Proton source size measurements in the eA->e'ppX reaction

TL;DR

This study measures the size of proton emission regions in electron-nucleus collisions, revealing dependence on atomic number and proton momentum, and provides the first measurement for helium.

Contribution

It introduces the first measurement of two-proton emission region size in helium and demonstrates dependence on atomic number and proton momentum.

Findings

Correlation enhancement matches theoretical predictions

Emission size varies with atomic number and proton momentum

First measurement of proton emission size in helium

Abstract

Two-proton correlations at small relative momentum q were studied in the eA(3He, 4He, C, Fe)-> e'ppX reaction at E_0 = 4.46 GeV using the CLAS detector at Jefferson Lab. The enhancement of the correlation function at small q was found to be in accordance with theoretical expectation. Emission region sizes were extracted and proved to be dependent on A and proton momentum. The size of the two-proton emission region on the lightest possible nucleus, He, was measured for the first time.