Early universe models for the origin of structure typically produce a spectrum of initial fluctuations with a mixture of adiabatic and isocurvature perturbations. Using the observed anisotropies of the cosmic microwave backgound, the matter power spectra from large scale structure surveys and the luminosity distance vs. redshift relation from supernovae of type Ia, we obtain strong bounds on the possible cold dark matter/baryon as well as neutrino isocurvature contributions to the primordial fluctations in the Universe. Neglecting the possible effects of spatial curvature and tensor perturbations, we perform a Bayesian likelihood analysis with 13 free parameters, including independent spectral indexes for each of the modes and for their cross-correlation angle. We find that around a pivot wave number of $k=0.05h{\mathrm{M}\mathrm{p}\mathrm{c}}^{-1}$ the amplitude of the correlated isocurvature component cannot be larger than about 60% for the cold dark matter mode, 40% for the neutrino density mode, and 30% for the neutrino velocity mode, at two sigma. In the first case, our bound is larger than the WMAP first-year result, presumably because we prefer not to include any data from Lyman-$\alpha$ forests, but then obtain large blue spectral indexes for the nonadiabatic contributions. We also translate our bounds in terms of constraints on double inflation models with two uncoupled massive fields.

We discuss the gamma-ray signal from dark matter annihilation in our Galaxy and in external objects, namely, the Large Magellanic Cloud, the Andromeda Galaxy (M31), and M87. We derive predictions for the fluxes in a low energy realization of the minimal supersymmetric standard model and compare them with current data from EGRET, CANGAROO-II, and HEGRA and with the capabilities of new-generation satellite-borne experiments, like GLAST, and ground-based Čerenkov telescopes, like VERITAS. We find fluxes below the level required to explain the possible indications of a $\gamma$-ray excess shown by CANGAROO-II (toward the galactic center) and HEGRA (from M87). As far as future experiments are concerned, we show that only the signal from the galactic center could be accessible to both satellite-borne experiments and to atmospheric Čerenkov telescopes (ACTs), even though this requires very steep dark matter density profiles.

We study the effect of a violation of the strong equivalence principle (SEP) on the cosmic microwave background (CMB). Such a violation would modify the weight of baryons in the primordial gravitational potentials and hence their impact in the establishment of the photon-baryon plasma acoustic oscillations before recombination. This cosmological Nordtvedt effect alters the odd peaks height of the CMB temperature anisotropy power spectrum. A gravitational baryonic mass density of the Universe may already be inferred at the first peak scale from the analysis of Wilkinson microwave anisotropy probe (WMAP) data. Experimental constraints on a primordial SEP violation are derived from a comparison with the Universe’s inertial baryonic mass density measured either in a full analysis of the CMB, or in the framework of the standard big bang nucleosynthesis (BBN).

We present explicit formulas for the SU(3) Clebsch-Gordan coefficients that are relevant for the couplings of large $N_c$ baryons to mesons. In particular, we compute the Clebsch-Gordan series for the coupling of the octet (associated with mesons, and remains the correct representation at large $N_c$) to the large $N_c$ analogs of the baryon octet and decuplet representations.

In soliton models expressed in terms of the nonlinear chiral field, the electric current has an anomalous gauge-field contribution as the baryon current does. We study the spin polarized Skyrmions coupled with the electromagnetic field via the gauged Wess-Zumino term and calculate configurations of the Skyrmion and the gauge field with boundary conditions to ensure the physical charge number for baryons. Although the electromagnetic field via the gauged Wess-Zumino term affects physical quantities in small amounts, we find that the magnetic field forms a dipole structure owing to a circular electric current around the spin-quantization axis of the soliton. This is understood on an analogy with the Meissner effect in the super conductor. The electric-charge distributions turn out to have characteristic structures depending on the total charge, which suggests the intrinsic deformation of baryons due to orbital motions of the constituents.

Two new sum rules were recently discovered by Le Yaouanc et al. by applying the operator product expansion to the nonforward matrix element of a time-ordered product of $b\to c$ currents in the heavy-quark limit of QCD. They lead to the constraints ${\sigma }^2>5{\rho }^2/4$ and ${\sigma }^2>3({\rho }^2{)}^2/5+4{\rho }^2/5$ on the curvature of the $\overline{B}\to D^{(*)}$ Isgur-Wise function, both of which imply the absolute lower bound ${\sigma }^2>15/16$ when combined with the Uraltsev bound ${\rho }^2>3/4$ on the slope. This paper calculates order ${\alpha }_s$ corrections to these bounds, increasing the accuracy of the resultant constraints on the physical form factors. The latter may have implications for the determination of $|V_{cb}|$ from exclusive semileptonic $B$ meson decays.

