Single Spin Asymmetries in Charged Kaon Production from Semi-Inclusive Deep Inelastic Scattering on a Transversely Polarized $^3{\rm{He}}$ Target

TL;DR

This study presents the first measurement of single spin asymmetries in charged kaon production from semi-inclusive deep inelastic scattering on a transversely polarized helium-3 target, providing insights into nucleon spin structure.

Contribution

It provides the first experimental extraction of Collins and Sivers moments for charged kaons on a transversely polarized helium-3 target, comparing results with theoretical predictions.

Findings

K+ moments are consistent with zero; K- moments favor negative values.

K+ Sivers moments agree with theoretical predictions.

K- Sivers moments differ from predictions at 2-sigma level.

Abstract

We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized $^3{\rm{He}}$ target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of 0.1$<$$x_{bj}$$<$0.4 for $K^{+}$ and $K^{-}$ production. While the Collins and Sivers moments for $K^{+}$ are consistent with zero within the experimental uncertainties, both moments for $K^{-}$ favor negative values. The Sivers moments are compared to the theoretical prediction from a phenomenological fit to the world data. While the $K^{+}$ Sivers moments are consistent with the prediction, the $K^{-}$ results differ from the prediction at the 2-sigma level.