We show that the splitting between the light pseudoscalar and vector meson states is due to the strong short-range attraction in the ${}^1{S}_0$ sector which makes the pion and the kaon light particles. We use a light-cone QCD-inspired model of the mass squared operator with harmonic confinement and a Dirac-delta interaction. We apply a renormalization method to define the model, in which the pseudoscalar ground state mass fixes the renormalized strength of the Dirac-delta interaction.

Using the CCFR data for the Gross–Llewellyn Smith (GLS) sum rule, we extract the strong coupling constant via Borel resummation of the perturbative QCD calculation. The method incorporates the correct nature of the first infrared renormalon singularity, and employs a conformal mapping to improve the convergence of the QCD perturbation expansion. The important twist-four contribution is calculated from resummation of the perturbation theory, which is based on the ansatz that the higher-twist contribution has a cut singularity only along the positive real axis on the complex coupling plane. Thus obtained, the strong coupling constant corresponding to the central GLS experimental value is in good agreement with the world average.

CP-violating asymmetries in the decay $B^0\mathrm{}\left(t\right)\mathrm{}\to {\pi }^{+}{\pi }^{-}$ are a potentially rich source of information about both strong and weak phases. In a previous treatment by the present authors use was made of an assumption about the relative magnitude of tree and penguin amplitudes contributing to this process. This assumption involved an ambiguity in relating the tree amplitude to the amplitude for $\overrightarrow{B}\pi l\nu .$ It is shown here that one can avoid this assumption, which adopted a particular parametrization of tree and penguin amplitudes, and that the results are convention independent.

Using the Moyal star product, we define open bosonic string field theory carefully, with a cutoff, for any number of string oscillators and any oscillator frequencies. Through detailed computations, such as Neumann coefficients for all string vertices, we show that the Moyal star product is all that is needed to give a precise definition of string field theory. The formulation of the theory as well as the computation techniques are considerably simpler in the Moyal formulation. After identifying a monoid algebra as a fundamental mathematical structure in string field theory, we use it as a tool to compute with ease the field configurations for wedge, sliver, and generalized projectors, as well as all the string interaction vertices for perturbative as well as monoid-type nonperturbative states. Finally, in the context of VSFT we analyze the small fluctuations around any D-brane vacuum. We show quite generally that to obtain nontrivial mass and coupling, as well as closed strings, there must be an associativity anomaly. We identify the detailed source of the anomaly, but leave its study for future work.

A system of coupled scalar fields is introduced which possesses a spectrum of massive single-soliton solutions. Some of these solutions are unstable and decay into lower mass stable solitons. Some properties of the solutions are obtained using general principles including conservation of energy and topological charges. Rest energies are calculated via a variational scheme, and the dynamics of the coupled fields are obtained by solving the field equations numerically.

We derive a “generic” inhomogeneous “bridge” solution for a cosmological model in the presence of a real self-interacting scalar field. This solution connects a Kasner-like regime to an inflationary stage of evolution and therefore provides a dynamical mechanism for the quasi-isotropization of the universe. In the framework of a standard Arnowitt-Deser-Misner Hamiltonian formulation of the dynamics and by adopting Misner-Chitrè-like variables, we integrate the Einstein-Hamilton-Jacobi equation corresponding to a “generic” inhomogeneous cosmological model whose evolution is influenced by the coupling with a bosonic field, expected to be responsible for a spontaneous symmetry breaking configuration. The dependence of the detailed evolution of the universe on the initial conditions is then appropriately characterized.

In a previous communication by two of us [B. A. Kniehl and A. Sirlin, Phys. Rev. Lett. 81, 1373 (1998)], the gauge-dependent deviations of the on-shell mass and total decay width from their gauge-independent pole counterparts were investigated at leading order for the Higgs boson of the standard model. In the case of the widths, the deviation was found to diverge at unphysical thresholds, $m_H=2\mathrm{}\sqrt{{\xi }_V}{m}_V$ $\mathrm{}(V=W,Z),$ in the $R_{\xi }$ gauge. In this Brief Report, we demonstrate that these unphysical threshold singularities are properly eliminated if a recently proposed definition of wave-function renormalization for unstable particles is invoked.

