We present the first predictions for sub-threshold open charm and charmonium production in nuclear collisions. The production mechanism is driven by multi-step scatterings of nucleons and their resonance states, accumulating sufficient energy for the production of $J/Ψ$, $Λ_c + \overline{D}$ and $D+\overline{D}$. Our results are of particular importance for the CBM experiment at FAIR, as they indicate that already at the SIS100 accelerator one can expect a significant number of charmed hadrons to be produced. This opens new possibilities to explore charm dynamics and the formation of charmed nuclei.
We study charmonium production in hadron-nucleus collisions through the intermediate next-to-leading Fock space component $|(\bar{c}c)_8 g>$, formed by a colour octet $\bar{c}c$ pair and a gluon. We estimate the size of this state and show that its interaction with nucleons accounts for the observed charmonium suppression in nuclear interactions.
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.
We study the properties of the scalar charm resonances $D_{s0}(2317)$ and $D_0(2400)$, and the theoretical hidden charm state X(3700) in nuclear matter. We find that for the $D_{s0}(2317)$ and X(3700) resonances, with negligible and small width at zero density, respectively, the width becomes about $100 {\rm MeV}$ and $200 {\rm MeV}$ at normal nuclear matter density, accordingly. For $D_0(2400)$ the change in width is relatively less important. We discuss the origin of this new width and trace it to reactions occurring in the nucleus. We also propose a possible experimental test for those modi…
I discuss the diffractive production of charmonium from nuclei and the anomalous nuclear attenuation --- termed ``color transparency'' --- attributed to such processes, focusing on the few tens of GeV energy regime germane to the ELFE project. A critical review of color transparency calculations is presented, and the major sources of uncertainty are emphasized.
We calculate, for the first time, $J/ψ$ triangular flow in high energy nuclear collisions. The charmonium motion in medium is controlled by a transport equation with loss and gain terms, and the evolution of the hot medium is governed by a single-shot hydrodynamic equation with a triangularly deformed initial condition. In comparison with the elliptic flow $v_2$, the triangular flow $v_3$ comes almost completely from the charmonium regeneration in the quark gluon plasma and therefore is more sensitive to the medium properties.
We calculate and resum the nuclear enhanced power corrections from the final state partonic scattering in nuclear matter to open charm production and correlations. In p+A reactions, we find that single and double inclusive D mesons can be suppressed as much as the neutral pions from the dynamical high twist shadowing. Effects of initial state energy loss in p+A collisions are also investigated and may lead to significantly weaker transverse momentum dependence of the nuclear suppression.
Measurements of $ψ$ and $ψ'$ production from experiment NA50 at the CERN SPS are compared to predictions based on a hadronic model of charmonium suppression by Vogt and myself. Data on centrality dependence and total cross sections are in good accord with our predictions. Uncertainties in theoretical quanities such as NA50's $L$ parameter are discussed.
We calculate the nucleon and nuclear photoproduction cross sections for heavy quarks within the $k_{\perp}$-factorization formalism, considering the current high energy approaches which include nuclear and saturation effects. Our results demonstrate that a future experimental analysis of this process would allow to constraint the QCD dynamics at high energies.
It is important to understand the strong external magnetic field generated at the very beginning of high energy nuclear collisions. We study the effect of the magnetic field on the charmonium yield and anisotropic distribution in Pb+Pb collisions at the LHC energy. The time dependent Schrödinger equation is employed to describe the motion of $c\bar{c}$ pairs. We compare our model prediction of non- collective anisotropic parameter $v_2$ of $J/ψ$s with CMS data at high transverse momentum. This is the first attempt to measure the magnetic field in high energy nuclear collisions.
