Transverse polarization measurement of $\Lambda$ hyperons in $p$Ne collisions at $\sqrt{s_{NN}}$ = 68.4 GeV with the $\mbox{LHCb}$ detector

TL;DR

This paper reports the first measurement of transverse polarization of $\Lambda$ hyperons in proton-neon collisions at 68.4 GeV using the LHCb detector, providing insights into hyperon spin phenomena in fixed-target experiments.

Contribution

It presents the first measurement of $\Lambda$ and $ar{\Lambda}$ hyperon polarization in $p$Ne collisions at this energy with detailed kinematic dependence analysis.

Findings

Measured $\Lambda$ polarization: 0.029 ± 0.019 (stat) ± 0.012 (syst)

Measured $\bar{\Lambda}$ polarization: 0.003 ± 0.023 (stat) ± 0.014 (syst)

Results compared with previous measurements and show small polarization values.

Abstract

A measurement of the transverse polarization of the $\Lambda$ and $\bar{\Lambda}$ hyperons in $p$Ne fixed-target collisions at $\sqrt{s_{NN}}$ = 68.4 GeV is presented using data collected by the LHCb detector. The polarization is studied using the decay $\Lambda \rightarrow p \pi^-$ together with its charge conjugated process, the integrated values measured are $$ P_{\Lambda} = 0.029 \pm 0.019 \, (\rm{stat}) \pm 0.012 \, (\rm{syst}) \, , $$ $$ P_{\bar{\Lambda}} = 0.003 \pm 0.023 \, (\rm{stat}) \pm 0.014 \,(\rm{syst}) \,. $$ Furthermore, the results are shown as a function of the Feynman~$x$~variable, transverse momentum, pseudorapidity and rapidity of the hyperons, and are compared with previous measurements.