We derive new rotating nonasymptotically flat black ring solutions in five-dimensional Einstein-Maxwell-dilaton gravity with the dilaton coupling constant $\alpha =\sqrt{8/3}$, which arises from a six-dimensional Kaluza-Klein theory. As a limiting case we also find new rotating nonasymptotically flat five-dimensional black holes. The solutions are analyzed and the mass, angular momentum, and charge are computed. A Smarr-like relation is found. It is shown that the first law of black hole thermodynamics is satisfied.

We construct and investigate a compactified version of the four-dimensional Reissner-Nordström-Taub-NUT solution, generalizing the compactified Schwarzschild black hole that has been previously studied by several workers. Our approach to compactification is based on dimensional reduction with respect to the stationary Killing vector, resulting in three-dimensional gravity coupled to a nonlinear sigma model. Knowing that the original noncompactified solution corresponds to a target space geodesic, the problem can be linearized much in the same way as in the case of no electric or Taub-NUT charge. An interesting feature of the solution family is that, for nonzero electric charge but vanishing Taub-NUT charge, the solution has a curvature singularity on a torus that surrounds the event horizon, but this singularity is removed when the Taub-NUT charge is switched on. We also treat the Schwarzschild case in a more complete way than has been done previously. In particular, the asymptotic solution (the Levi-Cività solution with the height coordinate made periodic) has to our knowledge only been calculated up to a determination of the mass parameter. The periodic Levi-Cività solution contains three essential parameters, however, and the remaining two are explicitly calculated here.

Experimental projects using spherical antennas to detect gravitational waves are nowadays a concrete reality. The main purpose of this paper is to give a possible way of interpreting output data from such a system. Responses of the five fundamental quadrupole modes and of the six resonators in truncated icosahedral gravitational wave antenna (TIGA) collocations are shown as a function of the incoming direction of the incident wave. Then, for a source lying in the galactic plane, sidereal time and galactic longitude dependence is given. Thus, once a candidate source of gravitational waves is considered, we can exactly predict the resonators’ response as a function of time.

We study classical dynamics in the spherical ansatz for the $SU(2)$ gauge and Higgs fields of the electroweak standard model in the absence of fermions and the photon. With the Higgs boson mass equal to twice the gauge boson mass, we numerically demonstrate the existence of oscillons, extremely long-lived localized configurations that undergo regular oscillations in time. We have only seen oscillons in this reduced theory when the masses are in a two-to-one ratio. If a similar phenomenon were to persist in the full theory, it would suggest a preferred value for the Higgs mass.

The character change of a superfluid state due to the variation of the attractive force is investigated in the relativistic framework with a massive fermion. Two crossovers are found. One is a crossover from the usual BCS state to the Bose-Einstein condensation (BEC) of bound fermion pairs. The other is from the BEC to the relativistic Bose-Einstein condensation (RBEC) of nearly massless bound pairs where antiparticles as well as particles dominate the thermodynamics. Possible realization of the BEC and RBEC states in the quark matter is also pointed out.

We study the renormalization group evolution of the Higgs quartic coupling ${\lambda }_H$. The one loop equation for ${\lambda }_H$ is nonlinear and it is of the Riccati type which we analytically and numerically solve in the energy range $[m_t,E_{GU}]$ where $m_t$ is the mass of the top quark and $E_{GU}={10}^{14}\mathrm{GeV}$. We find that depending on the value of ${\lambda }_H(m_t)$ the solution for ${\lambda }_H(E)$ may have a singularity or a zero and become negative in the former energy range so the ultraviolet cutoff of the standard model should be below or equal to the energy where the zero or singularity of ${\lambda }_H$ occurs. We then numerically solve the two loop renormalization group equation for ${\lambda }_H$ and compare it with the one loop solution. We find that the two loop running of ${\lambda }_H$ is very sensitive to the evolution of the top quark Yukawa coupling $Y_t$. This implies a strong dependence on the top quark mass $m_t$ and suggests that the choice of $m_t$ as the renormalization point, that we use, reduces theoretical errors. We find that in the approximation of one loop for $0.397\le {\lambda }_H(m_t)\le 0.618$ the standard model is valid in the whole range $[m_t,E_{GU}]$ while for two loops the bound is $0.368\le {\lambda }_H(m_t)\le 0.621$. From the properties of ${\lambda }_H$ we then study the predictions for the Higgs mass. We use the effective potential to derive the relation between the Higgs mass and ${\lambda }_H$ and obtain that this relation is not very sensitive to the particular choice of the effective potential but for the large Higgs masses the two loop corrections are significant. We determine that the standard model is valid in the whole range $[m_t,E_{GU}]$ for the Higgs masses $153.5\le M_H\le 191.1$ for one loop case and $148.5\le M_H\le 193.1$ for two loops. The pattern of the behavior of ${\lambda }_H(E)$ for different values of ${\lambda }_H(m_t)$ indicates the existence of a phase transition in the standard model for ${\lambda }_H(m_t)=0.5$ which corresponds to the value of the Higgs mass $M_H=m_t$.

