Role of Glueballs in Non-Perturbative Quark-Gluon Plasma

Discussed is how non-perturbative properties of quark gluon plasma, recently discovered in RHIC experiment, can be related to the change of properties of scalar and pseudoscalar glueballs. We set up a model with the Cornwall-Soni's glueball-gluon interaction, which shows that the pseudoscalar glueball becomes massless above the critical temperature of deconfinement phase transition. This change of properties gives rise to the change of sign of the gluon condensate at $T > T_c$. We discuss the other physical consequences resulting from the drastic change of the pseudoscalar glueball mass above the critical temperature.Comment: 8 pages, 3 figure

A "BPS expansion" for B and D mesons

We analyze consequences of the approximation \mu_\pi^2 -\mu_G^2 << \mu_\pi^2 (a `BPS' limit) for B and D mesons. It is shown that neglecting perturbative effects many power corrections would vanish to all orders in 1/m_Q, in particular those violating heavy flavor symmetry. Among them are corrections to B->D formfactors. A number of relations receive corrections only to the second order expanding around the BPS limit to any order in 1/m_Q, including both f_+ and f_- at zero recoil. This allows an accurate evaluation of {\cal F}_+ for B->D l\nu. Its perturbative renormalization is computed analytically in the required Wilsonian scheme, yielding the dominant 3% enhancement.Comment: 13 pages, LaTeX, two figure

The Two Roads to "Intrinsic Charm" in B Decays

We describe two complementary ways to show the presence of higher order effects in the 1/m_Q expansion for inclusive B decays that have been dubbed "Intrinsic Charm". Apart from the lessons they can teach us about QCD's nonperturbative dynamics their consideration is relevant for precise extractions of |V_{cb}|: for they complement the estimate of the potential impact of 1/m_Q^4 contributions. We draw semiquantitative conclusions for the expected scale of Weak Annihilation in semileptonic B decays, both for its valence and non-valence components.Comment: 17 pages, 3 figure

Darboux-integration of id\rho/dt=[H,f(\rho)]

A Darboux-type method of solving the nonlinear von Neumann equation $i\dot \rho=[H,f(\rho)]$, with functions $f(\rho)$ commuting with $\rho$, is developed. The technique is based on a representation of the nonlinear equation by a compatibility condition for an overdetermined linear system. von Neumann equations with various nonlinearities $f(\rho)$ are found to possess the so-called self-scattering solutions. To illustrate the result we consider the Hamiltonian $H$ of a one-dimensional harmonic oscillator and $f(\rho)=\rho^q-2\rho^{q-1}$ with arbitary real $q$. It is shown that self-scattering solutions possess the same asymptotics for all $q$ and that different nonlinearities may lead to effectively indistinguishable evolutions. The result may have implications for nonextensive statistics and experimental tests of linearity of quantum mechanics.Comment: revtex, 5 pages, 2 eps figures, submitted to Phys.Lett.A infinite-dimensional example is adde

X(1835) as the Lowest Mass Pseudoscalar Glueball and Proton Spin Problem

We consider the parity doublet structure observed in high hadronic excitations within the instanton model for the QCD vacuum. In the conventional approach this doubling phenomenon is treated as a manifestation of the partial restoration of chiral or $U(1)_A$ symmetry. We demonstrate that the suppression of direct instanton contribution to the masses of excited hadrons leads to the partial $U(1)_A$ symmetry restoration in hadron spectrum. The origin of X(1835) resonance observed by BES Collaboration is studied upon the doublet structure. We argue also how X(1835) be interpreted as the lowest pseudoscalar glueball state, and derive its coupling constant to proton. It turns out that this coupling is large and negative. Demonstrated is how this large coupling affects the gluonic contribution to the proton spin.Comment: 12 pages, LaTex, 1 eps-figure, expanded discussion on mechanism of parity doubling in high hadronic excitations, version to appear in Phys.Lett.

Theoretical Aspects of the Heavy Quark Expansion

I give a brief outline of the theoretical framework for the modern treatment of the strong interaction effects in heavy quark decays, based on first principles of QCD. This model-independent approach is required to meet the precision of current and future experiments. Applications to a few problems of particular practical interest are reviewed, including the precise determination of V_{cb} and V_{ub}. I emphasize the peculiarities of simultaneously accounting for the perturbative and power-suppressed effects necessary for accurate predictions.Comment: 18 pages, 2 Figures in the text; LaTeX. Invited lecture presented at the Workshop "Beauty `96", Rome, 17-21 June 1996; Minor stylistic changes, typos corrected, a double reference deleted; to appear in Proc. "Beauty `96" (Nucl. Instrum. & Methods A, 1996

Heavy Quark Expansion and Preasymptotic Corrections to Decay Widths in the 't Hooft Model

We address nonperturbative power corrections to inclusive decay widths of heavy flavor hadrons in the context of the 't Hooft model (two-dimensional QCD at N_c->oo), with the emphasis on the spectator-dependent effects sensitive to the flavor of the spectator. The summation of exclusive widths is performed analytically using the `t Hooft equation. We show that the 1/m_Q expansion of both the Weak Annihilation and Pauli Interference widths coincides with the OPE predictions, to the computed orders. Violation of local duality in the inclusive widths is quantified, and the new example is identified where the OPE prediction and the actual effect are completely saturated by a single final state. The qualitative aspects of quark hadronization emerging from the analysis in the 't Hooft model are discussed. Certain aspects of summation of spectator-independent hadronic weak decay widths are given in more detail, which were not spelled out previously. We also give some useful details of the 1/m_Q expansion in the 't~Hooft model.Comment: 54 pages, 8 figures in the text. Version to be published in Phys. Rev. D. A number of typos are corrected and relevant references added. Clarifications in Conclusions, Appendices 2.1 and 3 are adde

Communication Support Systems Managing the fitness between contextual factors and communication media factors

This study investigates the factors that are crucial for successful communication and hence to the design of Communication Support Systems (CSS). The study focuses on the concept of media richness and attempts to improve our understanding of the factors that influences the fitness between organizational context and the use of communication technology. Thus, the enterprise of mine study has been delineated and focused on the following question: What factors are responsible for successful fit between the communication mediums characteristics and an organizations communicational character? The following three statements represent a sound rather than conclusive answer to the investigated issue. • Firstly, the success of communication depends on the fitness between organizational related factors and communication media related factors. Accordingly, the fitness is expressed in terms of a matching between required richness and provided richness. • Secondly, the fitness between organizational related factors and communication media related factors depends on human factors such as task experience and communication media experience. • Thirdly, the fitness between organizational related factors and communication media related factors depends on human perceived uncertainty rather than task uncertainty as the classical information richness theory presupposes. A case study in the context of a higher school was chosen to be investigated where students teachers, and staff were interviewed with respect to the use of information and communication support