D mesons in matter and the in-medium properties of charmonium

Abstract

We study the changes in the partial decay widths of excited charmonium states into $D \bar{D}$, when the D meson mass decreases in nuclear matter, taking the internal structure of the hadrons into account. Calculations within the 3P0 model for $\psi(3686)$ and $\psi(3770)$ imply that naive estimates of the in-medium widths based only on phase space are grossly exaggerated. Due to nodes in the wave functions, these states may even become narrow at high densities, if the D meson mass is decreased by about 200 MeV. For the $\chi$ states, we generally expect stronger modifications of the widths. The relevance of the $\chi$ widths for $J/\psi$ suppression in heavy ion collision is discussed. These phenomena could be explored in experiments at the future accelerator facility at GSI.Comment: 12 pages, 3 figures; allowed for two independent oscillator parameters for the charmonium states and D mesons, results are not significantly modified and conclusions remains unaltere

Interaction of slowJ/ψandψ′with nucleons

“…This shift in the energy of the ψ ′ can be important for the estimates of the decay ψ ′ →DD, which becomes possible in nuclear matter due to the shifts in the masses of the D andD mesons [39,40,41,42,43]. The main difference between the nuclear interactions of slow J/ψ and ψ ′ is that for the latter there exist subthreshold scattering processes: the charm-exchange process ψ ′ +N →Λ c +D, the charmonium transition scattering ψ ′ +N →J/ψ+N , and generally additional channels where in the latter process instead of a single nucleon excited states are being produced such as N π, ∆π, etc.…”

Dmesons in nuclear matter: ADNcoupled-channel equations approach

“…However, there are approaches based on effective quark potentials such as in Refs. [10] and [11] which are in a way complementary to these three approaches. We do not discuss those quark-model methods here.…”

Medium modifications of charm and charmonium in high-energy heavy-ion collisions

“…Here, the consequences of in-medium Dmeson masses are two-fold: first, inelastic reaction rates increase due to a larger † Note that for a quantitative assessment, the entropy term in F QQ should be removed. available phase space and second, the DD threshold can move below the charmonium mass, which additionally enables direct decays Ψ → DD [13]. The rate equations are supplemented by initial conditions, N 0 Ψ , for which we take experimental yields from pp extrapolated in centrality by N -N collision scaling and "pre-equilibrium" nuclear absorption.…”