1 TeV in scenario II, thus allowing them to be within reach of detection at the forthcoming Large Hadron Collider.

We study exclusive nonleptonic two-body $B_c\to (D_{(s)},{\eta }_c,B_{(s)})+F$ decays with $F$ (pseudoscalar or vector mesons) factored out in the QCD factorization approach. The nonleptonic decay amplitudes are related to the product of meson decay constants and the form factors for semileptonic $B_c$ decays. As inputs in obtaining the branching ratios for a large set of nonleptonic $B_c$ decays, we use the weak form factors for the semileptonic $B_c\to (D_{(s)},{\eta }_c,B_{(s)})$ decays in the whole kinematical region and the unmeasured meson decay constants obtained from our previous light-front quark model. We compare our results for the branching ratios with those of other theoretical studies.

We reexamine the scale dependence of twist-three correlation functions relevant for the single transverse spin asymmetry in the framework of collinear factorization. Evolution equations are derived for both the flavor-nonsinglet and flavor-singlet distributions and arbitrary parton momenta. Our results do not agree with the recent calculations of the evolution in the limit of vanishing gluon momentum. Possible sources for this discrepancy are identified.

We report an improved measurement of $D^{+}\to K_S^0{K}^{+}$ and $D_s^{+}\to K_S^0{\pi }^{+}$ branching ratios using $605{\mathrm{fb}}^{-1}$ of data collected with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. The measured branching ratios with respect to the Cabibbo-favored modes are $\mathcal{B}(D^{+}\to K_S^0{K}^{+})/\mathcal{B}(D^{+}\to K_S^0{\pi }^{+})=0.1899\pm 0.0011\pm 0.0022$ and $\mathcal{B}(D_s^{+}\to K_S^0{\pi }^{+})/\mathcal{B}(D_s^{+}\to K_S^0{K}^{+})=0.0803\pm 0.0024\pm 0.0019$ where the first uncertainties are statistical and the second are systematic.

We consider zero-temperature transitions from conformal to nonconformal phases in quantum theories. We argue that there are three generic mechanisms for the loss of conformality in any number of dimensions: (i) fixed point goes to zero coupling, (ii) fixed point runs off to infinite coupling, or (iii) an IR fixed point annihilates with a UV fixed point and they both disappear into the complex plane. We give both relativistic and nonrelativistic examples of the last case in various dimensions and show that the critical behavior of the mass gap behaves similarly to the correlation length in the finite temperature Berezinskii-Kosterlitz-Thouless (BKT) phase transition in two dimensions, $\xi \sim \exp (c/|T-T_c{|}^{1/2})$. We speculate that the chiral phase transition in QCD at large number of fermion flavors belongs to this universality class, and attempt to identify the UV fixed point that annihilates with the Banks-Zaks fixed point at the lower end of the conformal window.

We propose a way towards a dynamical solution of the strong $CP$ in models with compact extra dimensions. To this aim we consider a one dimensional toy model for QCD, which contains a vacuum angle and a strong $CP$-like problem. We further consider a higher dimensional theory, which has a trivial vacuum structure and which reproduces the perturbative properties of the toy model in the low-energy limit. In the weak coupling regime, where our computations are valid, we show that the vacuum structure of the low-energy action is still trivial and the strong $CP$ problem does not arise. Also, no axionlike particles are generated in this setup.

We discuss the particle production due to a semitransparent mirror accelerating on the trajectories which simulate the Hawking effect. We find in accordance with a previous result [3] that the number of emitted particles up to infinite times remains finite, but in contrast to the cited paper, we obtain that for large, but finite reflectivities of the mirror, the radiated spectrum is Bose-Einstein and not Fermi-Dirac. We compare the beta coefficients $\beta ({\omega }^{\prime },\omega )$ for the perfectly reflecting and the semitransparency case and point out the differences in the sector of large frequencies ${\omega }^{\prime }$. For the perfect mirror, the source of the infinite number of particles are the frequencies ${\omega }^{\prime }\to \infty$, while for the semitransparent one this contribution is eliminated due to the cutoff effects introduced by the finite barrier energy of the mirror.

