Exotic Quantum States for Charmed Baryons at Finite Temperature

The significantly screened heavy-quark potential in hot medium provides the possibility to study exotic quantum states of three-heavy-quark systems. By solving the Schr\"odinger equation for a three-charm-quark system at finite temperature, we found that, there exist Borromean states which might be realized in high energy nuclear collisions, and the binding energies of the system satisfy precisely the scaling law for Efimov states in the resonance limit

Strong Diffusion Effect of Charm Quarks on J/ψJ/\psi Production in Pb-Pb collisions at the LHC

We study the $J/\psi$ production based on coalescence model at $\sqrt{s_{NN}}$ = 2.76 and 5.02 TeV Pb-Pb collisions. With the colliding energy increasing from 2.76 TeV to 5.02 TeV, the number of charm pairs is enhanced by more than 50%. However, the ratio of $J/\psi$ inclusive nuclear modification factors $R^{5.02TeV}_{AA}/R^{2.76TeV}_{AA}$ is only about 1.1 $\sim$ 1.2. We find that the regeneration of $J/\psi$ is proportional to the densities of charm and anti-charm quarks, instead of their total numbers. The charm quark density is diluted by the strong expansion of quark gluon plasma, which suppresses the combination probability of heavy quarks and $J/\psi$ regeneration. This effect is more important in higher colliding energies where QGP expansion is strong. We also propose the ratio $N_{J/\psi}/(N_D)^2$ as a measurement of $c$ and $\bar c$ coalescence probability, which is only affected by the heavy quark diffusions in QGP, and does not depend on the inputs such as cold nuclear matter effects and cross sections of charm quark production. Further more, we give the predictions at the energy of Future Circular Collider ($\sqrt{s_{NN}}$ = 39 TeV)

Charmonium transport in the high-μB\mu_B medium

We employ the transport model coupled with hydrodynamic equations to study the charmonium dissociation and regeneration in the quark-gluon plasma (QGP) with the large baryon chemical potential in Au-Au collisions at the energies of $\sqrt{s_{NN}}=$ ($39$, $14.5$, $7.7$) GeV. The baryon chemical potential $\mu_B$ is encoded in both Debye mass characterizing the heavy-quark potential and also the equation of state (EoS) of the bulk medium respectively. After considering $\mu_B$-corrections in both heavy quarkonium and the QGP medium, we calculate the nuclear modification factor $R_{AA}$ of charmonium. And find the $\mu_B$ influence on charmonium production at $\sqrt{s_{NN}}$ = 39 and 14.5 GeV is negligible, while the $R_{AA}$ of charmonium is reduced clearly considering $\mu_B$ influence at $\sqrt{s_{NN}}=7.7$ GeV Au-Au collisions. It is crucial for studying charmonium production in low energy and also fixed-target heavy-ion collisions.Comment: 7 pages; 9 figure

Quantum color screening in external magnetic field

We calculate color screening mass in a thermalized and magnetized QCD matter in the frame of loop resummation theory at finite temperature and magnetic field. Different from the normal Debye screening in classical electrodynamics, the color screening mass in an external magnetic field is characterized by the quantized quark transverse energy $\epsilon_n^2=2n|qB|$, similar to the Landau energy levels derived in quantum mechanics. Our calculation without constriction to the temperature and magnetic field strengths comes back to the well-known results in the limits of weak and strong magnetic field.Comment: 9 pages, 1 figur

Investigation of the tetraquark states QqQˉqˉQq\bar{Q} \bar{q} in the improved chromomagnetic interaction model

In the framework of the improved chromomagnetic interaction model, we complete a systematic study of the $S$-wave tetraquark states $Qq\bar{Q}\bar{q}$ ($Q=c,b$, and $q=u,d,s$) with different quantum numbers, $J^{PC}=0^{+(+)}$, $1^{+(\pm)}$, and $2^{+(+)}$. The mass spectra of tetraquark states are predicted and the possible decay channels are analyzed by considering both the angular momentum and $\mathcal{C}$-parity conservation. The recently observed hidden-charm tetraquark states with strangeness, such as $Z_{cs}(3985)^-$, $X(3960)$, and $Z_{cs}(4220)^+$, can be well explained in our model. Besides, based on the wave function of each tetraquark state, we find that the low-lying states of each $Qq\bar{Q}\bar{q}$ configuration have a large overlap to the $Q\bar Q$ and $q\bar q$ meson basis, instead of $Q\bar q$ and $q\bar Q$ meson basis. This indicates one can search these tetraquark states in future experiments via the channel of $Q\bar Q$ and $q\bar q$ mesons.Comment: 11 pages, 9 figures, and 4 tables; accepted for publication in Chinese Physics