We consider heavy mesons with charm and bottom in nuclear medium. We construct the effective Lagrangian with axial-vector coupling including 1/M-corrections for the heavy meson mass $M$ by following the velocity-rearrangement invariance. As an application, we consider heavy mesons, $\bar{\mathrm{D}}$ and $\bar{\mathrm{D}}^{\ast}$ mesons for charm and $\mathrm{B}$ and $\mathrm{B}^{\ast}$ mesons for bottom, bound in nuclear matter, and we discuss their in-medium masses modified by the interaction with nucleons via pion exchanges including the 1/M-corrections. The mass modifications are affected …
Data from J/psi and psi' production in p-A collisions are used to determine the cross section for absorption of pre-resonance charmonium in nuclear matter. The J/psi suppression in O-Cu, O-U and S-U collisions is fully reproduced by the corresponding nuclear absorption, while Pb-Pb collisions show an additional suppression increasing with centrality. We study the onset of this change in terms of hadronic comover interactions and conclude that so far no conventional hadronic description can consistently account for all data. Deconfinement, starting at a critical point determined by central S-U …
We study the evolution of charmonia as they collide with the constituents of the fireball produced in high-energy nucleus-nucleus collisions. The latter evolves in a manner controlled by the equation of state as given by lattice QCD, and is constructed in such a way that the observed hadronic spectra are correctly reproduced. A kinetic description of charmonium interactions with both quark-gluon and hadronic degrees of freedom allows to study in detail the evolution in different regimes, controlled by collision energy, kinematics and geometry. The data collected at the CERN-SPS accelerator are…
We study the centrality dependence to be expected if only charmonium production in the corona survives in high energy nuclear collisions, with full suppression in the hot, deconfined core. To eliminate cold nuclear matter effects as far as possible, we consider the ratio of charmonium to open charm production. The centrality dependence of this ratio is found to follow a universal geometric form, applicable to both RHIC and LHC in collisions at central and forward rapidities.
Cross sections for the charm-production reactions $\bar p p \to \bar Λ_c^- Σ_c^+$, $\bar Σ_cΣ_c$, $\bar Ξ_cΞ_c$, and $\bar Ξ_c'Ξ_c'$ are presented, for energies near their respective thresholds. The results are based on a calculation performed in the meson-exchange framework in close analogy to earlier studies of the Jülich group on the strangeness-production reactions $\bar p p \to \bar ΛΣ$, $\bar ΣΣ$, $\bar ΞΞ$ by connecting the two sectors via SU(4) flavor symmetry. The cross sections are found to be in the order of $0.1 - 1$ $μb$ at energies of $100$ MeV above the respective thresholds, fo…
In the energy range of RHIC and LHC the mechanisms of nuclear suppression of charmonia are expected to be strikingly different from what is known for the energy of the SPS. One cannot think any more of charmonium produced on a bound nucleon which then attenuates as it passes through the rest of the nucleus. The coherence length of charmonium production substantially exceeds the nuclear radius in the new energy range. Therefore the production amplitudes on different nucleons, rather than the cross sections, add up and interfere, i.e. shadowing is at work. So far no theoretical tool has been ava…
We discuss the interaction of an open heavy meson ($\bar{D}$ and $\bar{D}^{\ast}$ for charm or $B$ and $B^{\ast}$ for bottom) and a nucleon ($N$) by considering the $π$, $σ$, $ρ$, and $ω$ exchange potentials. We construct a potential model by respecting chiral symmetry for light quarks and spin symmetry for heavy quarks. Model parameters are adjusted by referring the phenomenological nuclear (CD-Bonn) potentials reproducing the low-energy $NN$ scatterings. We show that the resulting interaction may accommodate $\bar{D}N$ and $BN$ bound states with quantum number $I(J^{P})=0(1/2^{-})$, and a $B…
In high energy nuclear collisions, the Glauber model is commonly used to evaluate $J/ψ$ suppression due to inelastic interaction with colorless bound nucleons. This requires an effective value for the $J/ψ$-nucleon absorption cross section which is larger than theoretically expected. On the other hand, multiple nucleon-nucleon collisions mediated by color exchange interactions, excite their color degrees of freedom. We investigate the importance of this effect and conclude that the related corrections are important to explain the effective value extrapolated from experiment.
Nuclear Deformation Effects on Charmonium Suppression in Au+Au and U+U Collisions
Tianjin University（天津大学）；Georgia Institute of Technology（佐治亚理工学院）；Tianjin University-National University of Singapore Joint Institute in Fuzhou（福州中新联合研究院）
Employing QCD sum rules the in-medium modifications of scalar charm mesons in a cold nuclear matter environment are estimated. The mass splitting of D*-D*-bar is quantified.
