Study of the color diffusion model in $^12$C(e,e'p)$ at Jefferson Lab 12 GeV kinematics*

In nuclear knockout reactions at high energies, quantum chromodynamics predicts the reduction of final-state interactions between the knocked-out particle and the nuclear medium, resulting in a rise of the nuclear transparency observable with increasing energies. This is the so-called color transparency phenomenon and is in contrast to regular Glauber theory, which predicts flat values for the nuclear transparency. A recent Jlab 12GeV experiment measured the nuclear transparency for Carbon in the $A(e,e’p)$ reaction between the $Q^2$-range of 8-14 GeV$^2$ and observed no apparent signs yet of a color transparency signal.

In this study, we use a relativistic Glauber model and implement color transparency using the color diffusion model, which parametrizes the evolution of a small sized hadron (reduced interactions) to its original size on its way out of the nucleus. We vary the parameters of the model and discuss which ranges could produce a color transparency calculation that is still in agreement with the observed JLab12 data. Finally, we discuss possible applications of this study to deuteron breakup measurements.