The warped bulk standard model has been studied in the Randall-Sundrum background on $S^1/{\mathbb{Z}}_2\times {\mathbb{Z}}_2^{\prime }$ interval with the bulk gauge symmetry $SU(3)\times SU(2{)}_L\times SU(2{)}_R\times U(1{)}_{B-L}$. With the assumption of no large cancellation between the fermion flavor mixing matrices, we present a simple analytic method to determine the bulk masses of standard model fermions in the almost universal bulk Yukawa coupling model. We also predict $U_{e3}$ element of MNS matrix to be near the experimental upper bound when the neutrino masses are of Dirac type.

A new derivation of the five-dimensional Myers-Perry black-hole metric as a 2-soliton solution on a nonflat background is presented. It is intended to be an illustration of how the well-known Belinski-Zakharov method can be applied to find solutions of the Einstein equations in $D$-dimensional space-time with $D-2$ commuting Killing vectors using the complete integrability of this system. The method appears also to be promising for the analysis of the uniqueness questions for higher-dimensional black holes.

A general analysis of $Q$-ball solutions of the supersymmetric $F$-term hybrid inflation field equations is given. The solutions consist of a complex inflaton field and a real symmetry-breaking field, with a conserved global charge associated with the inflaton. It is shown that the $Q$-ball solutions for any value of the superpotential coupling, $\kappa$, may be obtained from those with $\kappa =1$ by rescaling the space coordinates. The complete range of $Q$-ball solutions for the case $\kappa =1$ is given, from which all possible $F$-term inflation $Q$-balls can be obtained. The possible role of $F$-term inflation $Q$-balls in cosmology is discussed.

Recent results on the nonunitary character of quantum time evolution in the family of Gowdy $T^3$ spacetimes bring the question of whether one should abandon the most sacred principle of unitary evolution in cosmology. In this work we show that the answer is in the negative. We put forward a full nonperturbative canonical quantization of the polarized Gowdy $T^3$ model that implements the dynamics while preserving unitarity. We discuss possible implications of this result.

We present an analysis of charm quark fragmentation at 10.6 GeV, based on a data sample of $103{\mathrm{fb}}^{-1}$ collected by the Belle detector at the KEKB accelerator. We consider fragmentation into the main charmed hadron ground states, namely $D^0,D^{+},D_s^{+}$ and ${\Lambda }_c^{+}$, as well as the excited states $D^{*0}$ and $D^{*+}$. The fragmentation functions are important to measure as they describe processes at a low energy scale, where calculations in perturbation theory lead to large uncertainties. Fragmentation functions can also be used as input distributions for Monte Carlo generators. Additionally, we determine the average number of these charmed hadrons produced per $B$ decay at the ${\rm Y}(4S)$ resonance and measure the distribution of their production angle in $e^{+}{e}^{-}$ annihilation events and in $B$ decays.

The Lorentz decomposition of the light-cone distribution amplitudes is carried out up to twist four. The Wandzura-Wilczek-like relations associated with the transverse photon wave function are derived in the same way as for the rho meson. The on-shell and off-shell photon wave functions with odd chirality at the leading twist in the effective low-energy theory derived from the instanton vacuum of QCD are calculated. The explicit expression of the transverse photon wave function, ${\varphi }_{\gamma \perp }(u,P^2)$, is worked out, and the twist-two parts of the other two photon wave functions, $h_{\gamma \parallel }^{(s),\mathrm{twist}\mathrm{two}}(u,P^2)$ and $h_{\gamma \parallel }^{(t),\mathrm{twist}\mathrm{two}}(u,P^2)$, are calculated based on the Wandzura-Wilczek-like relations. The dependence of the coupling $f_{\gamma }^{\perp }(P^2)$ and the light-cone photon wave functions with respect to the virtuality, $P^2$, are analyzed, and the end-point behavior as well as the middle-point behavior of the photon wave functions is discussed.

There exists a class of gauge models incorporating a finite density of matter in which the Higgs mechanism is provided by condensates of gauge (or gauge plus scalar) fields, i.e., there are vector condensates in this case. We describe vortex solutions in the simplest model in this class, the gauged $\mathrm{SU}(2)\times \mathrm{U}(1{)}_Y$ $\sigma$ model with the chemical potential for hypercharge $Y$, in which the gauge symmetry is completely broken. It is shown that there are three types of topologically stable vortices in the model, connected either with photon field or hypercharge gauge field, or with both of them. Explicit vortex solutions are numerically found and their energy per unit length are calculated. The relevance of these solutions for the gluonic phase in the dense two-flavor QCD is discussed.

