Measurement of transverse Λ and Λ¯ hyperon polarization in pPb collisions at √sNN = 5.02  TeV

The transverse polarization of Λ and Λ¯ hyperons is measured in pPb 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 range 0.15<pT<6.00  GeV/c, and Feynman-x in the ranges 0.005<xF<0.040 (forward region) and -0.10<xF<-0.01 (backward region) defined relative to the proton beam direction. The transverse polarization is found to be compatible with zero for both Λ and Λ¯ hyperons. The results are also measured as a function of pT and xF 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.