Upper limit on the decay Sigma(1385)- --> Sigma- gamma, and cross section for gamma Sigma- --> Lambda pi-

TL;DR

This paper sets an upper limit on the decay width of Sigma(1385)- to Sigma- gamma and estimates the cross section for gamma Sigma- to Lambda pi- using high-energy hyperon interactions at Fermilab.

Contribution

It provides the first experimental upper limit on the radiative decay width of Sigma(1385)- and measures the cross section for gamma Sigma- interactions.

Findings

Upper limit on Gamma[Sigma(1385)- --> Sigma- gamma] < 9.5 keV

Estimated cross section for gamma Sigma- --> Lambda pi- is 56+/-16 mb

Study conducted with 600 GeV Sigma- hyperons at Fermilab

Abstract

Coherent Lambda pi- production on Pb of 600 GeV Sigma- hyperons has been studied with the SELEX facility at Fermilab. Using the Primakoff formalism, we set a 90% CL upper limit on the radiative decay width Gamma [Sigma(1385)- --> Sigma- gamma] < 9.5 keV, and estimate the cross section for gamma Sigma- --> Lambda pi- at sqrt(s) = 1.385 GeV to be 56+/-16 mkb.