[en] We estimate the energy of the lowest charmonium and upsilon states with hybrid admixtures using the method of QCD Sum Rules. Our results show that the Ψ^'(2S) and Y(3S) states both have about a 50% admixture of hybrid and meson components. From this we find explanations of both the famous ρ-π puzzle for charmonium, and the unusual pattern of σ decays that have been found in Y decays. Moreover, this picture can be used for predictions of heavy quark production with the octet model for RHIC.

[en] We estimate the energy of the lowest charmonium and upsilon states with hybrid admixtures using the method of QCD sum rules. Our results show that the Ψ^'(2S) and Υ(3S) states both have about a 50% admixture of hybrid and meson components. From this we find explanations of both the famous ρ-π puzzle for charmonium and the unusual pattern of σ decays that have been found in Υ decays. Moreover, this picture can be used for predictions of heavy quark production with the octet model for RHIC.

[en] Starting from the QCD action in an instanton-like SU(2) Yang-Mills field theory, we derive equations of motion in Minkowski space. Possible bubble collisions are studied in a 1+1 dimension reduction. We find gluonic structures which might give rise to CMBR effects

[en] Bubble collisions in cosmological phase transitions are explored, taking the non-abelian character of the gauge fields into account. Both the QCD and electroweak phase transitions are considered. Numerical solutions of the field equations in several limits are presented. The investigations reported in this talk have been motivated by an interest in studying cosmological phase transitions quantitatively, taking the non-abelian character of the gauge fields into account. Ultimately, we hope to identify observable consequences of cosmological phase transitions. First-order phase transitions proceed by nucleation of bubbles of the broken phase in the background of the symmetric phase. Bubble collisions are of special interest, as they may lead to observable effects such as correlations in the cosmic microwave background (CMB) or as seeds of galactic and extra-galactic magnetic fields. The quantum chromodynamic (QCD) and the electroweak (EW) phase transitions are both candidates of interest in these respects. The Lagrangian driving both the QCD and the EW phase transitions are essentially known and make it possible to approach the physics of the phase transitions from first principles. However, a difficulty to making reliable predictions is that the fundamental guage fields in both these instances are non-abelian: the gluon field in QCD and the W and Z fields in the EW case. The quantitative role of non-abelian fields in cosmological phase transitions is poorly known and difficult to calculate due to the nonlinearities arising from the non-abelian character of the gauge fields.

[en] We use the method of QCD sum rules to investigate a possible hybrid baryon with the quantum numbers of the Λ. Using a current composed of uds quarks in a color octet and a gluon, a strange hybrid, the Λ_H, is found about 500 MeV above the Λ, and we identify it as the Λ(1600). Using our sigma or glueball model we predict a large branching fraction for the Λ_H→Λ+σ(ππ resonance), and the experimental search for this decay mode could provide a test of the hybrid nature of the Λ(1600)

[en] This is a review of the production of heavy quark states via relativistic heavy ion collisions in RHIC. The heavy quarks here are html-italic^>c, charm quark, and html-italic^>b, bottom quark. The states are charmonium meson states $\Psi \left(nS\right)$, with n = 1,2 and upsilon meson states ${\rm Y}\left(mS\right)$, with m = 1,2,3. Quantum Chromodynamics (QCD) sum rules were used to derive the result that the $\Psi \left(2S\right)$ and ${\rm Y}\left(3S\right)$ are mixed hybrid states, which increase their production cross sections. We also review the $\Psi \left(nS\right)$ and ${\rm Y}\left(mS\right)$ production cross sections via Cu-Cu and Au-Au collisions, which are very important for this review of the production of heavy quark states in RHIC. The possible detection of the Quark Gluon Plasma (QGP) is also reviewed.

[en] Possible cosmic microwave background radiation (CMBR) correlations are estimated for a model in which a Hubble-size magnetic wall is formed during the QCD chiral phase transition. Measurable polarization correlations are found for l values greater than about 1000. It is also found that metric perturbations from the wall could give rise to observable CMBR correlations for large l

[en] We estimate the relative branching ratio of σ to 2π for the decay of the Ψ^'(2S), which we have found to be a mixed charm and hybrid charmonium meson. The external field method and correlators from a previous calculation are used to estimate these decays. We find the σ to 2π branching ratio for Ψ^'(2S) to the J/Ψ(1S) decay to be 0.98, in agreement with an experiment at IHEP-BES.

[en] We propose an analogue of the familiar gap equation for the case of four-quark condensates at finite temperature. The condensates of interest correspond to scalar, vector, pseudoscalar, axial vector, and tensor Dirac structures. Working with correlators at zero chemical potential without factorization, we arrive at coupled equations for these four-quark condensates and the masses of certain light-quark mesons. We study the temperature dependence of the four-quark condensates and masses; in one of our models, factorization of the four-quark condensates is shown to be increasingly violated as the temperature is increased toward T_c. The 2⁺⁺ tensor mesons a₂(1320)-f₂(1270) are identified as especially sensitive probes of the four-quark condensates. (c) 2000 The American Physical Society

[en] The Pomeron, which dominates high energy elastic and diffractive hadronic processes, must be largely gluonic in nature. We use a recent picture of a scalar glueball/sigma system with coupling of the sigma to glue determined from experiment to predict strong peripheral sigma production in the ppπ⁰π⁰ and double-sigma production in the ppπ⁰π⁰π⁰π⁰ channels