Electroproduction of $\phi(1020)$ mesons at $1.4\leq Q^2\leq$ GeV$^2$ measured with the CLAS spectrometer

TL;DR

This study measures the electroproduction of $\, ext{phi}(1020)$ mesons using the CLAS detector, analyzing cross sections, t' distributions, and helicity ratios to understand the underlying production mechanisms in the specified kinematic range.

Contribution

It provides new measurements of cross sections, t' slopes, and helicity ratios for $\, ext{phi}$ meson electroproduction at intermediate $Q^2$, testing a 2-gluon exchange model against experimental data.

Findings

The total cross section scales with $Q^2$ as $(Q^2 + M_\, ext{phi}^2)^{-2.49}$.

The t' distribution slope is $0.98 \,\text{GeV}^{-2}$.

The ratio of longitudinal to transverse cross sections is approximately 0.86.

Abstract

Electroproduction of exclusive $\phi$ vector mesons has been studied with the CLAS detector in the kinematical range $1.4\leq Q^2\leq 3.8$ GeV$^{2}$, $0.0\leq t^{\prime}\leq 3.6$ GeV$^{2}$, and $2.0\leq W\leq 3.0$ GeV. The scaling exponent for the total cross section as $1/(Q^2+M_{\phi}^2)^n$ was determined to be $n=2.49\pm 0.33$. The slope of the four-momentum transfer $t'$ distribution is $b_{\phi}=0.98 \pm 0.17$ 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.