No Arabic abstract
At the chiral restoration/deconfinement transition, most hadrons undergo a Mott transition from being bound states in the confined phase to resonances in the deconfined phase. We investigate the consequences of this qualitative change in the hadron spectrum on final state interactions of charmonium in hot and dense matter, and show that the Mott effect for D-mesons leads to a critical enhancement of the J/Psi dissociation rate. Anomalous J/Psi suppression in the NA50 experiment is discussed as well as the role of the Mott effect for the heavy flavor kinetics in future experiments at the LHC. The status of our calculations of hadron-hadron cross sections using the quark interchange and chiral Lagrangian approaches is reviewed, and an Ansatz for a unification of these schemes is given.
In this paper we analyse the double vector meson production in photon -- hadron ($gamma h$) interactions at $pp/pA/AA$ collisions and present predictions for the $rhorho$, $J/Psi J/Psi$ and $rho J/Psi$ production considering the double scattering mechanism. We estimate the total cross sections and rapidity distributions at LHC energies and compare our results with the predictions for the double vector meson production in $gamma gamma$ interactions at hadronic colliders. We present predictions for the different rapidity ranges probed by the ALICE, ATLAS, CMS and LHCb Collaborations. Our results demonstrate that the $rhorho$ and $J/Psi J/Psi$ production in $PbPb$ collisions is dominated by the double scattering mechanism, while the two - photon mechanism dominates in $pp$ collisions. Moreover, our results indicate that the analysis of the $rho J/Psi$ production at LHC can be useful to constrain the double scattering mechanism.
We study $D$ - meson production at forward rapidities taking into account the non - linear effects in the QCD dynamics and the intrinsic charm component of the proton wave function. The total cross section, the rapidity distributions and the Feynman - $x$ distributions are calculated for $p p$ collisions at different center of mass energies. Our results show that, at the LHC, the intrinsic charm component changes the $D$ rapidity distributions in a region which is beyond the coverage of the LHCb detectors. At higher energies the IC component dominates the $y$ and $x_F$ distributions exactly in the range where the produced $D$ mesons decay and contribute the most to the prompt atmospheric neutrino flux measured by the ICECUBE Collaboration. We compute the $x_F$ - distributions and demonstrate that they are enhanced at LHC energies by approximately one order of magnitude in the $0.2 le x_F le 0.8$ range.
In the framework of the perturbative Quantum Chromodynamics factorization, the cross section of the heavy meson production via the combination of a heavy quark with a light one can be factorized to be the convolution of the combination matrix element, the light quark distribution function, and the hard partonic sub-cross section of the heavy quark production. The partonic distribution and the combination matrix element are functions of a scaling variable, respectively, which is the momentum fraction of the corresponding quark with respect to the heavy meson. We studied the $D^{*pm}$ production in jet via combination in pp collision at the LHC. Our calculation can be summed with the fragmentation contribution, and the total result is comparable with the experimental data. The combination matrix elements can be further studied in various hadron production processes.
We give arguments in favor of the compatibility with standard physics of some large nonleptonic branching fractions in Cabibbo--forbidden $D^+$ decays, contrary to a recent claim in the literature.
We consider the fidelity of the vector meson dominance (VMD) assumption as an instrument for relating the electromagnetic vector-meson production reaction $e + p to e^prime + V + p$ to the purely hadronic process $V + p to V+p$. Analyses of the photon vacuum polarisation and the photon-quark vertex reveal that such a VMD Ansatz might be reasonable for light vector-mesons. However, when the vector-mesons are described by momentum-dependent bound-state amplitudes, VMD fails for heavy vector-mesons: it cannot be used reliably to estimate either a photon-to-vector-meson transition strength or the momentum dependence of those integrands that would arise in calculations of the different reaction amplitudes. Consequently, for processes involving heavy mesons, the veracity of both cross-section estimates and conclusions based on the VMD assumption should be reviewed, e.g., those relating to hidden-charm pentaquark production and the origin of the proton mass.