We extend the construction of lattice chiral gauge theories based on non-perturbative gauge fixing to the non-Abelian case. A key ingredient is that fermion doublers can be avoided at a novel type of critical point which is only accessible through gauge fixing, as we have shown before in the Abelian case. The new ingredient allowing us to deal with the non-Abelian case as well is the use of equivariant gauge fixing, which handles Gribov copies correctly, and avoids Neuberger’s no-go theorem. We use this method in order to gauge fix the non-Abelian group (which we will take to be $SU(N)$) down to its maximal Abelian subgroup. Obtaining an undoubled, chiral fermion content requires us to gauge-fix also the remaining Abelian gauge symmetry. This modifies the equivariant Becchi-Rouet-Stora-Tyutin (BRST) identities, but their use in proving unitarity remains intact, as we show in perturbation theory. On the lattice, equivariant BRST symmetry as well as the Abelian gauge invariance are broken, and a judiciously chosen irrelevant term must be added to the lattice gauge-fixing action in order to have access to the desired critical point in the phase diagram. We argue that gauge invariance is restored in the continuum limit by adjusting a finite number of counter terms. We emphasize that weak-coupling perturbation theory applies at the critical point which defines the continuum limit of our lattice chiral gauge theory.

We address the old difficulty in accommodating the scalar quark-antiquark confining potential together with chiral symmetry breaking. We develop a quark confining potential inspired in the QCD scalar flux tube. The coupling to quarks consists in a double vector vertex. We study the Dirac and spin structure of this potential. In the limit of massless quarks, the quark vertex is vector. Nevertheless, symmetry breaking generates a new scalar quark vertex. In the heavy quark limit, the coupling is mostly scalar. We solve the mass gap equation and find that this potential produces spontaneous chiral symmetry breaking for light quarks. The quantitative results of this model are encouraging.

Since effective potentials derived from Feynman diagrams are naturally given in momentum space, we formulate the nonrelativistic Coulomb problem entirely in momentum representation. We give momentum wave functions for all quantum numbers in one-dimensional integrals, even though they can be evaluated. Angular momentum decomposed Green's functions are then compactly represented. We apply this formalism to investigate the next to next leading order charm effects on 1S bottomonium level shift. Our one insertion results are given completely in analytic form and numerically agree with previous results. Our two insertion results are also in agreement. The net effect of finite charm mass is to decrease the bottom mass by 33 MeV, as determined through the measured 1S energy.

Using the SU(3) flavor symmetry, we construct the effective chiral Lagrangians for the light and heavy pentaquarks. With the correction from the nonzero current quark mass, we derive the Gell-Mann–Okubo type relations for various pentaquark multiplet masses. We also derive Coleman-Glashow relations for antisextet heavy pentaquark magnetic moments. We study possible decays of pentaquarks into conventional hadrons and interactions between and within various pentaquark multiplets and derive their coupling constants in the SU(3) flavor symmetry limit. Possible kinematically allowed pionic decay modes are pointed out. Finally we discuss the possible mixing between different pentaquark multiplets induced by the quark mass which breaks SU(3) symmetry. The pentaquark decay patterns receive correction from this breaking effect.

We calculate the nonzero (naïve) T-odd transverse momentum dependent transversity distribution $h_1^{\perp }(x,{\mathbf{k}}_{\perp }^2)$ of the pion in a quark-spectator-antiquark model. The final-state interaction is modeled by the approximation of one gluon exchange between the quark and the antiquark spectator. Using our model result we estimate the unsuppressed $\cos 2\varphi$ azimuthal asymmetry in unpolarized ${\pi }^{-}p$ Drell-Yan process. We find that the transverse momentum dependence of $h_1^{\perp }(x,{\mathbf{k}}_{\perp }^2)$ of the pion is the same as that of $h_1^{\perp }(x,{\mathbf{k}}_{\perp }^2)$ of the proton calculated from the quark-scalar-diquark model, although the $x$ dependencies of them are different from each other. This suggests a connection between $\cos 2\varphi$ asymmetries in Drell-Yan processes with different initial hadrons.

