Conference Presentation (After Call)

PUBDB-2026-02986

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Beam-spin Induced Polarization of $Λ$ and Anti-$Λ$ Hyperons in Semi-Inclusive Deep-Inelastic Scattering

Marukyan, H. (Corresponding author)Extern* ; HERMES Collaboration (Collaboration author)DESY*

2026

Abstract: The beam-spin induced polarization of $\Lambda$ and $\bar\Lambda$ hyperons produced in deep-inelastic scattering of longitudinally polarized positrons from unpolarized nucleons has been investigated by the HERMES experiment at a positron beam energy of 27.6 GeV impinging on hydrogen, deuterium, and various heavier gas targets. The two spin-transfer coefficients $D_{LX}$ and $D_{LZ}$ (longitudinal-to-transverse and longitudinal-to-longitudinal, respectively) are extracted and are found to be small and mostly compatible with zero within their statistical and systematic uncertainties, essentially independent of the relevant kinematic variables. The results constrain novel spin-dependent fragmentation functions, among others the helicity fragmentation function describing the hadronization of longitudinally polarized quarks into longitudinally polarized hadrons.

Note: funded by the EU COST action No. 24159 (SHARP), and grant number 21AG-1C028 funded by the Ministry of Education, Science, Culture and Sports of the Republic of Armenia

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Contributing Institute(s):

1. HERMES Kollaboration (HERMES)

Research Program(s):

1. 611 - Fundamental Particles and Forces (POF4-611) (POF4-611)

Experiment(s):

1. HERA: HERMES

Appears in the scientific report 2026

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