Speaker
Summary
Heavy quarks have been used as probes to study the properties of Quark-Gluon Plasma (QGP). Because the mass of heavy quarks is much larger than the typical temperature of QGP produced in current experiments of relativistic heavy ion collisions, the production of heavy quarks is thought to be largely limited to the early stages of the collisions, i.e. the early “hard” processes. The number of charm quark and anti-charm quark (ccbar) pairs produced in these hard processes is much larger than that required by chemical equilibrium; therefore the ccbar pairs tend to annihilate towards chemical equilibrium. When their relative momentum is not very large, the ccbar in color singlet state will form a bound state because of the attractive interaction, which is to reduce the energy of the ccbar system. As a result, the probability of annihilation is increased, commonly known as Sommerfeld enhancement. In this work[1], we propose a annihilation process involving non-perturbative scattering. We use non-relativistic quantum mechanics Lippmann -Schwinger equation (LSE) to derive the scattering matrix (M-matrix) of charm quark and anti-charm quark non-perturbativly. By comparing it with the perturbative scattering matrix, the Sommerfeld enhancement factor is obtained.Furthermore,in a screened potential model, we numerically solve the LSE and compute the value of the Sommerfeld enhancement factor. Finally, we generalized our method and results to the case of p waves and finite quark widths.
[1] Xin Wu and Min He,in preparation(2019)
