Related papers: Gluonia in QCD with massless quarks
Heavy quark spin symmetry is useful to make predictions on ratios of decay or production rates of systems involving heavy quarks. The breaking of spin symmetry is generally of the order of $O({\Lambda_{\rm QCD}/m_Q})$, with $\Lambda_{\rm…
We report results of our recent works [1,2] where we where the correlations between the c,b-quark running masses{m}_{c,b}, the gluon condensate<\alpha_s G^2> and the QCD coupling \alpha_s in the MS-scheme from an analysis of the charmonium…
I discuss exclusive production of the $\eta'$, $J/\psi$, and $\chi_c(0^+)$ mesons in $pp$ and $p \bar p$ collisions at high energies. QCD diffractive mechanisms as well as nondiffractive mechanisms are discussed. Different unintegrated…
The energy spectrum of a system containing a static quark anti-quark pair is computed for a wide range of source separations using lattice QCD with $N_\mathrm{f}=2+1$ dynamical flavours. By employing a variational method with a basis…
We calculate the transverse momentum dependence of the medium-induced gluon energy distribution radiated off massive quarks in spatially extended QCD matter. In the absence of a medium, the distribution shows a characteristic mass-dependent…
We calculate the correlation functions of $0^{++}$ $q\bar q$, $s\bar s$ and glueball in the QCD sum rules and obtain the mass matrix where non-diagonal terms are determined by the cross correlations among the three states. Diagonalizing the…
Following a recent work on the effective description of the equations of state for hot QCD obtained from a Hard thermal loop expression for the gluon self-energy, in terms of the quasi-gluons and quasi- quark/anti-quarks with respective…
We study the effect of squark-generation mixing on production and decays of squarks and gluinos at LHC in the Minimal Supersymmetric Standard Model (MSSM). We show that the mixing effects can be very large in a significant range of the…
We present a method which, starting directly from QCD, permits a systematic gauge-invariant expansion to be made for all hard processes involving quarkonia in powers of the quark relative velocity, a small natural parameter for heavy quark…
The partial widths are determined for squark decays to gluinos and quarks, and gluino decays to squarks and quarks, respectively. The widths are calculated including one-loop SUSY-QCD corrections. The corrections amount to $+$30\% to…
The interpretation of virtual gluons as ghosts in the non-linear gluonic structure of QCD permits the formulation and realization of a manifestly gauge-invariant and Lorentz covariant theory of interacting quarks/anti-quarks, for all values…
We fix exactly and uniquely the infrared structure of the full gluon propagator in QCD, not solving explicitly the corresponding dynamical equation of motion. By construction, this structure is an infinite sum over all possible severe…
We compute gluon and quark propagators in 2-colour QCD at large baryon chemical potential mu. The gluon propagator is found to be antiscreened in the superfluid, confined phase and screened in the large-mu, deconfined phase. We present the…
The in-medium behavior of the nucleon spectral density including self-energies is revisited within the framework of QCD sum rules. Special emphasis is given to the density dependence of four-quark condensates. A complete catalog of…
We study the spectra of light mesons as well as the dissociation of a quarkonium and monopole-anti monopole bound state in a gluon condensate background. In order to describe the confining phase we introduce an IR cutoff in two ways, namely…
Using the QCD string theory, we investigate the physical reason of the narrow width of penta-quark baryons in terms of the large gluonic-excitation energy. In the QCD string theory, the penta-quark baryon decays via a gluonic-excited state…
The ultimate aim of high energy heavy ion collisions is to study quark deconfinement and the quark-gluon plasma predicted by quantum chromodynamics. This requires the identification of observables calculable in QCD and measurable in heavy…
The Global Colour Model(GCM) of QCD is used to extract low energy quark-gluon processes from experimental data. The resultant effective quark-quark coupling correlator is compared with that of Jain and Munczek, and with the combined lattice…
Gaussian sum-rules, which are related to a two-parameter Gaussian-weighted integral of a hadronic spectral function, are able to examine the possibility that more than one resonance makes a significant contribution to the spectral function.…
Isospin symmetry breaking in the quark condensates, $< \bar dd> \not= < \bar uu>$, is a fundamental parameter in both the QCD sum rule studies and the chiral perturbation theory. In this article, we apply the QCD sum rule method to treat…