I discuss issues related to charmonium production, in view of physics possibilities at a 15 ... 30 GeV continuous beam electron facility. High energy photo- and hadroproduction of heavy quarkonia presents several challenges to QCD models concerning cross sections, polarization and nuclear target dependence. Theoretical approaches based on color evaporation as well as on color singlet and color octet mechanisms have met with both successes and failures, indicating that charmonium production is a sensitive probe of color dynamics. Experiments close to charm kinematic threshold will be sensitive …
We obtain the properties of charmed mesons in dense matter using a coupled-channel approach which accounts for Pauli blocking effects and meson self-energies in a self-consistent manner. We study the behaviour of dynamically-generated baryonic resonances together with the open-charm meson spectral functions in this dense nuclear environment. We discuss the implications of the in-medium properties of open-charm mesons on the $D_{s0}(2317)$ and the predicted X(3700) scalar resonances, and on the formation of $D$-mesic nuclei.
The Charmonium transverse momentum distribution is more sensitive to the nature of the hot QCD matter created in high energy nuclear collisions, in comparison with the yield. Taking a detailed transport approach for charmonium motion together with a hydrodynamic description for the medium evolution, the cancelation between the two hot nuclear matter effects, the dissociation and the regeneration, controls the charmonium transverse momentum distribution. Especially, the second moment of the distribution can be used to differentiate between the hot mediums produced at SPS, RHIC and LHC energies.
We study the renormalization of the properties of low lying charm and hidden charm scalar mesons in a nuclear medium, concretely of the D_{s0}(2317) and the theoretical hidden charm state X(3700). We find that for the D_{s0}(2317), with negligible width at zero density, the width becomes about 100 MeV at normal nuclear matter density, while in the case of the X(3700) the width becomes as large as 200 MeV. We discuss the origin of this new width and trace it to reactions occurring in the nucleus, while offering a guideline for future experiments testing these changes. We also show how those med…
Changes in properties of heavy hadrons with a charm or a bottom quark are studied in nuclear matter. Effective masses (scalar potentials) for the hadrons are calculated using quark-meson coupling model. Our results also suggest that the heavy baryons containing a charm or a bottom quark will form charmed or bottom hypernuclei, which was first predicted in mid 70's. In addition a possibility of $B^-$-nuclear bound (atomic) states is briefly discussed.
The in-medium masses of the open charm ($D$ and $\bar D$) mesons in magnetized isospin asymmetric nuclear matter are investigated within a chiral effective model, including the contributions of the Dirac sea (DS) to the self-energies of the nucleons. Within the model, the masses of these mesons are calculated from their interactions with the nucleons and the scalar ($σ\sim(\langle\bar u u\rangle+\langle \bar d d \rangle)$, $ζ\sim\langle {\bar s}s\rangle$ and $δ\sim(\langle{\bar u} u\rangle-\langle {\bar d} d\rangle)$) fields. The Dirac sea contributions are observed to lead to an enhancement (…
The existence of the $X(3872)$ resonance extremely close to the $D^{*0} \bar{D}^0$ threshold implies that neutral charm mesons have an approximate nonrelativistic conformal symmetry. Systems consisting of these mesons with small kinetic energies produced in a short-distance reaction are unparticles in the sense that they can be created by operators with definite scaling dimensions in a nonrelativistic conformal field theory. There is a scaling region in which their energy distribution has power-law behavior with an exponent determined by the scaling dimension of the operator. The unparticle as…
We study the properties of charmed hadrons in dense matter within a coupled-channel approach which accounts for Pauli blocking effects and meson self-energies in a self-consistent manner. We analyze the behaviour in this dense environment of dynamically-generated baryonic resonances as well as the open-charm meson spectral functions. We discuss the implications of the in-medium properties of open-charm mesons on the $D_{s0}(2317)$ and the predicted X(3700) scalar resonances.
