We measure the time-dependent $CP$ asymmetry parameters in $B^0\to K^{+}{K}^{-}{K}^0$ based on a data sample of approximately $227\times {10}^6$ $B$-meson pairs recorded at the ${\rm Y}(4S)$ resonance with the BABAR detector at the PEP-II $B$-meson Factory at SLAC. We reconstruct two-body $B^0$ decays to $\varphi (1020)K_S^0$ and $\varphi (1020)K_L^0$, and the three-body decay $K^{+}{K}^{-}{K}_S^0$ with $\varphi (1020)K_S^0$ excluded. For the $B^0\to \varphi K^0$ decays, we measure $\sin 2{\beta }_{\mathrm{eff}}(\varphi K^0)=+0.50\pm 0.25(\mathrm{stat}{)}_{-0.04}^{+0.07}(\mathrm{syst})$. The $B^0\to K^{+}{K}^{-}{K}_S^0$ decays are dominated by $K^{+}{K}^{-}$ $S$ wave, as determined from an angular analysis; we measure $\sin 2{\beta }_{\mathrm{eff}}(K^{+}{K}^{-}{K}_S^0)=+0.55\pm 0.22(\mathrm{stat})\pm 0.04(\mathrm{syst})\pm 0.11(CP)$, where the last error is due to the uncertainty in the fraction of $CP$-even contributions to the decay amplitude. We find no evidence for direct $CP$ violation.

We study the evolution of relic D3-branes after the $\mathrm{D}3/\overline{\mathrm{D}3}$-brane inflation in string warped compactification. The motion of D3-branes can be frozen under certain conditions during the radiation/matter domination. These D3-branes cannot be released until the $\mathrm{D}3/\overline{\mathrm{D}3}$-branes potential energy becomes dominated at late time. Subsequently, they will move towards to $\overline{\mathrm{D}3}$-branes, which play the role of uplifting AdS minimum to dS minimum, near the apex of throats. The annihilation of $\mathrm{D}3/\overline{\mathrm{D}3}$-branes leads to the disappearance of dS vacua. This process may be regarded as a rapid decay channel of present dS vacua. We discuss the parameter spaces required by this process and calculate the decay time.

We consider the complex, massive Klein-Gordon field living in the noncommutative space, and coupled to noncommutative electromagnetic fields. After employing the Seiberg-Witten map to first order, we analyze the noncommutative Klein-Gordon theory as $c$, which corresponds to the velocity of light, goes to infinity. We show that the theory exhibits a regular “magnetic” limit only for certain forms of magnetic fields. The resulting theory is nothing but the Schrödinger theory in a gravitational background generated by the gauge fields.

The vacuum expectation value of the stress-energy tensor is calculated for spin $\frac{1}{2}$ massive fields in several multiply connected flat space-times. We examine the physical effects of topology on manifolds such as $R^3\times S^1$, $R^2\times T^2$, $R^1\times T^3$, the Möbius strip, and the Klein bottle. We find that the spinor vacuum stress tensor has the opposite sign to, and twice the magnitude of, the scalar tensor in orientable manifolds. Extending the above considerations to the case of Misner spacetime, we calculate the vacuum expectation value of spinor stress-energy tensor in this space and discuss its implications for the chronology protection conjecture.

We aim at the construction of dark energy models without exotic matter but with a phantomlike equation of state (an effective phantom phase). The first model we consider is decaying vacuum cosmology where the fluctuations of the vacuum are taken into account. In this case, the phantom cosmology (with an effective, observational $\omega$ being less than $-1$ ) emerges even for the case of a real dark energy with a physical equation of state parameter $\omega$ larger than $-1$. The second proposal is a generalized holographic model, which is produced by the presence of an infrared cutoff. It also leads to an effective phantom phase, which is not a transient one as in the first model. However, we show that quantum effects are able to prevent its evolution towards a big rip singularity.