The recently observed decay $B^0\to D_s^{+}{\pi }^{-}$ is expected to proceed mainly by means of a tree amplitude in the factorization limit: $B^0\to {\pi }^{-}{(W}^{+}{)}^{*},$ ${(W}^{+}{)}^{*}\to D_s^{+}.$ Under this assumption, we predict the corresponding contribution of the tree amplitude to $B^0\to {\pi }^{+}{\pi }^{-}.$ We indicate the needed improvements in data that will allow a useful estimate of this amplitude with errors comparable to those accompanying other methods. Since the factorization hypothesis for this process goes beyond that proved in most approaches, we also discuss independent tests of this hypothesis.

We describe in some detail the derivation of a power counting formula for the soft-collinear effective theory (SCET). This formula constrains which operators are required to correctly describe the infrared at any order in the ${\Lambda }_{\mathrm{QCD}}/Q$ expansion $(\lambda$ expansion). The result assigns a unique $\lambda$ dimension to SCET graphs solely from vertices, is gauge independent, and can be applied independent of the process. For processes with an OPE the $\lambda$ dimension has a correspondence with a dynamical twist.

Motivated by recent data on $\overrightarrow{B}p\overline{p}K$ decay, we study various charmless three-body baryonic B decay modes, including $\Lambda \overline{p}\pi ,$ ${\Sigma }^0\overline{p}\pi ,$ $p\overline{p}\pi ,$ $p\overline{p}{K}^0,$ in a factorization approach. These modes have rates of order ${10}^{-6}.$ There are two mechanisms for the production of baryon pairs: current produced and transition. The behavior of decay spectra from these baryon production mechanisms can be understood by using QCD counting rules. Predictions on rates and decay spectra can be checked in the near future.

In this paper we study the polarization asymmetries of the final state lepton in the radiative dileptonic decay of the B meson ${(B}_s\to {\mathcal{l}}^{+}{\mathcal{l}}^{-}\gamma )$ in the framework of the minimal supersymmetric standard model (MSSM) and various other unified models within the framework of the MSSM, e.g., MSUGRA, SUGRA (where the condition of universality of scalar masses is relaxed), etc. Lepton polarization, in addition to having a longitudinal component ${(P}_L),$ can have two other components $P_T$ and $P_N$ lying in and perpendicular to the decay plane, which are proportional to $m_{\mathcal{l}}$ and hence are significant for the final state being ${\mu }^{+}{\mu }^{-}$ or ${\tau }^{+}{\tau }^{-}.$ We analyze the dependence of these polarization asymmetries on the parameters of the various models.

We calculate the fluxes and energy spectra of high-energy $(E>\mathrm{}50\mathrm{}\mathrm{GeV})$ neutrinos from the annihilations of supermassive ${(10\mathrm{}}^8\mathrm{GeV}<M<\mathrm{}{10}^{16}\mathrm{GeV}),$ strongly interacting dark matter particles in the core of the Sun. We take all significant aspects of neutrino propagation through matter into account, as well as oscillations in matter and vacuum. We also calculate the resulting event rates in an idealized $1{\mathrm{km}}^3$ ice detector. We find that the signal should be well above background and easily observed by next-generation neutrino detectors such as IceCube.

Unlike ground-based interferometric gravitational wave detectors, large space-based systems will not be rigid structures. When the end stations of the laser interferometer are freely flying spacecraft, the armlengths will change due to variations in the spacecraft positions along their orbital trajectories, so the precise equality of the arms that is required in a laboratory interferometer to cancel laser phase noise is not possible. However, using a method discovered by Tinto and Armstrong, a signal can be constructed in which laser phase noise exactly cancels out, even in an unequal arm interferometer. We examine the case where the ratio of the armlengths is a variable parameter, and compute the averaged gravitational wave transfer function as a function of that parameter. Example sensitivity curve calculations are presented for the expected design parameters of the proposed LISA interferometer, comparing it to a similar instrument with one arm shortened by a factor of 100, showing how the ratio of the armlengths will affect the overall sensitivity of the instrument.

