Recent experiments have found spin alignment of $J/ψ$ with respect to event plane in heavy ion collisions, suggesting a medium effect that is spin dependent. We propose a possible mechanism with polarized dissociation from the motion of $J/ψ$ with respect to the medium. We calculate polarized dissociation rate for quarkonium spin triplet state from spin chromomagnetic coupling in the potential non-relativistic QCD framework. This is done for the leading order gluo-dissociation process and next to leading order inelastic Coulomb scattering process. The polarized dissociation rate is expressed as a function of relative velocity between quarkonium and QGP and the quantization axis. Applying the polarized dissociation rate to quarkonium evolution with dissociation effect only in a Bjorken flow, we find the spin $0$ state to dissociate less than the other spin states, leading to positive $ρ_{00}-1/3$. Regeneration contribution is expected to give a contribution with the opposite sign.
The real-time dissociation of the heavy quarkonium in a strongly coupled boost-invariant non-Abelian plasma relaxing towards equilibrium is analyzed in a holographic framework. The effects driving the plasma out of equilibrium are described by boundary quenching, impulsive variations of the boundary metric. Quarkonium is represented by a classical string with endpoints kept close to the boundary. The evolution of the string profile is computed in the time-dependent geometry, and the dissociation time is evaluated for different configurations with respect to the direction of the plasma expansio…
For weakly bound quarkonia, we rederive the next-to-leading order cross sections of quarkonium dissociation by partons that include the hard thermal loop (HTL) resummation. Our results calculated with an effective vertex from the Bethe-Salpeter amplitude reduce to those obtained by potential nonrelativistic QCD (pNRQCD) in the relevant kinematical limit, and they can be used in a wide temperature range applicable to heavy quark systems in heavy ion collisions. Based on the lattice computation of the temperature-dependent binding energy, our numerical analysis on $Υ(1S)$ indicates that at high …
We consider the quarkonium diffusion, dissociation and recombination inside quark-gluon plasma. We compute scattering amplitudes in potential nonrelativistic QCD for relevant processes. These processes include the gluon absorption/emission at the order $gr$, inelastic scattering at the order $g^2r$ and elastic scattering with medium constituents at the order $g^2r^2$. We show these amplitudes satisfy the Ward identity. We also consider one-loop corrections. The dipole interaction between the color singlet and octet is not running at the one-loop level. Interference between the tree-level gluon…
The probability of tunnel decay of quarkonium (bond state of a heavy quark and a heavy antiquark) into free quarks in a strong electric field is estimated.
Medium-Induced Quarkonium Dissociation at Finite Chemical Potential and Weak Magnetic Field
Discipline of Natural Sciences, PDPM IIITDM（PDPM印度理工学院德里曼德拉技术学院自然学系）；Department of Physics, Lords Institute of Engineering and Technology（洛兹工程技术学院物理系）；Key Laboratory of Quark and Lepton Physics (MOE) & 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）；Department of Physics, Integral University（Integral大学物理系）；Department of Physics, Institute of Science, Banaras Hindu University (BHU)（贝拿勒斯印度教大学科学研究所物理系）
Using an effective Hamiltonian derived from the QCD multipole expansion, we calculate the cross sections of gluo-dissociation of heavy quarkonia in the quark-gluon plasma, by including both the chromo-electric dipole ($E_1$) as well as the chromo-magnetic dipole ($M_1$) transition mechanisms. While the former allows to reproduce the results from operator-product-expansion calculations in the Coulomb approximation, the latter as a novel contribution is shown to be significant at low energies close to the threshold. Using thus obtained cross sections, we further carry out a full calculation of t…
Using the chromo-electric dipole coupling Hamiltonian from QCD multipole expansion, we derive the dissociation cross sections of heavy quarkonia by thermal gluons at next-to-leading order (NLO, also known as inelastic parton scattering dissociation) in the Quark-Gluon Plasma (QGP) in the framework of second order quantum mechanical perturbation theory. While suffering divergence (infrared and soft-collinear divergences) in vacuum, the cross sections thus derived become finite in the QGP as rendered by the finite thermal gluon masses. In contrast to the leading order (LO, also known as gluo-dis…
Holographic entropy and real-time dynamics of quarkonium dissociation in non-Abelian plasma