I discuss the properties of the $Λ_{c}$ baryon in nuclear matter at zero or finite temperature. Starting from the Lagrangian based on the heavy-quark effective theory, I derive the effective Lagrangian for the $Λ_{c}$ baryon existing as an impurity particle. Adopting the one-loop calculation for nucleons, I derive the effective potential as the quantity for measuring the stability of the $Λ_{c}$ baryon in nuclear matter. The parameters in the Lagrangian are fitted to reproduce the scattering length of the nucleon and the $Λ_{c}$ baryon estimated in the lattice QCD simulations and the chiral ex…
We provide predictions for charmonium and open charm production in nuclear collisions at SPS/FAIR energies within the framework of the statistical hadronization model. The increasing importance at lower energies of Lambda_c production is demonstrated and provides a challenge for future experiments. We also demonstrate that, because of the large charm quark mass and the different timescales for charm quark and charmed hadron production, possible modifications of charmed hadrons in the hot hadronic medium do not lead to measurable changes in cross sections for D-meson production. A possible infl…
We discuss the production of charmonium states in antiproton-nucleus collisions at the $ψ'$ threshold. It is explained that measurements in $\bar p A$ collisions will allow to get new information about the strengths of the inelastic $J/ψN, ψ'N$ interaction, on the production of $Λ_c$ and $\bar{D}$ in charmonium-nucleon interactions and for the first time about nondiagonal transitions $ψ' N\to J/ψN$. The inelastic $J/ψ$-nucleon cross section is extracted from the comparison of hadron-nucleus collisions with hadron-nucleon collisions. We extract the total $J/ψ$ nucleon cross section from photon-…
We study hadronic molecules formed by a heavy meson and a nucleon, DN and D*N (BbarN and Bbar*N) systems. Respecting the heavy quark symmetry and chiral symmetry, we consider the DN-D*N (BbarN-Bbar*N$) mixing induced by the one boson exchange potential including the tensor force. We find many bound and resonant states with J^P=1/2^\pm, 3/2^\pm, 5/2^\pm and 7/2^- in isospin singlet channels, while only a few resonant states with J^P=1/2^- in isospin triplet channels. The analysis of DN and D*N (BbarN and Bbar*N) molecules will be useful to study mass spectra of excited charmed (bottom) baryons …
Physics of charmonium suppression in nuclear collisions drastically changes between the energies of SPS and RHIC. Mechanisms suppressing charmonia at SPS are reviewed, neither of which is important at RHIC. On the other hand, coherence, or shadowing of c-quarks and gluons barely seen at SPS, become a dominant effect at RHIC providing a much stronger suppression. A onset of coherence at Fermilab energies explains the observed cross section ratio steeply falling at large Feynman x_F. In nuclear collisions variation of charmonium suppression with x_F suggests a sensitive probe for QGP.
The Compressed Baryonic Matter (CBM) experiment at the Facility for Anti-proton and Ion Research (FAIR) will provide new possibilities for charm-quark ($D$-meson) observables in heavy-ion collisions at low collision energies and high baryon densities. To predict the collective flow and nuclear modification factors of charm quarks in this environment, we apply a Langevin approach for the transport of charm quarks in the UrQMD (hydrodynamics + Boltzmann) hybrid model. Due to the inclusion of event-by-event fluctuations and a full (3+1) dimensional hydrodynamical evolution, the UrQMD hybrid appro…
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…
We discuss the new data for the production of the $ψ'$ meson in pA collisions at 450 GeV at CERN-SPS (of the NA50-collaboration) [1]. We extract from the CERN data $σ(ψ' N)\approx 8$ mb under the assumption that the $ψ'$ is produced as a result of the space-time evolution of a point-like $c\bar c$ pair which expands with time to the full size of the charmonium state. In the analysis we assume the existence of a relationship between the distribution of color in a hadron and the cross section of its interaction with a nucleon. However, our result is rather sensitive to the pattern of the expansi…
We study the nuclear medium effects on the $c\bar{c}$ time evolution and charmonium production, in a relativistic proton-nucleus collision. In particular, we focus on the fragmentation region of the nucleus where the formation length of the charmonium mesons is shorter than the size of the nucleus. Little is known on the nuclear effects in this region. We use a quantum-mechanical model which includes a realistic potential for the $c\bar{c}$ system and an imaginary potential to describe the collisions of the $c\bar{c}$ with the nucleons. The imaginary potential introduces a transition amplitude…
The pre-equilibrium contribution to open charm production in nuclear collisions at $\sqrt{s}=200$ AGeV is calculated using three different models for the correlations between momentum and space-time coordinates. Ideal (Bjorken) correlation between the rapidity $y$ and space-time rapidity $η$ of mini-jet gluons suppresses greatly the pre-equilibrium yield and even allowing for the minimal uncertainty correlations leads, in contrast to previous estimates, only to a small pre-equilibrium charm yield as compared to initial yield due to gluon fusion. The ``intrinsic'' charm process is negligible in…
Opposite-sign lepton pairs ($ee$,$eμ$ and $μμ$) from open charm decay are proposed as a measure of nuclear shadowing effects. Via an approximate scaling the ratio of the dilepton spectra from $p+A$ to those from $pp$ reflects the shadowing function well. We show that the required measurements are feasible at the Relativistic Heavy ion Collider (RHIC) by considering the backgrounds according to the proposed PHENIX detector geometry.
