Constraints on the onset of color transparency from quasi-elastic $^{12}$C$(e,e'p)$ up to $Q^2=\,14.2\,$(GeV$/c)^2$

TL;DR

This study measured quasi-elastic electron scattering on carbon-12 at high momentum transfers to investigate the potential onset of color transparency, finding results consistent with traditional nuclear physics and not supporting color transparency effects.

Contribution

First high-Q^2 measurements of nuclear transparency and shell-specific proton transparency in $^{12}$C, testing color transparency predictions at unprecedented momentum transfers.

Findings

Nuclear transparency aligns with traditional nuclear physics models.

No evidence of color transparency onset up to $Q^2=14.2$ (GeV/c)^2.

Shell-specific proton transparency measurements conducted.

Abstract

Quasi-elastic scattering on $^{12}$C$(e,e'p)$ was measured in Hall C at Jefferson Lab for space-like 4-momentum transfer squared $Q^2$ in the range of 8--14.2\,(GeV/$c$)$^2$ with proton momenta up to 8.3\,GeV/$c$. The experiment was carried out in the upgraded Hall C at Jefferson Lab. It used the existing high momentum spectrometer and the new super high momentum spectrometer to detect the scattered electrons and protons in coincidence. The nuclear transparency was extracted as the ratio of the measured yield to the yield calculated in the plane wave impulse approximation. Additionally, the transparency of the $1s_{1/2}$ and $1p_{3/2}$ shell protons in $^{12}$C was extracted, and the asymmetry of the missing momentum distribution was examined for hints of the quantum chromodynamics prediction of Color Transparency. All of these results were found to be consistent with traditional nuclear physics and inconsistent with the onset of Color Transparency.