We point out that the spectrum of pseudoscalar and scalar mesons exhibits a quasidegenerate chiral nonet in the energy region around 1.4 GeV whose scalar component has a slightly inverted spectrum. Based on the empirical linear rising of the mass of a hadron with the number of constituent quarks which yields a mass around 1.4 GeV for tetraquarks, we conjecture that this quasichiral nonet arises from the mixing of a chiral nonet composed of tetraquarks with conventional $\overline{q}q$ states. We explore this possibility in the framework of a chiral model assuming a tetraquark chiral nonet around 1.4 GeV with chiral symmetry realized directly. We stress that $U_A(1)$ transformations can distinguish $\overline{q}q$ from tetraquark states, although it cannot distinguish specific dynamics in the later case. We find that the measured spectrum is consistent with this picture. In general, pseudoscalar states arise as mainly $\overline{q}q$ states but scalar states turn out to be strong admixtures of $\overline{q}q$ and tetraquark states. We work out also the model predictions for the most relevant couplings and calculate explicitly the strong decays of the $a_0(1450)$ and $K_0^{*}(1430)$ mesons.

Upper limits on the ${\overline{\nu }}_e$ flux at the Sudbury Neutrino Observatory have been set based on the ${\overline{\nu }}_e$ charged-current reaction on deuterium. The reaction produces a positron and two neutrons in coincidence. This distinctive signature allows a search with very low background for ${\overline{\nu }}_e$’s from the Sun and other potential sources. Both differential and integral limits on the ${\overline{\nu }}_e$ flux have been placed in the energy range from 4–14.8 MeV. For an energy-independent ${\nu }_e\to {\overline{\nu }}_e$ conversion mechanism, the integral limit on the flux of solar ${\overline{\nu }}_e$’s in the energy range from 4–14.8 MeV is found to be ${\Phi }_{{\overline{\nu }}_e}\le 3.4\times {10}^4{\mathrm{c}\mathrm{m}}^{-2}{\mathrm{s}}^{-1}$ (90% C.L.), which corresponds to 0.81% of the standard solar model ${}^8\mathrm{B}$ ${\nu }_e$ flux of $5.05\times {10}^6{\mathrm{c}\mathrm{m}}^{-2}{\mathrm{s}}^{-1}$, and is consistent with the more sensitive limit from KamLAND in the 8.3–14.8 MeV range of $3.7\times {10}^2{\mathrm{c}\mathrm{m}}^{-2}{\mathrm{s}}^{-1}$ (90% C.L.). In the energy range from 4–8 MeV, a search for ${\overline{\nu }}_e$’s is conducted using coincidences in which only the two neutrons are detected. Assuming a ${\overline{\nu }}_e$ spectrum for the neutron induced fission of naturally occurring elements, a flux limit of ${\Phi }_{{\overline{\nu }}_e}\le 2.0\times {10}^6{\mathrm{c}\mathrm{m}}^{-2}{\mathrm{s}}^{-1}$ (90% C.L.) is obtained.

We report on the inclusive branching fractions of $B^{-}$ and of ${\overline{B}}^0$ mesons decaying to $D^{0}X$, ${\overline{D}}^{0}X$, $D^{+}X$, $D^{-}X$, $D_s^{+}X$, $D_s^{-}X$, ${\Lambda }_c^{+}X$, ${\overline{\Lambda }}_c^{-}X$, based on a sample of $88.9\times {10}^6$ $B\overline{B}$ events recorded with the BABAR detector at the ${\rm Y}(4S)$ resonance. Events are selected by completely reconstructing one $B$ and searching for a reconstructed charmed particle in the rest of the event. We measure the number of charmed and of anticharmed particles per $B$ decay and derive the total charm yield per $B^{-}$ decay $n_c^{-}=1.313\pm 0.037\pm {0.062}_{-0.042}^{+0.063}$ and per ${\overline{B}}^0$ decay $n_c^0=1.276\pm 0.062\pm {0.058}_{-0.046}^{+0.066}$, where the first uncertainty is statistical, the second is systematic, and the third reflects the charm branching-fraction uncertainties.

Orbifold compactification of heterotic ${\mathrm{E}}_8\times {\mathrm{E}}_8^{\prime }$ string theory is a source for promising grand unified model building. It can accommodate the successful aspects of grand unification while avoiding problems like doublet-triplet splitting in the Higgs sector. Many of the phenomenological properties of the four-dimensional effective theory find an explanation through the geometry of compact space and the location of matter and Higgs fields. These geometrical properties can be used as a guideline for realistic model building.