The transport equations for polarized radiation transfer in non-Riemannian, Weyl-Cartan type space-times are derived, with the effects of both torsion and nonmetricity included. To obtain the basic propagation equations we use the tangent bundle approach. The equations describing the time evolution of the Stokes parameters, of the photon distribution function and of the total polarization degree can be formulated as a system of coupled first-order partial differential equations. As an application of our results we consider the propagation of the cosmological gamma-ray bursts in spatially homogeneous and isotropic spaces with torsion and nonmetricity. For this case the exact general solution of the equation for the polarization degree is obtained, with the effects of the torsion and nonmetricity included. The presence of a non-Riemannian geometrical background in which the electromagnetic fields couple to torsion and/or nonmetricity affect the polarization of photon beams. Consequently, we suggest that the observed polarization of prompt cosmological gamma-ray bursts and of their optical afterglows may have a propagation effect component, due to a torsion/nonmetricity induced birefringence of the vacuum. A cosmological redshift and frequency dependence of the polarization degree of gamma-ray bursts also follows from the model, thus providing a clear observational signature of the torsional/nonmetric effects. On the other hand, observations of the polarization of the gamma-ray bursts can impose strong constraints on the torsion and nonmetricity and discriminate between different theoretical models.

We perform an analysis of the $K^{*}$ polarization states in the exclusive $B$ meson decay $B^0\to K^{*0}(\to K^{-}{\pi }^{+})l^{+}{l}^{-}$ ($l=e,\mu ,\tau$) in the low dilepton mass region, where the final vector meson has a large energy. Working in the transversity basis, we study various observables that involve the $K^{*}$ spin amplitudes $A_{\perp }$, $A_{\parallel }$, $A_0$ by exploiting the heavy-to-light form-factor relations in the heavy quark and large-$E_{K^{*}}$ limit. We find that at leading order in $1/m_b$ and ${\alpha }_s$ the form-factor dependence of the asymmetries that involve transversely polarized $K^{*}$ completely drops out. At next-to-leading logarithmic order, including factorizable and nonfactorizable corrections, the theoretical errors for the transverse asymmetries turn out to be small in the standard model (SM). Integrating over the lower part of the dimuon mass region, and varying the theoretical input parameters, the SM predicts ${\mathcal{A}}_T^{(1)}=0.9986\pm 0.0002$ and ${\mathcal{A}}_T^{(2)}=-0.043\pm 0.003$. In addition, the longitudinal and transverse polarization fractions are found to be $(69\pm 3)\%$ and $(31\pm 3)\%$, respectively, so that ${\Gamma }_L/{\Gamma }_T=2.23\pm 0.31$. Beyond the SM, we focus on new physics that mainly gives sizable contributions to the coefficients $C_7^{\mathrm{eff}(\prime )}$ of the electromagnetic dipole operators. Taking into account experimental data on rare $B$ decays, we find large effects of new physics in the transverse asymmetries. Furthermore, we show that a measurement of longitudinal and transverse polarization fractions will provide complementary information on physics beyond the SM.

Using photon conversions to $e^{+}{e}^{-}$ pairs, the energy spectrum of inclusive photons from $\psi (2S)$ radiative decays is measured with photon energy resolution (${\sigma }_{E_{\gamma }}$) in the range from 2.3 to 3.8 MeV by BESII at the Beijing Electron-Positron Collider. The ${\chi }_{cJ}(1P)$ states ($J=0,1,2$) are clearly observed, and their masses and the spin-averaged ${\chi }_{cJ}$ mass are determined to be $M_{{\chi }_{c0}}=3414.21\pm 0.39\pm 0.27$, $M_{{\chi }_{c1}}=3510.30\pm 0.14\pm 0.16$, $M_{{\chi }_{c2}}=3555.70\pm 0.59\pm 0.39$, and $M({}^{3}P_{\mathrm{cog}})=3524.85\pm 0.32\pm 0.30\mathrm{MeV}/c^2$, respectively.

