Suppression of Spin Transfer to $\Lambda$ Hyperon in Deep-Inelastic Scattering

TL;DR

This study examines how target fragmentation suppresses spin transfer to Lambda hyperons in deep-inelastic scattering, highlighting the importance of considering both current and target fragmentation regions for accurate spin effect analysis.

Contribution

It introduces a model that accounts for target fragmentation, improving the description of spin transfer data in deep-inelastic scattering experiments.

Findings

Spin transfer is significantly suppressed by target fragmentation.

Experimental data aligns with the model when target fragmentation is included.

Current and target fragmentation regions are not clearly separated at fixed-target energies.

Abstract

We investigate $\Lambda$ production in semi-inclusive deep-inelastic scattering using a polarized lepton beam and find that the spin transfer is significantly suppressed by target fragmentation. As further demonstrated by a model estimation, experimental data can be well described once the target fragmentation is taken into account, which alleviates the tension with calculations solely based on current fragmentation. Our findings suggest that, at the energies of existing fixed-target experiments, the separation of current and target fragmentation regions is not distinct. Spin transfer as well as other spin effects offers a sensitive probe into the origin of the produced hadron.