Longitudinal Spin Transfer to Lambda and anti-Lambda Hyperons in Polarized Proton-Proton Collisions at s**(1/2) = 200-GeV

The STAR collaboration
Phys.Rev.D 80 (2009) 111102, 2009.

Abstract (data abstract)
BNL-RHIC. The longitudinal spin transfer, $D_{LL}$, from high energy polarized protons to $\Lambda$ and $\bar{\Lambda}$ hyperons has been measured for the first time in proton-proton collisions at $\sqrt{s} = 200$ 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 $D_{LL} = -0.03 \pm 0.13(stat) \pm 0.04(syst)$ for inclusive $\Lambda$ and $D_{LL} = -0.12 \pm 0.08(stat) \pm 0.03(syst)$ for inclusive $\bar{\Lambda}$ hyperons with $<\eta>$ and $<p_{T}> = 3.7 GeV/c$. The dependence on $\eta$ and $p_{T}$ is presented. ***Updated $D_{LL}$ values using the new $\alpha_\Lambda=0.732$ published on PDG2020 are also presented in this HEPData entry.***

Version 2 modifications: In 2020, PDG updated the alpha_lambda value from 0.642 to 0.732. This value is used to calculate the Lambda polarization in this paper. In this revision the data tables have been updated accordingly.

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