Sunday, August 4, 2013

1308.0202 (Amruta Mishra et al.)

Charmonium decay widths in matter in a field theoretic model of
composite hadrons

Amruta Mishra, S. P. Misra
We calculate the decay widths of the charmonium states, $J/\psi$, $\psi (3686)$ and $\psi(3770)$, to $D\bar D$ pairs in isospin asymmetric strange hadronic matter, using a field theoretical model for composite hadrons with quark constituents. For this purpose we use a quark antiquark pair creation term that arises within the model, and then use explicit charmonium and $D$ and $\bar {D}$ states to evaluate the decay amplitudes. The medium modifications of these partial decay widths, arising from the mass modifications of the $D(\bar D)$ and the charmonium states calculated in a chiral effective model, are also included. The results of the present investigations are then compared with the decay widths computed earlier, using an ad hoc light quark pair creation in $^3P_0$ state. The effects of the isospin asymmetry, the strangeness fraction of the hadronic matter on the masses of the charmonium states and $D(\bar D)$ mesons and hence on the decay widths, have also been studied. The isospin asymmetry effect is observed to be dominant for high densities, leading to appreciable difference in the decay channels of the charmonium to $D^+ D^-$ and $D^0 \bar {D^0}$ pairs. The density modifications of the decay widths of the charmonium states should show up in experimental observables, like the production of the $J/\psi$ and open charm mesons, in asymmetric heavy ion collisions in the compressed baryonic matter (CBM) experiments at the future facility of FAIR, GSI.
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