Related papers: Gluon-mass effects in quarkonia decays, $e^+e^-$ a…
Quark-gluon decays of heavy paraquarkonia $^1 S_0(\bar Q Q) \to \bar q q g$ are investigated with account of the masses of final quarks. The decay widths and the energy distributions of the final quarks and gluons are calculated in…
Using the expression of the dynamical gluon mass obtained through the operator product expansion we discuss the relevance of gluon mass effects in the decays V -> hadrons (V = J/Psi, Upsilon). Relativistic and radiative corrections are also…
We compute the masses and decay widths of gluonia using QCD spectral sum rules and low-energy theorems. In the scalar sector, one finds a gluonium having a mass $M_G=(1.5\pm 0.2)$ GeV, which decays mainly into the $U(1)_A$ channels…
An effective meson Lagrangian including a scalar glueball is constructed on the base of $U(3)\times U(3)$ chiral symmetry. The glueball is introduced into the meson Lagrangian by using the principle of scale invariance of an effective…
The development of a Modified Perturbation Theory for QCD, introduced in previous works, is continued. The gluon propagator is modified as consequence of a soft gluon pairs condensate in the vacuum. The modified Feynman rules for $\alpha=1$…
Three topics, the self-consistent resummation of the perturbative expansion for thermal Yang-Mills (YM) theory, nonperturbative analysis of Yang-Mills theories in (2+1) dimensions and modification of the Bose distribution for gluons, are…
This is a review of the estimate of the gluonia masses, decay and mixings from QCD spectral sum rules and low-energy theorems. Some phenomenological maximal gluonium-quarkonium mixing shemes in the scalar sector are presented. This talk is…
The phase between three-gluon and one-photon amplitudes in psi(2S) and psi(3770) decays is analyzed.
We consider various special cases of gluon condensates at finite temperature. The gluon condensate for an ideal gas of gluons with a given vacuum expectation value is introduced for the sake of comparison with that calculated using the…
We review the phenomenological and theoretical evidences for dynamical gluon mass generation and the main features of the glueball spectrum in (pure gauge) Yang-Mills theories. The mixing between glueball and conventional $\bar q q$ states…
Masses and decay constants of the scalar quarkonia, $\chi_{Q0} (Q=b,c)$ with quantum numbers $I^G(J^{PC})=0^{+}(0^{++})$ are calculated in the framework of the QCD sum rules approach both in vacuum and finite temperature. The masses and…
We report about a recent calculation of the heavy quarkonium mass and decay width in a quark-gluon plasma, whose temperature T and screening mass m_D satisfy the hierarchy m alpha_s >> pi T >> m alpha_s^2 >> m_D, m being the heavy-quark…
By the use of the gauge/gravity duality, we calculate the imaginary part of heavy quarkonium potential and thermal width with the effect of gluon condensate which is absent in AdS$_{5}$ background. Our results show that the dropping gluon…
I present a more refined analysis of the mass-splittings between the different heavy quarkonia states, using {\it new double ratios} of exponential moments of different two-point functions. Then, I test the validity of the $1/m$-expansion,…
We consider the dynamics of the scalar and pseudoscalar glueballs in the Quark-Gluon Plasma (QGP). By using the instanton model for the QCD vacuum we give the arguments that the nonperturbative gluon-gluon interaction is qualitatively…
Lattice computations with excited SU(3) representations suggest that the confining gluon-gluon interaction complies with the Casimir scaling. The constituent gluon models have also been assuming the Casimir scaling. Inspired in type-II…
The decay of 2-gluon colour singlets in quarks: 2g --> q-qbar +2q-2qbar has been simulated with the Monte-Carlo method, taking into account an effective 1-gluon exchange interaction between the emitted quarks, which was folded with a…
We investigate the hadronic two-body decay modes of the scalar-isoscalar $f_0(1370)$, $f_0(1500)$ and $f_0(1710)$ states as resulting from the mixture of the lowest lying scalar glueball with the isoscalar states of the ground state $^3P_0$…
We establish the factorization formula for scalar Glueball production through radiative decays of vector states of heavy quarkonia, e.g. $J/\psi$, $\psi(2S)$ and $\Upsilon(nS)$, where the Glueball mass is much less than the parent heavy…
We analyze the mixing of the scalar glueball with the scalar-isoscalar quarkonia states above 1 GeV in a non-local covariant constituent approach. Similarities and differences to the point-particle Klein-Gordon limit and to the quantum…