In this paper, we perform a global analysis of $\overrightarrow{B}\mathrm{PP}$ and $\mathrm{PV}$ decays with the QCD factorization approach. It is encouraging to observe that the predictions of QCD factorization are in good agreement with experiment. The best fit $\gamma$ is around $79°.$ The penguin-diagram–to–tree-diagram ratio $|P_{\pi \pi }{/T}_{\pi \pi }|$ of ${\pi }^{+}{\pi }^{-}$ decays is preferred to be larger than $\mathrm{0.3.}$ We also show the confidence levels for some interesting channels: $B^0\to {\pi }^0{\pi }^0,$ $K^{+}{K}^{-},$ and $B^{+}\to \omega {\pi }^{+},\omega K^{+}.$ For $\overrightarrow{B}\pi K^{*}$ decays, they are expected to have smaller branching ratios with more precise measurements.

We analyze the impact of recent solar and atmospheric data on the determination of the neutrino oscillation parameters, taking into account that both the solar ${\nu }_e$ and the atmospheric ${\nu }_{\mu }$ may convert to a mixture of active and sterile neutrinos. We use the most recent global solar neutrino data, including the 1496-day Super-K neutrino data sample, and we investigate in detail the impact of the recent Sudbury Neutrino Observatory (SNO) neutral current, spectral, and day/night data by performing also an analysis using only the charged current rate from SNO. We confirm the clear preference of the pure active large mixing angle solution of the solar neutrino problem and obtain that the LOW solution, vacuum oscillation, small mixing angle, and ${\mathrm{j}\mathrm{u}\mathrm{s}\mathrm{t}-\mathrm{s}\mathrm{o}}^2$ solutions are disfavored with a $\Delta {\chi }^2=9,$ 9, 23, 31, respectively. Furthermore, we find that the global solar data constrains the admixture of a sterile neutrino to be less than 44% at 99% C.L. A pure sterile solution is ruled out with respect to the active one at 99.997% C.L. By performing an improved fit of the atmospheric data, we also update the corresponding regions of oscillation parameters. We find that the recent atmospheric Super-K (1489-day) and MACRO data have a strong impact on constraining a sterile component in atmospheric oscillations: if the ${\nu }_{\mu }$ is restricted to the atmospheric mass states only a sterile admixture of 16% is allowed at 99% C.L., while a bound of 35% is obtained in the unconstrained case. Pure sterile oscillations are disfavored with a $\Delta {\chi }^2=34.6\mathrm{}$ compared to the pure active case.

We use a two-body, light-cone pion wave function (which vanishes when one of the constituents carries all of the plus-momentum) to construct a double distribution. We show that the resulting generalized parton distribution has incorrect behavior at the crossover between kinematic regions. Furthermore, the positivity constraints are not respected. On the other hand, the field-theoretic, two-body double distribution gives generalized parton distributions that have a physically correct crossover behavior and respect the positivity constraints independent of the model wave function used. However, the sum rule and polynomiality conditions cannot be satisfied with a two-body wave function alone since Lorentz symmetry is not maintained.

We construct a left-right symmetric (LRS) model in five dimensions which accounts naturally for the lepton flavor parameters. The fifth dimension is described by an orbifold, $S_1{/Z}_2\times Z_2^{\prime },$ with a typical size of order ${\mathrm{TeV}}^{-1}.$ The fundamental scale is of order 25 TeV which implies that the gauge hierarchy problem is ameliorated. In addition the LRS breaking scale is of the order of a few TeV which implies that interactions beyond those of the standard model are accessible to near future experiments. Leptons of different representations are localized around different orbifold fixed points. This explains, through the Arkani-Hamed–Schmaltz mechanism, the smallness of the tau mass compared to the electroweak breaking scale. An additional U(1) horizontal symmetry, broken by small parameters, yields the hierarchy in the charged lepton masses, strong suppression of the light neutrino masses and accounts for the mixing parameters. The model yields several unique predictions. In particular, the branching ratio for the lepton flavor violating process ${\mu }^{-}\to e^{+}{e}^{-}{e}^{-}$ is comparable with its present experimental sensitivity.

We report a search for $B_s^0-\overline{B_s^0}$ oscillations using a sample of $400000$ hadronic $Z^0$ decays collected by the SLD experiment. The analysis takes advantage of the electron beam polarization as well as information from the hemisphere opposite that of the reconstructed B decay to tag the B production flavor. The excellent resolution provided by the pixel CCD vertex detector is exploited to cleanly reconstruct both B and cascade D decay vertices, and tag the B decay flavor from the charge difference between them. We exclude the following values of the $B_s^0-\overline{B_s^0}$ oscillation frequency: $\Delta m_s<4.9\mathrm{}{\mathrm{ps}}^{-1}$ and $7.9<\mathrm{}\Delta m_s<10.3\mathrm{}{\mathrm{ps}}^{-1}$ at the $95\%$ confidence level.

