Measurement of transverse $\mathrm{\Lambda }$ and $\bar{\mathrm{\Lambda }}$ hyperon polarization in $p$Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV

The transverse polarization of $\mathrm{\Lambda }$ and $\bar{\mathrm{\Lambda }}$ hyperons is measured in $p$Pb collisions collected by the LHCb experiment at a nucleon-nucleon center-of-mass energy of $5.02$ TeV. The polarization is averaged over hyperon transverse momentum in the ranges $0.15<p_T<6.00$ GeV/$c$, and Feynman-$x$ in the ranges $0.005<x_F<0.040$ (forward region) and $-0.10<x_F<-0.01$ (backward region) defined relative to the proton beam direction. The transverse polarization is found to be compatible with zero for both $\mathrm{\Lambda }$ and $\bar{\mathrm{\Lambda }}$ hyperons. The results are also measured as a function of $p_T$ and $x_F$ with no significant dependence on these variables observed. The results are compared with previous experimental measurements at different center-of-mass energies and collision environments.