We study the properties of open-charm mesons ($D$ and $\bar {D}$) in nuclear matter at finite temperature within a self-consistent coupled-channel approach. The meson-baryon interactions are adopted from a type of broken SU(4) s-wave Tomozawa-Weinberg terms supplemented by an attractive scalar-isoscalar attraction. The in-medium solution at finite temperature incorporates Pauli blocking effects, mean-field binding on all the baryons involved, and $π$ and open-charm meson self-energies in a self-consistent manner. In the $DN$ sector, the $Λ_c$ and $Σ_c$ resonances, generated dynamically at 2593…
We study the effect of thermal charm production on charmonium regeneration in high energy nuclear collisions. By solving the kinetic equations for charm quark and charmonium distributions in Pb+Pb collisions, we calculate the global and differential nuclear modification factors $R_{AA}(N_{part})$ and $R{AA}(p_t)$ for $J/Ψ$s. Due to the thermal charm production in hot medium, the charmonium production source changes from the initially created charm quarks at SPS, RHIC and LHC to the thermally produced charm quarks at Future Circular Collider (FCC), and the $J/Ψ$ suppression ($R_{AA}<1$) observe…
In high-energy nuclear collisions, heavy quark potential at finite temperature controls the quarkonium production. Including the relaxation of the medium induced by the relative velocity between quarkonia and the deconfined expanding matter, the Debye screening is reduced and the quarkonium dissociation takes place at a higher temperature. As a consequence of the velocity dependent dissociation temperature, the quarkonium suppression at high transverse momentum is significantly weakened in high energy nuclear collisions at RHIC and LHC.
The properties of open charm mesons, $D$, $\bar D$, $D_s$ and $\bar D_s$ in nuclear matter at finite temperature are studied within a self-consistent coupled-channel approach. The interaction of the low lying pseudoscalar mesons with the ground state baryons in the charm sector is derived from a $t$-channel vector-exchange model. The in-medium scattering amplitudes are obtained by solving the Lippmann-Schwinger equation at finite temperature including Pauli blocking effects, as well as $D$, $\bar D$, $D_s$ and $\bar D_s$ self-energies taking their mutual influence into account. We find that th…
We investigate the structure and formation of charmed meson--nucleus systems, with the aim of understanding the charmed meson--nucleon interactions and the properties of the charmed mesons in the nuclear medium. The $\bar{D}$ mesic nuclei are of special interest, since they have tiny decay widths due to the absence of strong decays for the $\bar{D} N$ pair. Employing an effective model for the $\bar{D} N$ and $D N$ interactions and solving the Klein--Gordon equation for $\bar{D}$ and $D$ in finite nuclei, we find that the $D^{-}$-${}^{11}\rm{B}$ system has $1 s$ and $2p$ mesic nuclear states a…
We investigate charmonium production in Pb+Pb collisions at LHC beam energy $E_{\text {lab}}$=2.76 A TeV at fixed-target experiment ($\sqrt {s_{\text{NN}}}$=72 GeV). In the frame of a transport approach including cold and hot nuclear matter effects on charmonium evolution, we focus on the anti-shadowing effect on the nuclear modification factors $R_{AA}$ and $r_{AA}$ for the $J/ψ$ yield and transverse momentum. The yield is more suppressed at less forward rapidity ($y_\text{lab}\simeq$2) than that at very forward rapidity ($y_\text{lab}\simeq$4) due to the shadowing and anti-shadowing in diffe…
Density dependences of the mass and self-energies of $Λ_c$ in nulear matter are studied in the parity projected QCD sum rule. Effects of nuclear matter are taken into account through the quark and gluon condensates. It is found that the four-quark condensates give dominant contributions. As the density dependences of the four-quark condensates are not known well, we examine two hypotheses. One is based on the factorization hypothesis (F-type) and the other is derived from the perturbative chiral quark model (QM-type). The F-type strongly depends on density, while the QM-type gives a weaker dep…
We present results for the $η_c$-nucleus bound state energies for various nuclei using an effective Lagrangians approach. The attractive potentials for the $η_c$ in the nuclear medium originate from the medium-modified intermediate $D D^{*}$ state in the $η_c$ self energy, using the local density approximation. Our results suggest that the $η_c$ should form bound states with all the nuclei considered
The strong interaction between heavy quarks and the quark gluon plasma makes the open and hidden charm hadrons be sensitive probes of the deconfinement phase transition in high energy nuclear collisions. Both the cold and hot nuclear matter effects change with the colliding energy and significantly influence the heavy quark and charmonium yield and their transverse momentum distributions. The ratio of averaged quarkonium transverse momentum square and the elliptic flow reveal the nature of the QCD medium created in heavy ion collisions at SPS, RHIC and LHC energies.