We consider the couplings of an infinite number of spin-2 fields to gravity appearing in Kaluza-Klein theories. They are constructed as the broken phase of a massless theory possessing an infinite-dimensional spin-2 symmetry. Focusing on a circle compactification of four-dimensional gravity we show that the resulting gravity/spin-2 system in $D=3$ has in its unbroken phase an interpretation as a Chern-Simons theory of the Kac-Moody algebra $\widehat{iso(1,2)}$ associated to the Poincaré group and also fits into the geometrical framework of algebra-valued differential geometry developed by Wald. Assigning all degrees of freedom to scalar fields, the matter couplings in the unbroken phase are determined, and it is shown that their global symmetry algebra contains the Virasoro algebra together with an enhancement of the Ehlers group $SL(2,\mathbb{R})$ to its affine extension. The broken phase is then constructed by gauging a subgroup of the global symmetries. It is shown that metric, spin-2 fields and Kaluza-Klein vectors combine into a Chern-Simons theory for an extended algebra, in which the affine Poincaré subalgebra acquires a central extension.

We present here a detailed study of the quasinormal spectrum of brane-localized standard model fields in the vicinity of $D$-dimensional black holes. A variety of such backgrounds [Schwarzschild, Reissner-Nordström and Schwarzszchild-(anti–)de Sitter] are investigated. The dependence of the quasinormal spectra on the dimensionality $D$, spin of the field $s$, and multipole number $\ell$ is analyzed. Analytical formulas are obtained for a number of limiting cases: in the limit of large multipole number for Schwarzschild, Schwarzschild-de Sitter, and Reissner-Nordström black holes, in the extremal limit of the Schwarzschild-de Sitter black hole, and in the limit of small horizon radius in the case of Schwarzschild-anti–de Sitter black holes. We show that an increase in the number of hidden, extra dimensions results in the faster damping of all fields living on the brane, and that the localization of fields on a brane affects the quasinormal spectrum in a number of additional ways, both direct and indirect.

The fluorescence technique has been successfully used to detect ultrahigh energy cosmic rays by indirect measurements. The underlying idea is that the number of charged particles in the atmospheric shower, i.e, its longitudinal profile, can be extracted from the amount of emitted nitrogen fluorescence light. However the influence of shower fluctuations and the very possible presence of different nuclear species in the primary cosmic ray spectrum makes the estimate of the shower energy from the fluorescence data analysis a difficult task. We investigate the potential of shower size at maximum depth as estimator of shower energy. The detection of the fluorescence light is simulated in detail and the reconstruction biases are carefully analyzed. We extend our calculations to both HiRes and EUSO experiments. This approach has shown some advantages to the reconstruction of the energy when compared to the standard analysis procedure.

We perform numerical simulations of cosmic string evolution with intercommuting probability $P$ in the range $5\times {10}^{-3}\le P\le 1$, both in the matter and radiation eras. We find that the dependence of the scaling density on $P$ is significantly different than the suggested $\rho \propto P^{-1}$ form. In particular, for probabilities greater than $P\simeq 0.1$, $\rho (1/P)$ is approximately flat, but for $P$ less than this value it is well-fitted by a power-law with exponent ${0.6}_{-0.12}^{+0.15}$. This shows that the enhancement of string densities due to a small intercommuting probability is much less prominent than initially anticipated. We interpret the flat part of $\rho (1/P)$ in terms of multiple opportunities for string reconnections during one crossing time, due to small-scale wiggles. We also propose a two-scale model, which satisfactorily fits our results over the whole range of $P$ covered by the simulations.

We examine, in a model independent way, the sensitivity of a linear collider to the couplings of a light Higgs boson to gauge bosons. Including the possibility of $CP$ violation, we construct several observables that probe the different anomalous couplings possible. For an intermediate mass Higgs, a collider operating at a center-of-mass energy of 500 GeV and with an integrated luminosity of $500{\mathrm{fb}}^{-1}$ is shown to be able to constrain the $ZZH$ vertex at the few per cent level, and with even higher sensitivity in certain directions. However, the lack of sufficient number of observables as well as contamination from the $ZZH$ vertex limits the precision with which the $WWH$ coupling can be measured.