We count the Bogomol’nyi-Prasad-Sommerfield (BPS) states of strings in uniform 3-form fluxes, using supersymmetric quantum mechanics derived from the $\kappa$-symmetric action for D-branes. This problem is relevant to the stringy physics of warped compactifications. We work on a type IIB $T^6/{\mathbf{Z}}_2$ orientifold with an imaginary self-dual, quantized, 3-form flux. Ignoring the orientifold projection, the number of short multiplets living on a single string is the square of the units of the 3-form flux present on the torus; the orientifold removes roughly half of the multiplets. We review the well-known case of a superparticle on $T^2$ as a pedagogical example.

A convenient and general decomposition of the photon self-energy in a magnetized, but otherwise isotropic, medium is given in terms of the minimal set of tensors consistent with the transversality condition. As we show, the self-energy in such a medium is completely parametrized in terms of nine independent form factors, and they reduce to three in the long wavelength limit. We consider in detail an electron gas with a background magnetic field, and, using finite temperature field theory methods, we obtain the one-loop formulas for the form factors, which are exact to all orders in the magnetic field. Explicit results are derived for a variety of physical conditions. In the appropriate limits, we recover the well-known semiclassical results for the photon dispersion relations and the Faraday effect. In more general cases, where the semiclassical treatment or the linear approximation (weak-field limit) are not applicable, our formulas provide a consistent and systematic way for computing the self-energy form factors and, from them, the photon dispersion relations.

Since the thermal history of the universe is unknown before the epoch of primordial nucleosynthesis, the largest temperature of the radiation-dominated phase (the reheating temperature) might have been as low as 1 MeV. We perform a quantitative study of the supersymmetric dark matter relic abundance in cosmological scenarios with low reheating temperature. We show that, for values of the reheating temperature smaller than about 30 GeV, the domains of the supergravity parameter space which are compatible with the hypothesis that dark matter is composed of neutralinos are largely enhanced. We also find a lower bound on the reheating temperature: If the latter is smaller than about 1 GeV neutralinos cannot be efficiently produced in the early universe and then they are not able to explain the present amount of dark matter.

We discuss Strassler’s hypothesis of matching nonperturbative effects in orbifold pairs of gauge theories which are perturbatively planar equivalent. One of the examples considered is the parent $\mathcal{N}=1\mathrm{}\mathrm{SU}\mathrm{}\left(N\right)\mathrm{}$ supersymmetric Yang-Mills theory and its nonsupersymmetric orbifold daughter. We apply two strategies allowing us to study nonperturbative effects: (i) low-energy theorems and (ii) putting the theory on small-size $T^4$ or $R^3\times S^1.$ Then both the parent and daughter theories are weakly coupled and amenable to quasiclassical treatment. In all cases our consideration yields a mismatch between the parent and daughter theories. Thus, regretfully, we present evidence against Strassler’s hypothesis. We discuss in passing a brane picture related to our consideration.

We perform a complete and detailed analysis of the anomalous dipole $\Delta {\kappa }_{\gamma }$ and quadrupole moments $\Delta Q_{\gamma }$ of both $W_L$ and $W_R$ bosons in a supersymmetric left-right model. After a discussion of the mechanism of symmetry breaking in the model, we give complete expressions for the CP-conserving static moments of $W_L$ and $W_R.$ We then perform a numerical analysis of the charged vector bosons moments as functions of the parameters in the soft-breaking supersymmetric variables $m_0,M_{1/2},\mu ,A_0,A_{\mathrm{LR}},$ and $\tan \beta .$ The values for $\Delta {\kappa }_{\gamma }$ and $\Delta Q_{\gamma }$ for the $W_L$ boson can vary from the minimal supersymmetric standard model values. Although these couplings are unlikely to be observed by further analysis of the data at CERN LEP2, they might reach the sensitivity of CERN LHC, and will be observable at a future New Linear Collider, which should reach precision of $\mathcal{O}{(10\mathrm{}}^{-3})$ to $\mathcal{O}{(10\mathrm{}}^{-4}).\mathrm{}$ We also present for the first time complete analytical expressions for the static moments of the $W_R$ boson, including supersymmetric contributions, and discuss possible numerical values for a range of supersymmetric parameters.

We study the consequences of time variations in the scale of grand unification, $M_{\mathrm{U}},$ when the Planck scale and the value of the unified coupling at the Planck scale are held fixed. We show that the relation between the variations of the low energy gauge couplings is highly model dependent. It is even possible, in principle, that the electromagnetic coupling $\alpha$ varies, but the strong coupling ${\alpha }_3$ does not (to leading approximation). We investigate whether the interpretation of recent observations of quasar absorption lines in terms of time variation in $\alpha$ can be accounted for by time variation in $M_{\mathrm{U}}.$ Our formalism can be applied to any scenario where a time variation in an intermediate scale induces, through threshold corrections, time variations in the effective low scale couplings.