We present results on rapidity and transverse momentum distributions of inclusive charm quark production in heavy-ion collisions at RHIC, including the next-to-leading order, $O(α_s^3)$, radiative corrections and the nuclear shadowing effect. We find the effective, nuclear K-factor to be $K(y)\approx 1.4$ for $\mid y\mid \leq 3$ in the rapidity distribution, while $1\leq K(p_{T}) \leq 3$ for $1GeV\leq p_T \leq 6GeV$ in the $p_T$ distribution. We incorporate multiple parton scatterings in our calculation of the fraction of all central events that contain at least one charm quark pair. We obtain…
The associative charm particles production in nucleon-nucleon collisions $N+N\to Λ_c(Σ_c)+\bar{D}+N$, is described in a general way and the spin and isospin structure of the corresponding matrix elements are derived. Using an analogy with strange particle ($ΛK$)-production, the $D-$meson exchange model is considered in detail. Estimations of the energy behavior of the threshold cross sections show a large dependence on the form of the phenomenological hadron form factors and indicate that, at threshold, the cross section is three order of magnitude smaller than for strange particle production.
Nuclei are transparent for a heavy intrinsic charm (IC) component of the beam hadrons, what leads to an enhanced nuclear dependence of open charm production at large Feynman x_F. Indeed, such an effect was observed recently in the SELEX experiment. Our calculations reproduce well the data, providing strong support for the presence of IC in hadrons in amount less than 1%. Moreover, we performed an analysis of nuclear effects in J/Psi production and found a similar, although weaker effect
We study the spectral distributions of charmed meson with $J^P=0^-$ quantum numbers in cold nuclear matter applying a self-consistent and covariant many-body approach established previously for the nuclear dynamics of kaons. At leading orders the computation requires as input the free-space two-body scattering amplitudes only. Our results are based on the s-wave meson-nucleon amplitudes obtained recently in terms of a coupled-channel approach. The amplitudes are characterized by the presence of many resonances in part so far not observed. This gives rise to an intriguing dynamics of charmed me…
Open charm production at the initial and the pre-equilibrium stages in nuclear collisions is studied. The pre-equilibrium contribution to open charm production in $A+A$ collisions at $\sqrt s=200 AGeV$ is shown to be very sensitive to correlations between momenta and space-time coordinates of the minijets produced after the initial collision. A minimal correlation model based on the uncertainty principle is introduced, and leads only to a small pre-equilibrium charm yield as compared with initial yields. Opposite-sign lepton pairs $ee, eμ$ and $μμ$ from open charm decay in $p+A$ reactions at $…
We investigate the transition from suppression to enhancement of J/psi mesons produced in ultra-relativistic nuclear collisions in the framework of the statistical hadronization model. The calculations are confronted with the most recent data from the RHIC accelerator. This comparison yields first direct evidence for generation of J/psi mesons at the phase boundary. Based on the success of this approach we make specific predictions for LHC energy.
We make up-to-date QCD predictions for open charm and bottom production at RHIC in nucleon-nucleon collisions at \sqrt{S} = 200 GeV. We also calculate the electron spectrum resulting from heavy flavor decays to allow direct comparison to the data. A rigorous benchmark, including the theoretical uncertainties, is established against which nuclear collision data can be compared to obtain evidence for nuclear effects.
Multi-strange and charmed hadrons: A novel probe for the QCD equation of state at high baryon densities
GSI Helmholtzzentrum für Schwerionenforschung GmbH（吉赛亥尔霍兹重离子研究中心有限公司）；Frankfurt Institute for Advanced Studies（法兰克福高等研究所）；Institut für Theoretische Physik, Goethe-Universität Frankfurt（歌德大学法兰克福理论物理研究所）；Helmholtz Research Academy Hesse for FAIR (HFHF)（黑森亥尔霍兹FAIR研究学院）
