Electroproduction of $\ddot{I}•(1020)$ mesons at $1.4\le Q^2\le$ GeV${}^2$ measured with the CLAS spectrometer

Abstract

Electroproduction of exclusive $\ddot{I}•$ vector mesons has been studied with the CLAS detector in the kinematical range $1.4\le Q^2\le 3.8$ GeV${}^2$, $0.0\le t^{\prime }\le 3.6$ GeV${}^2$, and $2.0\le W\le 3.0$ GeV. The scaling exponent for the total cross section as $1/(Q^2+M_{\ddot{I}}{•}^2{)}^n$ was determined to be $n=2.49\pm 0.33$. The slope of the four-momentum transfer $t^{\prime }$ distribution is $b_{\ddot{I}}•=0.98\pm 0.17$ GeV${}^{-2}$. Under the assumption of s-channel helicity conservation (SCHC), we determine the ratio of longitudinal to transverse cross sections to be $R=0.86\pm 0.24$. A 2-gluon exchange model is able to reproduce the main features of the data.

Phys Rev C, 15 pages, 18 figures