We perform a nonperturbative determination of the $O(a)$-improvement coefficient $c_{\mathrm{SW}}$ and the critical hopping parameter ${\kappa }_c$ for $N_f=3$, 2, and 0 flavor QCD with the (RG) renormalization-group-improved gauge action using the Schrödinger functional method. In order to interpolate $c_{\mathrm{SW}}$ and ${\kappa }_c$ as a function of the bare coupling, a wide range of $\beta$ from the weak coupling region to the moderately strong coupling points used in large-scale simulations is studied. Corrections at finite lattice size of $O(a/L)$ turned out to be large for the RG-improved gauge action, and hence we make the determination at a size fixed in physical units using a modified improvement condition. This enables us to avoid $O(a)$ scaling violations which would remain in physical observables if $c_{\mathrm{SW}}$ determined for a fixed lattice size $L/a$ is used in numerical simulations.

We present a theoretical framework that accounts for the new $D_J$ and $D_{sJ}$ mesons measured in the open-charm sector. These resonances are properly described if considered as a mixture of conventional $P$-wave quark-antiquark states and four-quark components. The narrowest states are basically $P$-wave quark-antiquark mesons, while the dominantly four-quark states are shifted above the corresponding two-meson threshold, being broad resonances. We study the electromagnetic decay widths as basic tools to scrutiny their nature. The proposed explanation incorporates in a natural way the most recently discovered mesons in charmonium spectroscopy.

Using data obtained with the CLEO III detector, running at the Cornell Electron Storage Ring (CESR), we report on a new study of exclusive radiative ${\rm Y}(1\mathrm{S})$ decays into the final states $\gamma {\pi }^{+}{\pi }^{-}$, $\gamma K^{+}{K}^{-}$, and $\gamma p\overline{p}$. We present branching ratio measurements for the decay modes ${\rm Y}(1\mathrm{S})\to \gamma f_2(1270)$, ${\rm Y}(1\mathrm{S})\to \gamma f_2^{\prime }(1525)$, and ${\rm Y}(1\mathrm{S})\to \gamma K^{+}{K}^{-}$; helicity production ratios for $f_2(1270)$ and $f_2^{\prime }(1525)$; upper limits for the decay ${\rm Y}(1\mathrm{S})\to \gamma f_J(2200)$, with $f_J(2220)\to {\pi }^{+}{\pi }^{-}$, $K^{+}{K}^{-}$, $p\overline{p}$; and an upper limit for the decay ${\rm Y}(1\mathrm{S})\to \gamma X(1860)$, with $X(1860)\to \gamma p\overline{p}$.

The iterated Crank-Nicolson is a predictor-corrector algorithm commonly used in numerical relativity for the solution of both hyperbolic and parabolic partial differential equations. We here extend the recent work on the stability of this scheme for hyperbolic equations by investigating the properties when the average between the predicted and corrected values is made with unequal weights and when the scheme is applied to a parabolic equation. We also propose a variant of the scheme in which the coefficients in the averages are swapped between two corrections leading to systematically larger amplification factors and to a smaller numerical dispersion.

Braneworld scenarios are motivated by string/M-theory and can be characterized by the way in which they modify the conventional Friedmann equations of Einstein gravity. An alternative approach to quantum gravity, however, is the loop quantum cosmology program. In the semiclassical limit, the cosmic dynamics in this scenario can also be described by a set of modified Friedmann equations. We demonstrate that a dynamical correspondence can be established between these two paradigms at the level of the effective field equations. This allows qualitatively similar features between the two approaches to be compared and contrasted as well as providing a framework for viewing braneworld scenarios in terms of constrained Hamiltonian systems. As concrete examples of this correspondence, we illustrate the relationships between different cosmological backgrounds representing scaling solutions.

We examine the behavior of dark energy models in the plane defined by $w$ (the equation of state parameter for the dark energy) and $w^{\prime }$ (the derivative of $w$ with respect to the logarithm of the scale factor). For nonphantom barotropic fluids with positive squared sound speed, we find that $w^{\prime }<3w(w+1)$, the opposite of the bound on quintessence models previously derived by Caldwell and Linder. Thus, these barotropic models and quintessence models for the dark energy occupy disjoint regions in the $w-w^{\prime }$ plane. We also derive two new bounds for quintessence models in the $w-w^{\prime }$ plane: the first is a general bound for any scalar field with a monotonic potential, while the second improves on the Caldwell-Linder bound for tracker quintessence models. Observationally distinguishing barotropic models from quintessence models requires $\sigma (w^{\prime })\lesssim 1+w$.