Related papers: Gluonia in QCD with massless quarks
To include the explicit valence gluon degrees of freedom into spectroscopy of the lowest states of heavy quarkonia, we consider, within an adiabatic model, the properties of the lowest hybrid $\bar{Q}Qg$-mesons and estimate the effects of…
A quarkonium-gluonium mixing scheme previously developed to describe the characteristic of the pseudoscalar mesons is applied to axial and tensor mesons. The parameters of the model are determined by fitting the eigenvalues of a mass…
We extract the $Q$-$\bar Q$ potential by using the thermodynamic quantities obtained in lattice gauge calculations. The potential is tested and found to give dissociation temperatures that agree well with those from lattice gauge spectral…
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…
The chiral expansion of the low energy processes $\pi^0\to\gamma\gamma$ and $\eta\to\gamma\gamma$ is reconsidered with particular emphasis on the question of the evaluation of the two low-energy parameters from ${\cal L}^{WZ}_{(6)}$ which…
The recent data for $J/\psi$ hadronic decays from BES raise ``puzzles" about the scalar meson properties, which are different from the naive OZI rule expectation. In this work, we study the implications of a glueball-$Q\bar{Q}$ mixing…
In this paper we study the $\eta'$ in $N_f=2+1+1$ lattice QCD simulations at finite temperature. Results are obtained from the analysis of the gluonic defined topological charge density correlator after gradient flow. Our results indicate…
A new scheme for calculating masses and boost-invariant wave functions of heavy quarkonia is developed in a light-front Hamiltonian formulation of QCD. Only the simplest approximate version with one flavor of quarks and an ansatz for the…
Recently a $J^{PC}=0^{++}$ (X(1812)) state with a mass near the threshold of $\omega$ and $\phi$ has been observed by the BES collaboration in $J/\psi \to \gamma \omega \phi$ decay. It has been suggested that it is a $I^G = 0^+$ state. If…
Theoretical predictions for the $D^0\overline{D^0}$ mixing parameters fall significantly short of experimental measurements, with discrepancies spanning several orders of magnitude. This gap is mainly due to the Glashow-Iliopoulos-Maiani…
Phenomenological evidence and analytic approximations to the QCD ground state suggest a complex gluon condensate structure. Exclusion of elementary fermion excitations by the generation of infinite mass corrections is a consequence. In…
The mass spectra and decay properties of heavy quarkonia are computed in nonrelativistic quark-antiquark Cornell potential model. We have employed the numerical solution of Schr\"odinger equation to obtain their mass spectra using only four…
A simple model for QCD is presented, which is able to reproduce the meson spectrum at low energy. The model is a Lipkin type model for quarks coupled to gluons. The basic building blocks are pairs of quark-antiquarks coupled to a definite…
Decay rates of $c\bar c$ and $b\bar b$ mesons have been studied within the NRQCD formalism. The basic parameters of the formalism have been obtained from different potential schemes studied for the quarkonia spectra. The present results are…
QCD corrections to the electroweak cross section of $\gamma\gamma\to ZZ$ at high energies and small scattering angles have been calculated. The dominant contributions are due to $t$-channel gluon exchange, i.e. photons dissociate into…
We calculate quarkonium spectral functions in a quark-gluon plasma using a potential model based on full QCD lattice calculations of the free energy of static quark-antiquark pair. We estimate the binding energy and the thermal width of…
Comparison of two appropriately chosen screening masses of colour singlet operators in the pure glue QCD plasma indicates that at sufficiently high temperature it contains a weakly-interacting massive quasi-particle with the quantum numbers…
We study gluino decays in the Minimal Supersymmetric Standard Model (MSSM) with squark generation mixing. We show that the effect of this mixing on the gluino decay branching ratios can be very large in a significant part of the MSSM…
I review to which extent the properties of pseudoscalar mesons can be understood in terms of the underlying quark (and eventually gluon) structure. Special emphasis is put on the progress in our understanding of eta-eta' mixing.…
The in-medium masses of the bottomonium ground states [$1S$ ($\Upsilon (1S), \eta_b$) and $1P$ ($\chi_{b0},\chi_{b1}$)] are investigated in the magnetized vacuum (nuclear medium), using the QCD sum rule framework. In QCD sum rule approach,…