Weak Hyperon Production in ep Scattering

Abstract

We study the kinematics and cross section of the scattering process $e p \rightarrow e Σ^+$. The cross section is expressed in terms of complex form factors characterizing the hadron vertices. We estimate the cross section for small momentum transfer using known experimental information. To first order in the momentum transfer, we obtain a model independent result for the photon-exchange part of the cross section, which is completely determined by the decay width $Γ(Σ^+ \rightarrow pγ)$. For the kinematics of the parity violation experiment at MAMI, this first order result gives rise to a ratio of $(dσ/dΩ)_{ep\rightarrow eΣ^+}$ $/(dσ/dΩ)_{ep\rightarrow ep} \simeq 4.0\times 10^{-15}$. The $Z^0$-exchange and interference parts give much smaller contributions due to the suppression of the flavor changing weak neutral current in the standard model. Feasibility of the experimental measurement is briefly discussed.