Charmed hadrons from coalescence plus fragmentation in relativistic nucleus-nucleus collisions at RHIC and LHC

Abstract

In a coalescence plus fragmentation approach we calculate the heavy baryon/meson ratio and the pT spectra of charmed hadrons D0, Ds and Λc+ in a wide range of transverse momentum from low pT up to about 10 GeV and discuss their ratios from RHIC to LHC energies without any change of the coalescence parameters. We have included the contribution from decays of heavy hadron resonances and also the one due to fragmentation of heavy quarks which do not undergo the coalescence process. The coalescence process is tuned to have all charm quarks hadronizing in the pT→ 0 limit and at finite pT charm quarks not undergoing coalescence are hadronized by independent fragmentation. The pT dependence of the baryon/meson ratios are found to be sensitive to the masses of coalescing quarks, in particular the Λc/ D0 can reach values of about 1 ÷ 1.5 at pT≈3 GeV, or larger, similarly to the light baryon/meson ratio like p/ π and Λ/ K, however a marked difference is a quite weak pT dependence with respect to the light case, such that a larger value at intermediate pT implies a relatively large value also for the integrated yields. A comparison with other coalescence model and with the prediction of thermal model is discussed.