Effective stochastic equations for the continuous transitions of relativistic quantum fields inevitably contain multiplicative noise. We examine the effect of such noise in a numerical simulation of a temperature quench in a $1+1$ dimensional scalar theory. We look at out-of-equilibrium defect formation and compare our results with those of stochastic equations with purely additive noise.

We consider $2+1$ dimensional noncommutative models of scalar and fermionic fields coupled to the Chern-Simons field. We show that, at least up to one loop, the model containing only a fermionic field in the fundamental representation minimally coupled to the Chern-Simons field is consistent in the sense that there are no nonintegrable infrared divergences. By contrast, dangerous infrared divergences occur if the fermion field belongs to the adjoint representation or if the coupling of scalar matter is considered instead. The superfield formulation of the supersymmetric Chern-Simons model is also analyzed and shown to be free of nonintegrable infrared singularities and actually finite if the matter field belongs to the fundamental representation of the supergauge group. In the case of the adjoint representation this happens only in a particular gauge.

Einstein’s theory of general relativity is written in terms of the variables obtained from a conformal-traceless decomposition of the spatial metric and extrinsic curvature. The determinant of the conformal metric is not restricted, so the action functional and equations of motion are invariant under conformal transformations. With this approach the conformal-traceless variables remain free of density weights. The conformal invariance of the equations of motion can be broken by imposing an evolution equation for the determinant of the conformal metric $g$. Two conditions are considered, one in which $g$ is constant in time and one in which $g$ is constant along the unit normal to the spacelike hypersurfaces. This approach is used to write the Baumgarte-Shapiro-Shibata-Nakamura system of evolution equations in conformally invariant form. The presentation includes a discussion of the conformal thin sandwich construction of gravitational initial data, and the conformal flatness condition as an approximation to the evolution equations.

The evolution of primordial black holes in a flat Friedmann universe with a massless scalar field is investigated in fully general relativistic numerical relativity. A primordial black hole is expected to form with a scale comparable to the cosmological apparent horizon, in which case it may go through an initial phase with significant accretion. However, if it is very close to the cosmological apparent horizon size, the accretion is suppressed due to general relativistic effects. In any case, it soon gets smaller than the cosmological horizon and thereafter it can be approximated as an isolated vacuum solution with decaying mass accretion. In this situation the dynamical and inhomogeneous scalar field is typically equivalent to a perfect fluid with a stiff equation of state $p=\rho$. The black hole mass never increases by more than a factor of 2, despite recent claims that primordial black holes might grow substantially through accreting quintessence. It is found that the gravitational memory scenario, proposed for primordial black holes in Brans-Dicke and scalar-tensor theories of gravity, is highly unphysical.

We provide precise constraints on the size of any black holes forming in the early Universe for a variety of formation scenarios. In particular, we prove that the size of the apparent horizon of a primordial black hole formed by causal processes in a flat Friedmann universe is considerably smaller than the cosmological apparent horizon size for an equation of state $p=k\rho$ ($1/3<k<1$). This also applies for a stiff equation of state ($k=1$) or for a massless scalar field. The apparent horizon of a primordial black hole formed through hydrodynamical processes is also considerably smaller than the cosmological apparent horizon for $0<k\le 1$. We derive an expression for the maximum size which an overdense region can have without being a separate closed universe rather than part of our own. Newtonian argument shows that a black hole smaller than the cosmological horizon can never accrete much.

This paper is a supplement of our earlier work [H.-Z. Chen, Y. Tian, Y.-H. Gao, and X.-C. Song, J. High Energy Phys. 10 (2004) 011.]. We map the vector potential of charged black holes into GEMS and find that its effect on the thermal spectrum is the same as that on the black hole side, i.e., it will induce a chemical potential in the thermal spectrum which is the same as that in the charged black holes. We also argue that the generalization of GEMS approach to nonstationary motions is not possible.