We study previously unconsidered 3-3-1 models which are characterized by each lepton generation having a different representation under the gauge group. Flavor-changing neutral currents in the lepton sector occur in these models. To satisfy constraints on $\mu \to 3e$ decays, the $Z^{\prime }$ must be heavier than 2 to 40 TeV, depending on the model and assignments of the leptons. These models can result in very unusual Higgs decay modes. In most cases the $\mu \tau$ decay state is large (in one case, it is the dominant mode), and in one case, the $\Phi \to s\overline{s}$ rate dominates.

We discuss ideal delocalization of fermions in a bulk $SU(2)\times SU(2)\times U(1)$ Higgsless model with a flat or warped extra dimension. So as to make an extra dimensional interpretation possible, both the weak and hypercharge properties of the fermions are delocalized, with the $U(1{)}_Y$ current of left-handed fermions being correlated with the $SU(2{)}_W$ current. We find that (to subleading order) ideal fermion delocalization yields vanishing precision electroweak corrections in this continuum model, as found in corresponding theory-space models based on deconstruction. In addition to explicit calculations, we present an intuitive argument for our results based on Georgi’s spring analogy. We also discuss the conditions under which the essential features of an $SU(2)\times SU(2)\times U(1)$ bulk gauge theory can be captured by a simpler $SU(2)\times SU(2)$ model.

The branching ratio for $B\to K_1\gamma$ at next-to-leading order of ${\alpha }_s$ has been calculated in large energy effective theory. By incorporating higher twist effects in the light-cone decay amplitude for the axial $K$ meson, it is shown that the form factor is not sensitive to these twists.

We confirm the results of previous works that the internal motion of quarks inside charmonium mesons increases the cross section of the process $e^{+}{e}^{-}\to J/\psi {\eta }_c$. We also show, that this effect increases the widths of the scalar meson decay into two vector ones and state that the decays ${\chi }_{b0,2}\to 2J/\psi$ can be used to detect these scalar mesons at Tevatron and LHC colliders.

The factorization properties of the radiative decays $B\to V\gamma$ are analyzed at leading order in $1/m_b$ using the soft-collinear effective theory. It is shown that the decay amplitudes can be expressed in terms of a $B\to V$ form factor evaluated at $q^2=0$, light-cone distribution amplitudes of the $B$ and $V$ mesons, and calculable hard-scattering kernels. The renormalization-group equations in the effective theory are solved to resum perturbative logarithms of the different scales in the decay process. Phenomenological implications for the $B\to K^{*}\gamma$ branching ratio, isospin asymmetry, and $CP$ asymmetries are discussed, with particular emphasis on possible effects from physics beyond the standard model.

We discuss the possibility of the existence of tetraquark states made of four quarks in the string (flux tube) model. The new particle is composed of a diquark and an antidiquark which are connected by a color flux. It is shown that the vibrational and rotational excited states of the string explain some non-$\overline{q}q$ mesons observed experimentally. Moreover we discuss the decay widths of such tetraquarks with the use of the Schwinger mechanism.

We study the decay process of the $Z$ boson to a photon and a graviton. The most general form of the on-shell amplitude, subject to the constraints due to the conservation of the electromagnetic current and the energy-momentum tensor, is determined. The amplitude is expressed in terms of three form factors, two of which are $CP$ odd while one is $CP$ even. The latter, which is the only nonzero form factor at the one-loop level, is computed in the standard model and the decay rate is determined.

We perform a search for the exclusive radiative decay $B^0\to \varphi \gamma$, which is dominated by $\overline{b}d$ annihilation, in a sample of $124\times {10}^6$ $B\overline{B}$ events collected with the BABAR detector at the PEP-II asymmetric-energy $e^{+}{e}^{-}$ storage ring at SLAC. No significant signal is seen. We set an upper limit on the branching fraction of $\mathcal{B}(B^0\to \varphi \gamma )<8.5\times {10}^{-7}$ at the 90% confidence level.

