相对论重离子对撞机上重味衰变电子的测量数据中粲和底成分的分离

Charm and Beauty Separation from Heavy Flavor Electron Measurements at RHIC

重味夸克(即粲和底),尤其是底夸克,具有预期不同于轻夸克的性质,被认为是夸克胶子等离子体的理想探针。然而,很少有对底强子或其衰变的轻子的测量。利用最近相对论重离子对撞机上(√^(S)NN)=200 GeV的金核-金核碰撞中产生于中心快度下的粲强子和重味衰变电子的测量数据,我们发展了一种数据驱动的方法,用于分离重味衰变电子中粲和底的成分。从粲强子的测量数据出发,通过模拟其半轻子衰变得到粲衰变电子,从而从重味衰变电子中提取出底的成分。初步的结果展示了在最小偏向的金核-金核碰撞中粲和底衰变电子的横动量谱、核修正因子和椭圆流的分布。在中等至较高横动量区,相比于粲衰变电子的核修正因子,底衰变电子的核修正因子受到了较小的压制;在较低至中等横动量区,底衰变电子获得了比粲衰变电子更小的椭圆流。

Heavy quarks(charm and beauty),especially beauty,with expectedly different properties from light quarks are considered as ideal probes for the Quark-Gluon Plasma(QGP).However,there are few measurements on beauty hadrons or on their decay leptons.With the most recent measurements on charmed hadrons and heavy flavor decay electrons(HFE)at mid-rapidity in Au+Au collisions at√^(S)NN1/2=200 GeV at RHIC,a data-driven method is developed to separate charm and beauty components from the HFE measurements.From charmed hadron measurements,electrons from charm decays via semileptonic decay simulations are obtained,with which the beauty component can be extracted from the HFE spectrum.As preliminary results,the p_(T)spectra,RAA and v2 distributions of electrons from charm and from beauty decays(R_(AA)^(c→e)and v_(2)^(c→e),RAAb→e and v_(2)^(b→e))in minimum bias Au+Au collisions are presented,respectively.Less suppression of RAAb→e is observed compared with that of R_(AA)^(c→e)at moderate-to-high p_(T),and v_(2)^(b→e)shows smaller than v_(2)^(c→e)at low-to-moderate p_(T).