We analyze the chargino contributions to $B_d-B_d$ mixing and $\mathrm{CP}$ asymmetry of the $B_d\to J/\psi K_S$ decay, in the framework of the mass insertion approximation. We derive model independent bounds on the relevant mass insertions. Moreover, we study these contributions in supersymmetric models with minimal flavor violation, Hermitian flavor structure, and small $\mathrm{CP}$ violating phases and universal strength Yukawa couplings. We show that, in supersymmetric models with large flavor mixing, the observed values of $\sin 2\beta$ may be entirely due to the chargino–up-squark loops.

We report the results of calculations of pseudoscalar-isoscalar hadronic current correlators using the Nambu–Jona-Lasinio model and the real-time finite-temperature formalism. (This work represents a continuation of results reported previously for other current correlators.) Results are presented for the temperatures range $1.2<~{T/T}_c<~6.0,$ where $T_c$ is the temperature of the confinement-deconfinement transition, which we take to be $T_c=170\mathrm{}\mathrm{MeV}.$ Some resonant features are seen in our calculations. In order to understand the origin of these resonances, we have performed relativistic random phase approximation (RPA) calculations of the temperature-dependent spectrum of the $\eta$ mesons for $T<\mathrm{}{T}_c.$ For the RPA calculations, use is made of a simple model in which we introduce temperature-dependent constituent quark masses calculated in a mean-field approximation and a temperature-dependent confining interaction whose form is motivated by recent studies made using lattice simulations of QCD with dynamical quarks. We also introduce temperature-dependent coupling constants in our generalized NJL model. Our motivation in the latter case is the simulation of the approach to a weakly interacting system at high temperatures and the avoidance of “$\eta$ condensates” which would indicate instability of the ground state of the model. We present some evidence that supports our use of temperature-dependent coupling constants for the NJL model. We suggest that our results may be of interest to researchers who use lattice simulations of QCD to obtain temperature-dependent spectral functions for various hadronic current correlation functions.

We calculate general moments of the lepton energy spectrum in inclusive semileptonic $\overrightarrow{B}{X}_c\mathcal{l}\overline{\nu }$ decay. Moments which allow the determination of $m_b^{1S}$ and ${\lambda }_1$ with theoretical uncertainties $\Delta m_b^{1S}\sim 0.04\mathrm{GeV}$ and $\Delta {\lambda }_1\sim 0.05{\mathrm{GeV}}^2$ are presented. The short distance $1S$ mass is used to extract a mass parameter free of renormalon ambiguities. Moments which are insensitive to $m_b$ and ${\lambda }_1$ and therefore test the size of the ${1/m}_b^3$ matrix elements and the validity of the OPE are also presented. Finally, we give an expression for the total branching ratio with a lower cut on the lepton energy, which allows one to eliminate a source of model dependence in current determinations of $|V_{\mathrm{cb}}|$ from $\overrightarrow{B}{X}_c\mathcal{l}\overline{\nu }$ decay.

The Becker-Becker-Strominger formula, describing the string world-sheet instanton corrections to the four-fermion correlator in the Calabi-Yau compactified type-IIA superstrings, is calculated in the special case of the Calabi-Yau threefold realized in the intersection of two Del Pezzo surfaces. We also derive the selection rules in the supersymmetric GUT of the Pati-Salam type associated with our construction.

We discuss the gravitationally interacting system of a thick domain wall and a black hole. We numerically solve the scalar field equation in the Schwarzschild spacetime and obtain a sequence of static axisymmetric solutions representing thick domain walls. We find that, for the walls near the horizon, the Nambu-Goto approximation is no longer valid.

A generic massive Thirring model in three space-time dimensions exhibits a correspondence with a topologically massive bosonized gauge action associated with a self-duality constraint, and we write down a general expression for this relationship. We also generalize this structure to d dimensions, by adopting the so-called doublet approach, recently introduced. In particular, a nonconventional formulation of the bosonization technique in higher dimensions (in the spirit of $d=3)$ is proposed and, as an application, we show how fermionic (Thirring-like) representations for bosonic topologically massive models in four dimensions may be built-up.

The spectrum of the Hermitian Wilson-Dirac operator is investigated for an arbitrary uniform magnetic field in two dimensions. It can be described by a relativistic analogue of the Harper equation. The index of the overlap Dirac operator is obtained directly from the spectral asymmetry of the relativistic Harper system. It coincides with the topological charge if the field strength is equal to or less than $\pi /2.\mathrm{}$

In spacetimes of dimension greater than four it is natural to consider higher order (in $R)$ corrections to the Einstein equations. In this paper generalized Israel junction conditions for a membrane in such a theory are derived. This is achieved by generalizing the Gibbons-Hawking boundary term. The junction conditions are applied to simple brane world models, and are compared to the many contradictory results in the literature.

We obtain all “regularization parameters” (RPs) needed for calculating the gravitational and electromagnetic self-forces for an arbitrary geodesic orbit around a Schwarzschild black hole. These RP values are required for implementing the previously introduced mode-sum method, which allows a practical calculation of the self-force by summing over contributions from individual multipole modes of the particle’s field. In the gravitational case, we provide here full details of the analytic method and results briefly reported in a recent Letter [Phys. Rev. Lett. 88, 091101 (2002)]. In the electromagnetic case, the RPs are obtained here for the first time.