Longitudinal and Transverse Spin Transfer of $\Lambda$ and $\overline{\Lambda}$ Hyperons in Polarized $p$+$p$ Collisions at $\sqrt{s} = 200$ GeV at RHIC-STAR

TL;DR

This paper reports new measurements of the longitudinal and transverse spin transfer to hyperons in polarized proton-proton collisions at RHIC, providing insights into the spin structure of the proton and polarized fragmentation functions.

Contribution

It presents the first results of hyperon spin transfer measurements with doubled data statistics, enhancing understanding of quark helicity and transversity distributions.

Findings

First measurement of hyperon $D_{LL}$ and $D_{TT}$ at RHIC.

Results with twice the previous data sample.

Implications for proton spin structure and fragmentation functions.

Abstract

Measurements of the longitudinal spin transfer, $D_{LL}$, and the transverse spin transfer, $D_{TT}$, of the $\Lambda(\bar{\Lambda}$) hyperon in polarized $p$+$p$ collisions are expected to be sensitive to the helicity distribution and transversity distribution of the $s(\bar{s})$ quark in proton and the corresponding polarized fragmentation functions. This contribution presents the new preliminary results of the $\Lambda(\bar{\Lambda}$) $D_{LL}$ and $D_{TT}$ using data collected at RHIC-STAR experiment in 2015, with twice larger statistics than previously published results.