Abstract

The longitudinal spin transfer, D-LL, from high energy polarized protons to Lambda and Lambda hyperons has been measured for the first time in proton-proton collisions at s=200 GeV with the STAR detector at the Relativistic Heavy Ion Collider. The measurements cover pseudorapidity, eta, in the range |eta| 1.2 and transverse momenta, p(T), up to 4 GeV/c. The longitudinal spin transfer is found to be D-LL=-0.03 +/- 0.13(stat)+/- 0.04(syst) for inclusive Lambda and D-LL=-0.12 +/- 0.08(stat)+/- 0.03(syst) for inclusive Lambda hyperons with >=0.5 and p(T)>>=3.7 GeV/c. The dependence on eta and p(T) is presented.