Observation of a Coherence Length Effect in Exclusive Rho^0 Electroproduction

TL;DR

This study observes a coherence length effect in exclusive rho^0 electroproduction, revealing how quark-antiquark fluctuations interact with nuclear media, with implications for understanding quantum chromodynamics in nuclei.

Contribution

First experimental evidence of the coherence length effect in rho^0 electroproduction across multiple nuclear targets, demonstrating interaction with nuclear medium.

Findings

Nuclear transparency decreases with increasing coherence length.

Clear evidence of quark-antiquark fluctuation interactions with nuclei.

Data supports models of quantum chromodynamics in nuclear environments.

Abstract

Exclusive incoherent electroproduction of the rho^0(770) meson from 1H, 2H, 3He, and 14N targets has been studied by the HERMES experiment at squared four-momentum transfer Q**2>0.4 GeV**2 and positron energy loss nu from 9 to 20 GeV. The ratio of the 14N to 1H cross sections per nucleon, known as the nuclear transparency, was found to decrease with increasing coherence length of quark-antiquark fluctuations of the virtual photon. The data provide clear evidence of the interaction of the quark- antiquark fluctuations with the nuclear medium.