报告题目:Charm flow in heavy-ion collisions, High Level Trigger and Heavy Flavor Tracker
报告人:劳伦斯伯克利的博士后仇浩
地点:C911
时间:11月3日14:30--15:30
邀请人:徐庆华
Lawrence Berkeley National Lab
Institute of Modern Physics, Chinese Academy of Sciences
Results from RHIC and LHC support the creation of a strongly-coupled Quark-Gluon Plasma (sQGP) in heavy ion collisions. Heavy quarks (c, b) experience the whole evolution of the hot and dense medium, and are considered as a unique probe to the medium. Charm quarks are expected to thermalize much more slowly than light flavor quarks. As a result, the charm quark flow can be used to study the extent of thermalization of the bulk medium dominated by light quarks and gluons. Two sequential attempts to address the charm flow question at RHIC energy using J/ψ and D0 are reported. The High Level Trigger, an online computing framework, is developed to select interesting rare events, for example with J/ψ candidates. And the Heavy Flavor Tracker, a state-of-the-art high resolution silicon vertex detector, is constructed to improve measurements of open heavy flavor like D0. The measured J/ψ elliptic flow v2 is consistent with 0 for pT > 2 GeV/c, which is consistent with a picture that J/ψ are dominantly produced by initial production rather than coalescence from charm quarks. The measured D0 v2 suggests that charms quark exhibit finite collective behavior. There is also an indication that charm quarks are not fully thermalized in the medium created at RHIC.