We discuss multiloop maximally helicity violating amplitudes in the $N=4$ supersymmetric Yang-Mills theory in terms of effective gravity in the momentum space with IR regulator branes as degrees of freedom. Kinematical invariants of external particles yield the moduli spaces of complex or Kahler structures which are the playgrounds for the Kodaira-Spencer or Kahler type gravity. We suggest fermionic representation of the loop maximally helicity violating amplitudes in the $N=4$ supersymmetric Yang-Mills theory assuming the identification of the IR regulator branes with Kodaira-Spencer fermions in the B model and Lagrangian branes in the A model. The two-easy mass box diagram is related to the correlator of fermionic currents on the spectral curve in the B model or hyperbolic volume in the A model and it plays the role of a building block in the whole picture. The Bern-Dixon-Smirnov–like ansatz has the interpretation as the semiclassical limit of a fermionic correlator. It is argued that fermionic representation implies a kind of integrability on the moduli spaces. We conjecture the interpretation of the reggeon degrees of freedom in terms of the open strings stretched between the IR regulator branes.

In this article, we quantize the Maxwell (“massless spin one”) de Sitter field in a conformally invariant gauge. This quantization is invariant under the ${\mathrm{SO}}_0(2,4)$ group and consequently under the de Sitter group. We obtain a new de Sitter-invariant two-point function which is very simple. Our method relies on the one hand on a geometrical point of view which uses the realization of Minkowski, de Sitter and anti-de Sitter spaces as intersections of the null cone in ${\mathbb{R}}^6$ and a moving plane, and on the other hand on a canonical quantization scheme of the Gupta-Bleuler type.

We introduce a cosmological model based on the normal branch of Dvali-Gabadadze-Porrati (DGP) braneworld gravity with a smooth dark energy component on the brane. The expansion history in this model is identical to $\Lambda \mathrm{CDM}$, thus evading all geometric constraints on the DGP crossover scale $r_c$. This well-defined model can serve as a first approximation to more general braneworld models whose cosmological solutions have not been obtained yet. We study the formation of large-scale structure in this model in the linear and nonlinear regime using N-body simulations for different values of $r_c$. The simulations use the code presented in [25] and solve the full nonlinear equation for the brane-bending mode in conjunction with the usual gravitational dynamics. The brane-bending mode is attractive rather than repulsive in the DGP normal branch, hence the sign of the modified gravity effects is reversed compared to those presented in [25]. We compare the simulation results with those of ordinary $\Lambda \mathrm{CDM}$ simulations run using the same code and initial conditions. We find that the matter power spectrum in this model shows a characteristic enhancement peaking at $k\sim 0.7h/\mathrm{Mpc}$. We also find that the abundance of massive halos is significantly enhanced. Other results presented here include the density profiles of dark matter halos, and signatures of the brane-bending mode self-interactions (Vainshtein mechanism) in the simulations. Independently of the expansion history, these results can be used to place constraints on the DGP model and future generalizations through their effects on the growth of cosmological structure.

We construct dark soliton solutions in a holographic model of a relativistic superfluid. We study the length scales associated with the condensate and the charge density depletion, and find that the two scales differ by a nontrivial function of the chemical potential. By adjusting the chemical potential, we study the variation of the depletion of charge density at the interface.

Exclusive $J/\Psi$ electroproduction is studied in the framework of the analytic $S$-matrix theory. The differential and integrated elastic cross sections are calculated using the modified dual amplitude with Mandelstam analyticity model. The model is applied to the description of the available experimental data and proves to be valid in a wide region of the kinematical variables $s$, $t$, and $Q^2$. Our amplitude can be used also as a universal background parametrization for the extraction of tiny resonance signals.

Neutralino dark matter can be indirectly detected by observing the gamma ray lines from the annihilation processes $\chi \chi \to \gamma \gamma$ and $\chi \chi \to \gamma Z$. In this paper we study the implications that the observation of these two lines could have for the determination of the supersymmetric parameter space. Within the minimal supergravity framework, we find that, independently of the dark matter distribution in the Galaxy, such observations by themselves would allow us to differentiate between the coannihilation region, the funnel region, and the focus point region. As a result, several restrictions on the minimal supergravity parameters can be derived. Within a more general minimal supersymmetric standard model scenario, we show that the observation of gamma ray lines might be used to discriminate between a bino-, a wino-, and a Higgsino-like neutralino, with important consequences for cosmology and for models of supersymmetry breaking. The detection of the $\gamma \gamma$ and $\gamma Z$ lines, therefore, will not only provide an unmistakable signature of dark matter, it will also open a new road toward the determination of supersymmetric parameters.