This paper discusses traversable wormholes that differ slightly but significantly from those of the Morris-Thorne type under the assumption of cylindrical symmetry. The throat is a piecewise smooth cylindrical surface resulting in a shape function that is not differentiable at some value. It is proposed that the regular derivative be replaced by a one-sided derivative at this value. The resulting wormhole geometry satisfies the weak energy condition.

We study the Blackwell-Rao (BR) estimator of the probability distribution of the angular power spectrum, $P(C_{\ell }\mid \mathbf{d})$, by applying it to samples of full-sky no-noise CMB maps generated via Gibbs sampling. We find the estimator, given a set of samples, to be very fast and also highly accurate, as determined by tests with simulated data. We also find that the number of samples required for convergence of the BR estimate rises rapidly with increasing $\ell$, at least at low $\ell$. Our existing sample chains are only long enough to achieve convergence at $\ell \lesssim 40$. In comparison with $P(C_{\ell }\mid \mathbf{d})$ as reported by the WMAP team we find significant differences at these low $\ell$ values. These differences lead to up to $\sim 0.5\sigma$ shifts in the estimates of parameters in a 7-parameter $\Lambda \mathrm{CDM}$ model with nonzero $d{n}_s/d\ln k$. Fixing $d{n}_s/d\ln k=0$ makes these shifts much less significant. Unlike existing analytic approximations, the BR estimator can be straightforwardly extended for the case of power spectra from correlated fields, such as temperature and polarization. We discuss challenges to extending the procedure to higher $\ell$ and provide some solutions.

A possible wave effect in the gravitational lensing phenomenon is discussed. We consider the interference of two coherent gravitational waves of slightly different frequencies from a compact binary, due to the gravitational lensing by a galaxy halo. This system shows the modulation of the wave amplitude. The lensing probability of such the phenomenon is of order ${10}^{-5}$ for a high-$z$ source, but it may be advantageous to the observation due to the magnification of the amplitude.

We use a simulated annealing algorithm to find the static field configuration with the lowest energy in a given sector of topological charge for generalized $SU(2)$ Skyrme models. These numerical results suggest that the following conjecture may hold: the symmetries of the soliton solutions of extended Skyrme models are the same as for the Skyrme model. Indeed, this is verified for two effective Lagrangians with terms of order six and order eight in derivatives of the pion fields, respectively, for topological charges $B=1$ up to $B=4$. We also evaluate the energy of these multiskyrmions using the rational maps ansatz. A comparison with the exact numerical results shows that the reliability of this approximation for extended Skyrme models is almost as good as for the pure Skyrme model. Some details regarding the implementation of the simulated annealing algorithm in one and three spatial dimensions are provided.

If all the supersymmetry particles (sparticles) except a light Higgs boson are too heavy to be directly produced at the Large Hadron Collider and Tevatron, a possible way to reveal evidence for supersymmetry is through their virtual effects in other processes. We examine such supersymmetric QCD effects in bottom pair production associated with a light Higgs boson at the Large Hadron Collider and Tevatron. We find that if the relevant sparticles (gluinos and squarks) are well above the TeV scale, too heavy to be directly produced, they can still have sizable virtual effects in this process. For large $\tan \beta$, such residual effects can alter the production rate by as much as 40%, which should be observable in future measurements of this process.

When studying $B$ decays within the standard model (SM), it is customary to use the unitarity of the CKM matrix in order to write the decay amplitudes in terms of only two of the three weak phases which appear in the various diagrams. Occasionally, it is mentioned that those two weak phases can be used in order to describe any decay amplitude, even beyond the standard model. Here we point out that, when describing a generic decay amplitude, the two weak phases can be chosen completely at will, and we study the behavior of the decay amplitudes under changes in the two weak phases chosen as a basis. Of course, physical observables cannot depend on such reparametrizations. This has an impact on discussions of the SM and on attempts to parametrize new physics effects in the decay amplitudes. We illustrate these issues by looking at $B\to \psi K_S$ and the isospin analysis in $B\to \pi \pi$.