Ruling out Color Transparency in Quasielastic C 12 (e,e′ p) up to Q2 of 14.2 (GeV/ c)2

Abstract

Quasielastic C12(e,e′p) scattering was measured at spacelike 4-momentum transfer squared Q2=8, 9.4, 11.4, and 14.2 (GeV/c)2, the highest ever achieved to date. Nuclear transparency for this reaction was extracted by comparing the measured yield to that expected from a plane-wave impulse approximation calculation without any final state interactions. The measured transparency was consistent with no Q2 dependence, up to proton momenta of 8.5 GeV/c, ruling out the quantum chromodynamics effect of color transparency at the measured Q2 scales in exclusive (e,e′p) reactions. These results impose strict constraints on models of color transparency for protons.