标题： 强磁场中的朗道阻尼：夸克偶素的解离 显示英文标题

标题： Landau Damping in a strong magnetic field: Dissociation of Quarkonia

摘要： 我们研究了强磁场对浸在夸克和胶子热介质中的类粲偶素性质的影响，并研究了由于兰道阻尼导致的准自由解离。 在最低兰道能级下对夸克的施温格传播子进行热化，并在实时间形式中对胶子的费曼传播子进行热化，我们计算了重求和的滞后和对称传播子，它们分别给出了介电常数的实部和虚部。 由于磁场对长距离相互作用的影响大于短距离相互作用，因此与没有强磁场的热介质相比，势的实部变得更加吸引，虚部的大小也变得更大。 因此，$J/\psi$和$\psi^\prime$的平均尺寸增加，而$\chi_c$的尺寸则缩小。 同样，磁场对$J/\psi$和$\chi_c$的结合有不同影响，即它减少了$J/\psi$的结合，而增加了$\chi_c$的结合。 然而，磁场的进一步增加会导致结合能的减少。 相反，磁场会增加共振的宽度，除非温度足够高。 最后，我们研究了磁场的存在如何由于兰道阻尼而影响类粲偶素在热介质中的解离，发现解离温度比没有磁场的热介质中的解离温度更高。 然而，磁场的进一步增加会降低解离温度。 例如，$J/\psi$和$\chi_c$在较高温度下在 2$T_c$和 1.1$T_c$在磁场$eB \approx 6~{\rm{and}}~4~m_\pi^2$下分别解离，与无磁场时的值 1.60$T_c$和 0.8$T_c$相比。 显示英文摘要

摘要： We have investigated the effects of strong magnetic field on the properties of quarkonia immersed in a thermal medium of quarks and gluons and studied its quasi-free dissociation due to the Landau-damping. Thermalizing the Schwinger propagator in the lowest Landau levels for quarks and the Feynman propagator for gluons in real-time formalism, we have calculated the resummed retarded and symmetric propagators, which in turn give the real and imaginary components of dielectric permittivity, respectively. The magnetic field affects the large-distance interaction more than the short-distance interaction, as a result, the real part of potential becomes more attractive and the magnitude of imaginary part too becomes larger, compared to the thermal medium in absence of strong magnetic field. As a consequence the average size of $J/\psi$'s and $\psi^\prime$'s are increased but $\chi_c$'s get shrunk. Similarly the magnetic field affects the binding of $J/\psi$'s and $\chi_c$'s discriminately, i.e. it decreases the binding of $J/\psi$ and increases for $\chi_c$. However, the further increase in magnetic field results in the decrease of binding energies. On contrary the magnetic field increases the width of the resonances, unless the temperature is sufficiently high. We have finally studied how the presence of magnetic field affects the dissolution of quarkonia in a thermal medium due to the Landau damping, where the dissociation temperatures are found to increase compared to the thermal medium in absence of magnetic field. However, further increase of magnetic field decreases the dissociation temperatures. For example, $J/\psi$'s and $\chi_c$'s are dissociated at higher temperatures at 2 $T_c$ and 1.1 $T_c$ at a magnetic field $eB \approx 6~{\rm{and}}~4~m_\pi^2$, respectively, compared to the values 1.60 $T_c$ and 0.8 $T_c$ in the absence of magnetic field, respectively.