利用自洽耦合道方法研究了有限温度下核物质中开粲介子（$D$和$\bar {D}$）的性质。介子-重子相互作用采用破缺的SU（4）s波Tomozawa-Weinberg项，并辅以吸引的标量-等腰吸引。在有限温度下的介质中解以自洽的方式包含了泡利阻塞效应、所有重子的平均场束缚、$π$和开魅介子自能。在$DN$部门，$Λ_c$和$Σ_c$共振，动态产生的2593 MeV和2770 MeV的自由空间，保持接近其自由空间的位置，同时获得一个显着的宽度，由于热涂抹泡利阻塞以及从核物质密度的影响。结果，$D$介子谱密度在接近$D$介子自由空间质量的能量处显示出一个明显的峰值，该峰值随着物质密度的增加而变宽，特别是在较低能量处具有延伸的尾部。$\bar D$势表现出适度的排斥行为，来自$\bar D N$相互作用的主导I=1的贡献。然而，低密度定理不是$\bar D$自能的良好近似，尽管在这种情况下没有接近阈值的共振空穴贡献。我们推测了$D$介子核的可能性，并讨论了重离子碰撞中$J/Ψ$抑制的一些结果，特别是对FAIR未来的CBM实验。
英文摘要：
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 MeV and 2770 MeV in free space, remain close to their free-space position while acquiring a remarkable width due to the thermal smearing of Pauli blocking as well as from the nuclear matter density effects. As a result, the $D$ meson spectral density shows a single pronounced peak for energies close to the $D$ meson free-space mass that broadens with increasing matter density with an extended tail particularly towards lower energies. The $\bar D$ potential shows a moderate repulsive behavior coming from the dominant I=1 contribution of the $\bar D N$ interaction. The low-density theorem is, however, not a good approximation for the $\bar D$ self-energy in spite of the absence of resonance-hole contributions close to threshold in this case. We speculate the possibility of $D$-mesic nuclei as well as discuss some consequences for the $J/Ψ$ suppression in heavy-ion collisions, in particular for the future CBM experiment at FAIR.
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 $B…
Nuclear Deformation Effects on Charmonium Suppression in Au+Au and U+U Collisions
Tianjin University（天津大学）；Georgia Institute of Technology（佐治亚理工学院）；Tianjin University-National University of Singapore Joint Institute in Fuzhou（福州中新联合研究院）
The in-medium masses of the open charm ($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 (…
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 study the partial decay widths of the charmonium states ($J/ψ$, $ψ(3686)$, $ψ(3770)$, $χ_{c0}$, $χ_{c2}$) to $D\bar D$ ($D^+D^-$ or $D^0\bar {D^0}$) in isospin asymmetric nuclear matter, in the presence of strong magnetic fields. The in-medium partial decay widths of charmonium states to $D\bar D$ are calculated within a light quark--antiquark pair creation model, namely the $^3P_0$ model, using the in--medium masses of the charmonia as well as $D$ and $\bar D$ mesons in the magnetized nuclear matter obtained within a chiral effective model. The presence of a magnetic field leads to Landau …
In-medium properties of the low-lying strange, charm, and bottom baryons in symmetric nuclear matter are studied in the quark-meson coupling (QMC) model. Results for the Lorentz-scalar effective masses, mean field potentials felt by the light quarks in the baryons, in-medium bag radii, and the lowest mode bag eigenvalues are presented for those calculated using the updated data. This study completes the in-medium properties of the low-lying baryons in symmetric nuclear matter in the QMC model, for the strange, charm and bottom baryons which contain one or two strange, one charm or one bottom q…
We investigate the in-medium masses of open charm mesons ($D$($D^0$, $D^+$), $\bar{D}$($\bar{D^0}$, $D^-$), $D_s$(${D_{s}}^+$, ${D_{s}}^-$)) and charmonium states ($J/ψ$, $ψ(3686)$, $ψ(3770)$, $χ_{c0}$, $χ_{c2}$) in strongly magnetized isospin asymmetric strange hadronic matter using a chiral effective model. In the presence of the magnetic field, the number density and scalar density of charged baryons have contributions from Landau energy levels. The mass modifications of open charm mesons arise due to their interactions with nucleons, hyperons, and the scalar fields (the non-strange field $…
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 decay widths of the charmonium states to $D\bar D$ in isospin asymmetric nuclear matter in the presence of a magnetic field are studied, using a field theoretical model for composite hadrons with quark/antiquark constituents. The medium modifications of these partial decay widths arise due to the changes in the masses of the decaying charmonium state and the produced $D$ and $\bar D$ mesons in the magnetized hadronic matter, calculated within a chiral effective model. The decay widths are computed using the light quark--antiquark pair creation term of the free Dirac Hamiltonian in terms of…
Recent results for the $η_c$- and $J/ψ$-nucleus bound state energies for various nuclei are presented. The attractive potentials for the $η_c$ and $J/ψ$ mesons in the nuclear medium originate, respectively, from the in-medium enhanced $DD^{*}$ and $D\bar{D}$ loops in the $η_c$ and $J/ψ$ self energies. Our results suggest that the $η_c$ and $J/ψ$ mesons should form bound states with all the nuclei considered.
