Color Transparency in Semi-Inclusive Electroproduction of rho Mesons

TL;DR

This paper investigates color transparency effects in rho meson electroproduction within nuclei, analyzing how these effects vary with energy, nuclear size, and experimental conditions, and providing detailed theoretical calculations aligned with experimental kinematics.

Contribution

The study introduces a detailed Glauber model including energy loss and decay effects, offering new insights into the magnitude of color transparency in rho meson production at intermediate energies.

Findings

Color transparency effects exceed 10% for Q^2 > 5 GeV^2.

Decay effects inside the nucleus are about 5% and diminish rapidly with increasing Q^2.

Experimental resolution impacts transparency measurements but does not account for observed effects.

Abstract

We study the electroproduction of rho mesons in nuclei at intermediate energies, deriving a treatment of the energy lost by the rho in each step of multiple-scattering. This enables a close match between calculations and the experimental kinematic conditions. A standard Glauber calculation is presented, and then the effects of color-transparency are included. The influence of poor experimental resolution on the extracted transparency is assessed. The effects of $\rho$ meson decay inside the nucleus are examined, and are typically about 5 percent at most. This effect disappears rapidly as $Q^2$ increases from about 1 to 3 GeV$^2$, causing a rise in the transparency that is not attributable to color transparency. The size of color transparency effects for C and Fe nuclei is studied for values of $Q^2$ up to 10 GeV$^2$. The detailed results depend strongly on the assumed value of the $\rho N$ cross section. The overall effects of color transparency are greater than about 10 % for both nuclear targets if $Q^2$ is greater than about 5 GeV$^2$.