In-medium decay widths of hidden and open charm vector mesons in a field theoretic model for composite hadrons

Abstract

We calculate the decay widths of the charmonium states, J/ψ, ψ(3686) and ψ(3770), to [Formula: see text] pairs, as well as the decay width of D* → Dπ, in isospin asymmetric strange hadronic matter, using a field theoretical model for composite hadrons with quark constituents. For this purpose, we use the quark–antiquark pair creation term of the free Dirac Hamiltonian written in terms of the constituent quark field operators, and use explicit charmonium, D, [Formula: see text], D* and π states to evaluate the matrix elements for the charmonium as well as D* decay amplitudes. The medium modifications of the partial decay widths of charmonium to [Formula: see text] pair, arising from the mass modifications of the [Formula: see text] 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, in a model using light quark pair creation in 3P0 state. As in 3P0 model, the decay amplitude in the present model is multiplied with a strength parameter for the light quark pair creation, which is fitted from the observed vacuum decay width. The effects of the isospin asymmetry, the strangeness fraction of the hadronic matter on the masses of the charmonium states and [Formula: see text] 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 [Formula: see text] pairs. The decay width of D* → Dπ in the hadronic matter has also been calculated within the composite quark model in the present work, accounting for the medium modifications of the D and D* masses. The density modifications of the charmonium states and D(D*) mesons, which are observed to be appreciable at high densities, will be of relevance in the compressed baryonic matter (CBM) experiments at the future facility of FAIR, GSI, where charmed hadrons will be produced by annihilation of antiprotons on nuclei. The interactions of the charmonium states and D(D*) with the nuclear medium could lead to the possibility of the formation of exotic bound states of the nuclei with the (excited) charmonium states as well as with D(D*) mesons.