arXiv subjects

K. Martins

Publications and source records attributed to K. Martins.

4 recordsLinked to original sources

arXiv1998

Charmonium dissociation in hot and dense matter

We investigate $J/ψ$ suppression in ultrarelativistic heavy ion collisions within a generalized GLAUBER model and compare results of a hadronic comover scenario with those of a quark plasma scenario where conditions for MOTT dissociation of charmonium are fulfilled locally at the short time scales before hadronization. We study possible consequences for the theoretical description to be drawn from the observation of ``anomalous'' thresholds in the $J/ψ$ suppression pattern by the NA50 collaboration.

hep-ph↗

arXiv1997

Mott mechanism and anomalous charmonium suppression

We investigate a scenario where conditions for Mott dissociation of charmonium are fulfilled locally in ultrarelativistic heavy ion collisions at the short time scales before hadronization and study possible consequences to be drawn from observation of ``anomalous'' thresholds in the J/ψsuppression pattern. We suggest that for a compilation of experiments with different kinematics, variables presently in use to display the observed suppression pattern should be rescaled by the $γ$ factor of the $c\bar c$ state relative to the participant center of mass. This systematics can be tested by inverse kinematics experiments as, e.g., Pb-S collisions and by sampling data sets in p_T and y of the dimuon pairs.

nucl-th↗

arXiv1996

J/Psi and Psi' Suppression in Hadronic Matter

We present a microscopic calculation of the breakup cross sections of $J/ψ$ and $ψ'$ on pions and nucleons as a function of the kinetic energy. These cross sections are used for the investigation of the $J/ψ$ to continuum and $ψ'/J/ψ$ ratios in ultrarelativistic heavy ion collisions. The contribution of produced comoving pions to the $ψ'/J/ψ$ signal is calculated. While this model can account for the data, the uncertainties in the parameter values do not allow to exclude the possibility of additional sources for charmonium absorption, like a resonance gas or the quark gluon plasma.

hep-ph↗

arXiv1994

Quark exchange model for charmonium dissociation in hot hadronic matter

A diagrammatic approach to quark exchange processes in meson-meson scattering is applied to the case of inelastic reactions of the type $(Q\barQ)+(q\barq)\rightarrow (Q\barq) + (q\barQ)$, where $Q$ and $q$ refer to heavy and light quarks, respectively. This string-flip process is discussed as a microscopic mechanism for charmonium dissociation (absorption) in hadronic matter. The cross section for the reaction $J/ψ+ π\to D+ \bar D$ is calculated using a potential model, which is fitted to the meson mass spectrum. The temperature dependence of the relaxation time for the $\J/Psi$ distribution in a homogeneous thermal pion gas is obtained. The use of charmonium for the diagnostics of the state of hot hadronic matter produced in ultrarelativistic nucleus-nucleus collisions is discussed.

hep-ph↗