The Ashtekar-Krishnan energy-balance law for dynamical horizons, expressing the increase in mass-energy of a general black hole in terms of the infalling matter and gravitational radiation, is expressed in terms of general trapping horizons, allowing the inclusion of null (isolated) horizons as well as spatial (dynamical) horizons. This first law of black-hole dynamics is given in differential and integral forms, regular in the null limit. An effective gravitational-radiation energy tensor is obtained, providing measures of both ingoing and outgoing, transverse and longitudinal gravitational radiation on and near a black hole. Corresponding energy-tensor forms of the first law involve a preferred time vector which plays the role for dynamical black holes which the stationary Killing vector plays for stationary black holes. Identifying an energy flux, vanishing if and only if the horizon is null, allows a division into energy-supply and work terms, as in the first law of thermodynamics. The energy supply can be expressed in terms of area increase and a newly defined surface gravity, yielding a Gibbs-like equation, with a similar form to the so-called first law for stationary black holes. A Clausius-like relation suggests a definition of geometric entropy flux. Taking entropy as $\mathrm{\text{area}}/4$ for dynamical black holes, it is shown that geometric entropy is conserved: The entropy of the black hole equals the geometric entropy supplied by the infalling matter and gravitational radiation. The area or entropy of a dynamical horizon increases by the so-called second law, not because entropy is produced, but because black holes classically are perfect absorbers.

A scalar field interacting differently with dark matter and baryons may explain why their ratio is of order unity today. We provide three working examples, checking them against the observations of Cosmic Microwave Background, (CMB), Large Scale Structure, supernovae Ia, and post-Newtonian tests of gravity. Such a scenario could make life much easier for supersymmetric dark matter candidates.

We investigate two-loop gluino corrections to the effective Lagrangian for $b\to s+\gamma (g)$ in the minimal supersymmetric extension of the standard model (MSSM) at large $\tan \beta$, including the contributions in which quark flavor change is mediated by charginos. Using the translation invariance of loop momenta and the Ward-Takahashi identities that are required by the $SU(3{)}_c\times U(1{)}_{em}$ gauge invariance, we simplify our expressions to concise forms. As an example, we discuss two-loop gluino corrections to the $CP$ asymmetry of inclusive $B\to X_s\gamma$ decay in $CP$ violating MSSM.

We present an improved partial wave analysis of the dominant lightest supersymmetric particle (LSP) annihilation channel to a fermion-antifermion pair which avoids the nonrelativistic expansion being therefore applicable near thresholds and poles. The method we develop allows for contributions of any partial wave in the total angular momentum $J$ in contrast to partial wave analyses in terms of the orbital angular momentum $L$ of the initial state, which is usually truncated to $p$ waves, and yields very accurate results. The method is formulated in such a way as to allow easy handling of $CP$-violating phases residing in supersymmetric parameters. We apply this refined partial wave technique in order to calculate the neutralino relic density in the constrained minimal supersymmetric standard model (CMSSM) in the presence of $CP$-violating terms occurring in the Higgs-mixing parameter $\mu$ and trilinear $A$ coupling for large $\tan \beta$. The inclusion of $CP$-violating phases in $\mu$ and $A$ does not upset significantly the picture, and the annihilation of the LSPs to a $b\overline{b}$, through Higgs exchange, is still the dominant mechanism in obtaining cosmologically acceptable neutralino relic densities in regions far from the stau coannihilation and the “focus point.” Significant changes can occur if we allow for phases in the gaugino masses and, in particular, the gluino mass.

We have extended our program of QCD simulations with an improved Kogut-Susskind quark action to a smaller lattice spacing, approximately 0.09 fm. Also, the simulations with $a\approx 0.12$  fm have been extended to smaller quark masses. In this paper we describe the new simulations and computations of the static quark potential and light hadron spectrum. These results give information about the remaining dependences on the lattice spacing. We examine the dependence of computed quantities on the spatial size of the lattice, on the numerical precision in the computations, and on the step size used in the numerical integrations. We examine the effects of autocorrelations in “simulation time” on the potential and spectrum. We see possible effects of decays, or coupling to two-meson states in the $0^{++}$ and $1^{+}$ meson propagators. A state consistent with $\pi +K$ is seen as a “parity partner” in the Goldstone kaon propagator, and we make a preliminary mass computation for a radially excited $0^{-}$ meson.