Electroproduction of the $\Lambda(1520)$ hyperon

TL;DR

This study investigates the electroproduction of the $ ext{Lambda}(1520)$ hyperon, analyzing angular distributions and dependencies on kinematic variables to understand the underlying production mechanisms at specific energies.

Contribution

It provides the first measurement of the $Q^2$ dependence of the $ ext{Lambda}(1520)$ decay angular distribution and highlights the dominance of t-channel processes in its electroproduction.

Findings

t-channel diagrams dominate the production process

60% of the yield from $m_z=\pm1/2$ parentage

Q^2$ dependence similar to $ ext{Lambda}(1116)$ production

Abstract

The reaction $ep \to e'K^+\Lambda(1520)$ with $\Lambda(1520) \to p'K^-$ was studied at electron beam energies of 4.05, 4.25, and 4.46 GeV, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cos$\theta_{K^+}$, $\phi_{K^+}$, $Q^2$, and $W$ dependencies of $\Lambda$(1520) electroproduction are presented for the kinematic region 0.9 $<$ $Q^2$ $<$ 2.4 GeV$^2$ and 1.95 $<$ $W$ $<$ 2.65 GeV. Also, the $Q^2$ dependence of the $\Lambda$(1520) decay angular distribution is presented for the first time. The cos$\theta_{K^+}$ angular distributions suggest {\it t}-channel diagrams dominate the production process. Fits to the $\Lambda$(1520) {\it t}-channel helicity frame decay angular distributions indicate the $m_{z}=\pm{1/2}$ parentage accounts for about 60% of the total yield, which suggests this reaction has a significant contribution from {\it t}-channel processes with either K$^+$ exchange or longitudinal coupling to an exchanged K$^*$. The $Q^2$ dependence of the $\Lambda$(1520) production cross section is the same as that observed for $\Lambda$(1116) photo- and electroproduction.