Single-spin asymmetries in the leptoproduction of transversely polarized $\Lambda$ hyperons

TL;DR

This paper investigates single-spin asymmetries in leptoproduction of transversely polarized Lambda hyperons using collinear twist-3 formalism, introducing the first analysis of the fragmentation contribution in this context and confirming gauge invariance.

Contribution

It provides the first analysis of the fragmentation term for transversely polarized hadron production within the collinear twist-3 framework and verifies gauge invariance across gauges.

Findings

Fragmentation contribution analyzed for the first time in this context.

Results are gauge invariant between lightcone and Feynman gauges.

Methodology parallels previous work on pion production in p+p collisions.

Abstract

We analyze single-spin asymmetries (SSAs) in the leptoproduction of transversely polarized $\Lambda$ hyperons within the collinear twist-3 formalism. We calculate both the distribution and fragmentation terms in two different gauges (lightcone and Feynman) and show that the results are identical. This is the first time that the fragmentation piece has been analyzed for transversely polarized hadron production within the collinear twist-3 framework. In lightcone gauge we use the same techniques that were employed in computing the analogous piece in $p^\uparrow p\to \pi\,X$, which has become an important part to that reaction. With this in mind, we also verify the gauge invariance of the formulas for the transverse SSA in the leptoproduction of pions.