Transverse polarization measurement of Λ hyperons in pNe collisions at sNN = 68.4 GeV with the LHCb detector

Abstract

A measurement of the transverse polarization of the Λ and $\overline{\Lambda }$ hyperons in pNe fixed-target collisions at $\sqrt{{\mathrm{s}}_{\mathrm{NN}}}$ = 68.4 GeV is presented using data collected by the LHCb detector. The polarization is studied using the decay Λ → pπ⁻ together with its charge conjugated process, the integrated values measured are$$\begin{array}{c}{P}_{\Lambda }=0.029\pm 0.019\left(\text{stat}\right)\pm 0.012\left(\text{syst}\right),\\ P_{\overline{\Lambda }}=0.003\pm 0.023\left(\text{stat}\right)\pm 0.014\left(\text{syst}\right).\end{array}$$

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.