在格点量子色动力学中观察到的解除禁闭跃迁处的重夸克对熵峰值表明，该跃迁是由束缚态熵的增加有效驱动的。熵随夸克间距的增大而增大，导致熵力的突现，引起夸克偶素态的离解。由于跃迁点附近的夸克-胶子等离子体是一个强耦合系统，我们利用规范-引力对偶性研究了重夸克偶素的熵及其离解的实时动力学。特别地，我们采用改进的全息QCD模型作为大$N_c$ Yang Mills理论的对偶描述。研究边界上夸克之间的基本弦的动力学，我们发现熵在跃迁点处达到峰值。我们还研究了系统的实时动力学，考虑全息字符串下降的黑洞视界，它平衡。在附近的解除禁闭过渡，解离时间被发现是小于费米，这表明熵破坏是在这个温度区域的主要解离机制。
We investigate the real-time evolution of quarkonium bound states in a quark-gluon plasma in one dimension using an improved QCD based stochastic potential model. This model describes the quarkonium dynamics in terms of a Schrödinger equation with an in-medium potential and two noise terms encoding the residual interactions between the heavy quarks and the medium. The probabilities of bound states in a static medium and in a boost-invariantly expanding quark-gluon plasma are discussed. We draw two conclusions from our results: One is that the outcome of the stochastic potential model is qualit…
In this paper, quarkonium dissociation is investigated in an anisotropic plasma in the hot and dense media. For that purpose, the multidimensional Schrodinger equation is solved analytically by Nikiforov-Uvarov (NU) method for the real part of the potential in an anisotropic medium. The binding energy and dissociation temperature are calculated. In comparison with an isotropic medium, the binding energy of quarkonium is enhanced in the presence of an anisotropic medium. The present results show that the dissociation temperature increases with increasing anisotropic parameter for 1S state of th…
The analytical exact iteration method (AEIM) have been used to calculate the N-dimensional radial schrodinger equation with the real part of complex-valued potential and it is generalized to the finite value of anisotropy (ξ), temperature and baryonic chemical potential. In N-dimensional space the energy eigen values have been calculated for any states (n,l). The present results have been used to study the properties of quarkonium states (i.e, the binding energy and mass spectra in the N-dimensional space). The influences of anisotropy (ξ) on the dissociation temperature(TD) has been also calc…
We calculate the transition between a quarkonium state and an unbound heavy quark-antiquark pair through gluo-dissociation and inelastic parton scattering using a partonic picture that interpolates between the formal limits based on potential nonrelativistic QCD (pNRQCD) at different temperatures. While the thermal width increases with momentum and temperature, the quarkonium regeneration is affected by the heavy quark distribution function which depends on the diffusion constant. By solving the Boltzmann equation with the dissociation and regeneration terms, we investigate the medium modifica…
By coupling the Boltzmann transport equations of both quarkonium and open heavy quarks, we investigate their dynamical evolution inside the quark-gluon plasma and study quarkonium production in heavy ion collisions. The Boltzmann transport equation of quarkonium is derived from the open quantum system formalism and effective field theory of QCD by assuming quarkonium interacts weakly with the plasma. The dissociation and recombination terms in the Boltzmann equation are calculated in potential nonrelativistic QCD. It is shown that the combination of quarkonium dissociation, recombination, open…
Heavy Quarkonium in a weakly-coupled quark-gluon plasma below the melting temperature
我们计算了一个夸克-胶子等离子体中的重夸克偶素能级和衰变宽度，该等离子体的温度T和屏蔽质量m_D满足m α_s >> T >> m α_s^2>> m_D（m是重夸克质量），m α_s^5阶。我们首先顺序地积分出尺度m、m α_s和T，然后，我们使用区域积分技术在所得到的有效理论中进行计算。确定了一个共线区域，该区域以该顺序起作用。我们还讨论了我们的结果对重离子碰撞中重夸克偶素抑制的影响。
We derive equations of motion for the reduced density matrix of a heavy quarkonium in contact with a quark-gluon plasma in thermal equilibrium. These equations allow in particular a proper treatment of the regime when the temperature of the plasma is comparable to the binding energy of the quarkonium. These equations are used to study how the quarkonium approaches equilibrium with the plasma, and we discuss the corresponding entropy increase, or free energy decrease, depending on the temperature regime. The effect of collisions can be accounted for by the generalization of the imaginary potent…
We study the properties of the Lindbladian quantum mechanical evolution of quarkonia with non-Abelian charges (color-singlet and octet) in the quark-gluon plasma. We confirm that heavy quark recoils in the Lindblad equation correctly thermalize quarkonium colorful states within statistical errors from the simulation method. We also demonstrate that the Lindblad equation in the dipole limit can provide an efficient alternative method, which is applicable to a finite time evolution before thermalization and dramatically reduces the numerical cost. Our findings will serve as a foundation for larg…