In this work we calculate the functional generator of the Green’s functions of the Kalb-Ramond field in $3+1$ dimensions. We also calculate the functional generator, and corresponding Casimir energy, of the same field when it is submitted to boundary conditions on two parallel planes. The boundary conditions we consider can be interpreted as a kind of conducting plane for the field in comparing with the Maxwell case. We compare our result with the standard ones for the scalar and Maxwell fields.

Particle production by slow-changing gravitational fields is usually described using quantum field theory in curved spacetime. Calculations require a definition of the vacuum state, which can be given using the adiabatic (WKB) approximation. I investigate the best attainable precision of the resulting approximate definition of the particle number. The standard WKB ansatz yields a divergent asymptotic series in the adiabatic parameter. I derive a novel formula for the optimal number of terms in that series and demonstrate that the error of the optimally truncated WKB series is exponentially small. This precision is still insufficient to describe particle production from vacuum, which is typically also exponentially small. An adequately precise approximation can be found by improving the WKB ansatz through perturbation theory. I show quantitatively that the fundamentally unavoidable imprecision in the definition of particle number in a time-dependent background is equal to the particle production expected to occur during that epoch. The results are illustrated by analytic and numerical examples.

Full interpretation of data from gravitational wave observations will require accurate numerical simulations of source systems, particularly binary black hole mergers. A leading approach to improving accuracy in numerical relativity simulations of black hole systems is through fixed or adaptive mesh refinement techniques. We describe a manifestation of numerical interface truncation error which appears as significant, artificial reflections from refinement boundaries in a broad class of mesh refinement implementations, potentially compromising the effectiveness of mesh refinement techniques for some numerical relativity applications (if left untreated). We elucidate this numerical effect by presenting a model problem which exhibits the phenomenon, but which is simple enough that its numerical error can be understood analytically. Our analysis shows that the effect is caused by variations in finite differencing error generated across low and high resolution regions, and that associated difficulties in demonstrating convergence at modest resolutions are caused by the presence of dramatic speed differences among propagation modes typical of $3+1$ relativity. Last, to further verify our understanding of this problem, we present a class of finite differencing stencils of the same order of accuracy as the desired order of convergence, termed mesh-adapted differencing (MAD), which eliminate this pathology in both our model problem and in numerical relativity examples.

We compute the secondary cosmic microwave background radiation (CMBR) anisotropy signal from the reionization of the Universe in the presence of tangled magnetic fields. We consider the tangled-magnetic-field-induced scalar, vector, and tensor modes for our analysis. The most interesting signal for $\ell \lesssim 100$ arises from tensor perturbations. In particular, we show that the enhancement observed by Wilkinson microwave anisotropy probe (WMAP) in the TE cross-correlation signal for $\ell \lesssim 10$ could be explained by tensor TE cross correlation from tangled magnetic fields generated during the inflationary epoch for magnetic field strength $B_0\simeq 4.5\times {10}^{-9}\mathrm{G}$ and magnetic field power spectrum spectral index $n\simeq -2.9$. Alternatively, a mixture of tensor mode signal with primordial scalar modes gives weaker bounds on the value of the optical depth to the reionization surface, ${\tau }_{\mathrm{reion}}$: ${\tau }_{\mathrm{reion}}=0.11\pm 0.02$. This analysis can also be translated to a limit on magnetic field strength of $\simeq 5\times {10}^{-9}\mathrm{G}$ for wave numbers $\lesssim 0.05\mathrm{Mp}{\mathrm{c}}^{-1}$.

$\gamma \gamma \to {\Pi }_t^0$ is the major production mechanism of the neutral top pion at the linear colliders. In this paper, we calculate the cross section of the process $\gamma \gamma \to {\Pi }_t^0$ and discuss the potential to observe the neutral top pion via its various decay modes at the planned International Linear Collider. The study shows that, among the various neutral top-pion production processes at the linear colliders, the cross section of $\gamma \gamma \to {\Pi }_t^0$ is the largest one which can reach the level of ${10}^1-{10}^2\mathrm{fb}$. Because of the existence of the tree-level flavor-changing coupling ${\Pi }_t^{0}t\overline{c}$, $\gamma \gamma \to {\Pi }_t^0\to t\overline{c}$ can provide enough number of typical signals to identify the neutral top pion with the clean SM background. Therefore, the process $\gamma \gamma \to {\Pi }_t^0$ plays an important role in searching for the neutral top pion and tests the TC2 model.