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 D 0 , Ds and Λ + c 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/D 0 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.

A Study of the Properties of the QCD Phase Diagram in High-Energy Nuclear Collisions

“…In addition, hadronization through coalescence could alter the hadrochemistry distributions of charm quark in various charmed-hadron states which may lead to the reduction in the observed D 0 yields in Au+Au collisions [178]. For instance, hadronization through coalescence can lead to an enhancement of the charmed baryon Λ + c over D 0 yield [179][180][181], and together with the strangeness enhancement in the hot QCD medium and sequential hadronization, can also lead to an enhancement in the charmed strange meson D + s yield relative to D 0 [180][181][182]. The STAR Heavy Flavor Tracker (HFT) with a silicon pixel detector achieved ∼30 µm spacial resolution of the track impact parameter to the primary vertex allows a topological reconstruction of the decay vertices of open charm hadrons.…”

“…However, both calculations fail to fully describe the data and its p T dependence. Figure 15b also shows the comparison to various models with coalescence hadronization of charm quarks [179][180][181][182]. The comparisons suggest coalescence hadronization plays an important role in charm-quark hadronization in the presence of QGP.…”

Hadronization and Charm-Hadron Ratios in Heavy-Ion Collisions

“…Thus, HF spectra simultaneously encompass the at first sight unrelated phenomena described above. An important role is also played by the chemistry of the produced HF hadrons [13][14][15][16][17], which has recently drawn a lot of attention through the observed enhancements in the D s /D 0 and Λ c /D 0 ratios at RHIC [18,19] and the LHC [20,21]. A reliable interpretation of these data requires a hadronization model that satisfies both kinetic and chemical equilibrium in the limit of thermal quark distributions as an input.…”

“…The spatial density, dN/d 3 x, of Cooper-Frye generated thermal light-quark spectra (at midrapidity) from the underlying hydro evolution on the same hypersuface shows a similar behavior. As recombination occurs between partons close to each other in both x and p space, the SMCs (not included in previous studies [16,17] EbyE Langevin-RRM.-To achieve the inclusion of SMCs together with exact c-quark number conservation, we implement the RRM EbyE in the fluid rest frame, seamlessly following the Langevin simulation of c-quark diffusion. Toward this end, we first determine the cquark recombination probability self-consistently from the RRM formalism.…”

Improvement of heavy flavor production in a multiphase transport model updated with modern nuclear parton distribution functions

“…At the high transverse momentum (p T ) region, models [12,13] that include both collisional and radiative energy loss of heavy quarks usually provide a fair description of the R AA from central to peripheral collisions. On the other hand, the evolution of low-p T heavy quarks in the bulk medium is similar to the Brownian motion and can thus be studied with transport approaches based on the Langevin or Boltzmann equation, which has been implemented in the models like POWLANG [14], TAMU [15], Duke [16], BAMPS [17], LBT [18], MC@HQ+EPOS [19], PHSD [20] and Catania [21,22].…”