We investigate the charm hadron production in relativistic heavy-ion collisions with the quark combination model. The $p_{T}$ dependencies of the charm baryon to meson ratios such as $\frac{Λ_{c}+\barΛ_{c}}{D^{0}+\bar{D}^{0}}$, $\frac{Λ_{c}+\barΛ_{c}}{D^{+}+D^{-}}$ and $\frac{Λ_{c}+\barΛ_{c}}{D_{s}^{+}+D_{s}^{-}}$ in Au+Au collisions at 200 GeV are obtained. The charm baryon enhancement in the intermediate $p_{T}$ range is very prominent, which further, together with the strangeness enhancement, affect the charm hadron ratios and lead to a $\sim17%$ larger charm cross-section given by PHENIX. The dependencies of the charm hadron ratios on energy, centrality, and other parameters are also investigated. Predictions of the charm hadron ratios for the upgrade of RHIC and for LHC are presented.
In this work, we extended our statistical model with charmed and bottomed hadrons, and fit the quark creational probabilities for the heavy quarks, using low energy inclusive charmonium and bottomonium data. With the finalized fit for all the relevant types of quarks (up, down, strange, charm, bottom) at the energy range from a few GeV up to a few tens of GeV's, the model is now considered complete. Some examples are also given for proton-proton, pion-proton, and proton-antiproton collisions with charmonium, bottomonium, and open charm hadrons in the final state.
Strangeness and charm in quark-gluon hadronization
本文对相对论性重离子碰撞中的软强子产生进行了理论研究。我们探讨了膨胀的QGP火球强子化的原理，并了解它的性质。大部分正在进行的努力是证明一个QGP强子化模型的有效性，该模型准确地描述了粒子产生数据。我们从RHIC上62.4GeV的Au-Au碰撞中的多奇异强子的中心性研究开始。我们发现统计强子化模型（SHM）很好地描述了QGP强子化中的粒子产生。对于所有的中心性，物理性质是相容的，较早提出的临界强子化压力建议普遍强子化条件QGP。LHC中的重离子碰撞对SHM在TeV能量尺度上描述粒子产生提出了新的挑战。我们表明，化学非平衡模型给出了一个很好的描述在铅-铅碰撞在2.76 TeV的强子生产一致的中心性的函数。此外，模型参数假设的预期值建议在较低的能量以前的研究。夸克-胶子等离子体火球在相同的强子化条件下发生强子化，即共同的临界压力、熵和能量密度。在大型强子对撞机的能量下，预计会产生大量的粲，因此将粲纳入目前对粒子产生的描述是至关重要的。我们提出了一个升级的SHARE与CHARM计划，量化的魅力的影响，较轻的强子的产额和物理性质的强子化火球。除了光味（$u,d,s$），SHARE with CHARM还描述了粲强子的产生和衰变。我们观察到，根据目前的实验结果，粲衰变主要影响多奇异粒子的产额。
Transport and Langevin equations are employed to study hadronic medium effects on charmonium elliptic flows in heavy-ion collisions. In Pb-Pb collisions, the anisotropic energy density of the quark-gluon plasma (QGP) in the transverse plane is transformed into hadron momentum anisotropy after the phase transition. Charmonia with high transverse momentum $p_T$ are produced via the primordial hard process and undergo different degrees of dissociation along different paths in the QGP. They then scatter with light hadrons in the hadron phase. Both contributions to the charmonium elliptic flows are…
Heavy flavor supplies a chance to constrain and improve the hadronization mechanism. We have established a sequential coalescence model with charm conservation and applied it to the charmed hadron production in heavy ion collisions. The charm conservation enhances the earlier hadron production and suppresses the later production. This relative enhancement (suppression) changes significantly the ratios between charmed hadrons in heavy ion collisions.
We study the production of multi-charmed hadrons by recombination in heavy ion collisions by focusing on the production of $Ξ_{cc}$, $Ξ_{cc}^*$, $Ω_{scc}$, $Ω_{scc}^*$, $Ω_{ccc}$ baryons and X(3872) mesons. Starting from the estimation of yields for those hadrons at chemical freeze-out in both the statistical and coalescence model, we evaluate their transverse momentum distributions at mid-rapidity in the coalescence model. We show that yields of multi-charmed hadrons in heavy ion collisions at RHIC and LHC are large enough, and thereby not only multi-charmed hadrons observed so far, e.g., the…
We study the production of charmed hadrons $D^{0}$ and $Λ_c^+$ in relativistic heavy-ion collisions using an improved quark coalescence model. In particular, we extend the usual coalescence model by letting a produced hadron to have the same velocity as the center-of-mass velocity of coalesced constituent quarks during hadronization to take into account the effect of collective flow in produced quark-gluon plasma. This results in a shift of charmed resonances of higher masses to larger transverse momenta ($p_T^{}$). Requiring all charm quarks of very low $p_T^{}$ to be converted to hadrons via…
Using a quark combination model with the equal-velocity combination approximation, we study the production of hadrons with strangeness and charm flavor quantum numbers in Pb+Pb collisions at $\sqrt{s_{NN}}=$5.02 TeV. We present analytical expressions and numerical results for these hadrons' transverse momentum spectra and yield ratios. Our numerical results agree well with the experimental data available. The features of strange and charm hadron production in the quark--gluon plasma at the early stage of heavy ion collisions are also discussed.
