Color transparency in the reaction nuclear rho production by virtual photons

Abstract

We study the nuclear transparency $T$ for the exclusive reaction ${\gamma }^{\ast }+A\to \rho +p+(A-1{)}^{\ast }$ at incident virtual photon energies $\nu \ge$ 10 GeV %where the final state of the $A-1$-nucleon system is a one-hole state of the initial nucleus, to investigate the separate dependence on the photon virtuality, $Q^2$ and the 4-momentum-transfer-squared to the knocked-out proton, $t$. If the effects of color transparency are included, $T$ shows significant variation with $t$ even for small values of $Q^2$ for fixed values of the coherence length $l_c$, and also shows significant increase as $Q^2$ is increased at fixed $l_c$ and $t$. The value of $T$ is found to depend strongly on the phase space over which it is measured.

Comments: 22 pages, 10 figures