Using a $13.7{\mathrm{fb}}^{-1}$ sample of continuum two-jet $e^{+}{e}^{-}\to q\overline{q}$ events collected with the CLEO detector, we have searched for correlations between Λ and $\overline{\Lambda }$ particles, specifically in cases where the opening angle between the two particles is large and each has momentum $>1\mathrm{}\mathrm{GeV}/c.\mathrm{}$ Such correlations may indicate the presence of baryon number conservation at the primary quark level. A previous CLEO study of ${\Lambda }_c{\overline{\Lambda }}_c$ correlations indicated direct, associated production of primary charmed baryons ${\Lambda }_c:$ $e^{+}{e}^{-}\to c\overline{c}\to {\Lambda }_c{\overline{\Lambda }}_c.$ That effect was not observed in Monte Carlo simulations. Our current search for similar direct, associated production of Λ baryons at the primary quark level ${(e}^{+}{e}^{-}\to s\overline{s}\to \Lambda \overline{\Lambda },$ e.g.) qualitatively indicates a similar effect, although it relies on a Monte Carlo dependent subtraction of background $\Lambda \overline{\Lambda }$ production (based on the default JETSET 7.4 event generator).

We study the apparition of event horizons in accelerated expanding cosmologies. We give a graphical and analytical representation of the horizons using proper distances to coordinate the events. Our analysis is mainly kinematical. We show that, independently of the dynamical equations, all the event horizons tend in the future infinity to a given expression depending on the scale factor that we call asymptotic horizon. We also encounter a subclass of accelerating models without horizons. When the ingoing null geodesics do not change concavity in its cosmic evolution we recover the de Sitter and quintessence-Friedmann-Robertson-Walker models.

We consider a toy universe containing conventional matter and an additional real scalar field, and discuss how the requirements of gauge and diffeomorphism invariance essentially single out a particular set of theories which might describe such a world at low energies. In these theories, fermion masses and g factors, as well as the electromagnetic coupling, turn out to be scalar field dependent; fermion charges and the gravitational coupling might be assumed to be constant. We then proceed to study the impact of a time variation of the scalar field on measurements of atomic spectra at high redshifts. Light propagation is not affected by a sufficiently slow change of the fine structure constant, but changes of the latter as well as variations of fermion masses and g factors do affect the observed atomic spectra. Finally, we prove the independence of these predictions on the chosen conformal frame in a further attempt to address differing views about the subject expressed in the literature.

The quantum interest conjecture of Ford and Roman asserts that any negative-energy pulse must necessarily be followed by an overcompensating positive-energy one within a certain maximum time delay. Furthermore, the minimum amount of over-compensation increases with the separation between the pulses. In this paper we first study the case of a negative-energy square pulse followed by a positive-energy one for a minimally coupled, massless scalar field in two-dimensional Minkowski space. We obtain explicit expressions for the maximum time delay and the amount of over-compensation needed, using a previously developed eigenvalue approach. These results are then used to give a proof of the quantum interest conjecture for massless scalar fields in two dimensions, valid for general energy distributions.

In this work we compute the spectra, waveforms, and total scalar energy radiated during the radial infall of a small test particle coupled to a scalar field into a d-dimensional Schwarzschild–anti-de Sitter black hole. We focus on $d=4,$ 5, and 7, extending the analysis we have done for $d=3.\mathrm{}$ For small black holes, the spectra peaks strongly at a frequency $\omega \sim d-1,$ which is the lowest pure anti–de Sitter (AdS) mode. The waveform vanishes exponentially as $\overrightarrow{t}\infty ,$ and this exponential decay is governed entirely by the lowest quasinormal frequency. This collision process is interesting from the point of view of the dynamics itself in relation to the possibility of manufacturing black holes at CERN LHC within the brane world scenario, and from the point of view of the AdS/CFT conjecture, since the scalar field can represent the string theory dilaton, and $4,$ $5,$ and $7$ are dimensions of interest for the AdS/CFT correspondence.

By using the thermodynamic theory of irreversible processes and Einstein general relativity, a cosmological model is proposed where the early universe is considered as a mixture of a scalar field with a matter field. The scalar field refers to the inflaton while the matter field to the classical particles. The irreversibility is related to a particle production process at the expense of the gravitational energy and of the inflaton energy. The particle production process is represented by a nonequilibrium pressure in the energy-momentum tensor. The nonequilibrium pressure is proportional to the Hubble parameter and its proportionality factor is identified with the coefficient of bulk viscosity. The dynamic equations of the inflaton and the Einstein field equations determine the time evolution of the cosmic scale factor, the Hubble parameter, the acceleration and of the energy densities of the inflaton and matter. Among other results it is shown that in some regimes the acceleration is positive which simulates inflation. Moreover, the acceleration decreases and tends to zero in the instant of time where the energy density of matter attains its maximum value.