Nuclear dependence of transverse momentum distributions for Drell-Yan, J/ Ψ , and Ψ ' production in p+p collisions at sqrt(s) =15.5 GeV

• Main Authors: SuYin Grass Wang, 王素音
• Other Authors: Rurng-Sheng Guo
• Format: Others
• Language: en_US
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/27636016636242881127

博士 === 國立高雄師範大學 === 物理學系 === 104 === The suppression of J/£Z and £Z' production due to the plasmas screening of strong interaction has been considered as one of the important signatures of the formation of quark-gluon-plasma in the nucleus-nucleus collisions. In order to establish the baseline of similar suppression effect caused by the cold nuclear matter, the measurement of nuclear dependence of transverse momentum spectrum of J/£Z, £Z' and Drell-Yan production in the proton-nucleus collisions is essential. Other than understanding the absorption of charmonium in the nuclear medium, it also provides valuable information of production mechanisms for J/£Z and £Z' and the interaction of fast-moving partons with the nuclear medium before the hard collisions. We performed such measurement in SeaQuest E906 experiment at Fermilab with 120-GeV proton beams. By comparison with the results of similar measurement by E772 and E866 with 800-GeV proton beams, we observe no change in the production and absorption of J/£Z and £Z' and slightly stronger initial-state interaction for quarks with nuclear medium at low energies.