A systematic study of the initial state in heavy ion collisions based on   the quark participant assumption
  We investigate the initial state geometric quantities of heavy ion collisions based on the quark participant assumption in the Glauber multiple scattering approach. A systematic comparison to the nucleon participant assumption has been presented and confronted with the charged multiplicity measurements in various collision systems. It is found that the quark participant based assumption can be important to understand the data in multiplicity production and the initial spatial eccentricity in small systems. 
Liang Zheng, Zhongbao Yin
nucl-th nucl-ex