Measurement of nuclear transparency from A(e,e'[pi]⁺) reactions

Abstract

The color transparency phenomenon refers to the suppression of final-state interactions of a hadron propagating through the nuclear medium at large momentum transfer when the hadron is produced with small transverse size. The pion electroproduction cross section from 1H, 2H,12C, 63Cu and 197Au targets from Q2 = 1.1 to 4.8 (GeV/c)2 was measured in Jefferson Laboratory Experiment E01-107. The nuclear transparency was formed by the ratio of ([sigma]A/[sigma]H) from the data and ([sigma]A/[sigma]H) from a model of electroproduction from nuclei that does not include [pi]-N final state interactions. A signature of color transparency is the enhancement of the nuclear transparency at large Q2 compared with predictions based on Glauber multiple scattering theory. This experiment represents the first nuclear transparency data from (e,e'[pi]+) reactions.