In relativistic nuclear collisions the production of hadrons with light (u,d,s) quarks is quantitatively described in the framework of the Statistical Hadronization Model (SHM). Charm quarks are dominantly produced in initial hard collisions but interact strongly in the hot fireball and thermalize. Therefore charmed hadrons can be incorporated into the SHM by treating charm quarks as 'impurities' with thermal distributions, while the total charm content of the fireball is fixed by the measured open charm cross section. We call this model SHMc and demonstrate that with SHMc the measured multipl…
Heavy quarks are initially produced in nuclear collisions and the number is conserved during the evolution of the system. We establish a sequential coalescence model with charm conservation and apply it to charmed hadron production at RHIC and LHC energies. The charm conservation enhances the earlier formed hadrons and reduces the later formed ones, which leads to a $D_s/D^0$ enhancement and a $Λ_c/D^0$ suppression. The mass dependence of the sequential hadron formation provides us a new tool for studying the quark-gluon plasma hadronization in high energy nuclear collisions.
Out-of-equilibrium contributions to charm hadrons in a fluid-dynamic approach
Universität Heidelberg（海德堡大学）；GSI Helmoltzzentrum für Schwerionenforschung（GSI亥姆霍兹重离子研究中心）；Università di Firenze（佛罗伦萨大学）；INFN Sezione di Firenze（意大利国家核物理研究所佛罗伦萨分部）
In these proceedings, we apply the recently developed S-ACOT-MPS factorization scheme at the next-to-leading order to prompt charm production at hadron colliders. It provides a good agreement with experimental data on charm meson production measured by LHCb at 7 and 13 TeV. The low-$p_T$ data are on the margins of the theoretical error bands, emphasizing the importance of including contributions beyond the next-to-leading order.
The semi-inclusive electroproduction of exotic hadrons, including the $T_{cc}$, $P_{cs}$, and hidden-charm baryon-antibaryon states, is explored under the assumption that they are $S$-wave hadronic molecules of a pair of charmed hadrons. We employ the Monte Carlo event generator Pythia to produce the hadron pairs and then bind them together to form hadronic molecules. With the use of such a production mechanism, the semi-inclusive electroproduction rates are estimated at the order-of-magnitude level. Our results indicate that a larger number of $P_{cs}$ states and $Λ_c\barΛ_c$ molecules can be…
Recent data on the production of $D$ mesons and $Λ_c^+$ baryons in heavy ion collisions at the Relativistic Heavy Ion Collider and the Large Hadron Collider exhibit a number of striking characteristics such as enhanced yield ratios $D_s^+/D^0$, $Λ_c^+/D^0$ and their transverse momentum dependences. In this paper, we derive the momentum dependence of open charm mesons and singly charmed baryons produced in ultra-relativistic heavy ion collisions via the equal-velocity quark combination. We present analytic expressions and numerical results of yield ratios and compare them with the experimental …
Studies of beauty hadron and non-prompt charm hadron production in pp collisions at $\sqrt{s}$=13 TeV within a transport model approach
School of Mathematics and Physics, China University of Geosciences (Wuhan)（中国地质大学（武汉）数学与统计学院）；Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University（华中师范大学夸克与轻子物理教育部重点实验室及粒子物理研究所）；Shanghai Research Center for Theoretical Nuclear Physics, NSFC and Fudan University（复旦大学理论核物理上海研究中心）
We present a new model for the description of heavy-flavor hadronization in high-energy nuclear (and possibly hadronic) collisions, where the process takes place not in the vacuum, but in the presence of other color charges. We explore its effect on the charmed hadron yields and kinematic distributions once the latter is applied at the end of transport calculations used to simulate the propagation of heavy quarks in the deconfined fireball produced in nuclear collisions. The model is based on the formation of color-singlet clusters through the recombination of charm quarks with light antiquark…
