Longitudinal Spin Transfer to $\Lambda$ and $\bar{\Lambda }$ Hyperons in Polarized Proton-Proton Collisions at $\sqrt{s}$ = 200 GeV

Abstract

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 $\sqrt{s}=200\mathrm{GeV}$ with the STAR detector at RHIC. The measurements cover pseudorapidity, $\eta$, in the range $|\eta |<1.2$ and transverse momenta, $p_{\mathrm{T}}$, up to $4\mathrm{GeV}/c$. The longitudinal spin transfer is found to be $D_{LL}=-0.03\pm 0.13(\mathrm{stat})\pm 0.04(\mathrm{syst})$ for inclusive $\Lambda$ and $D_{LL}=-0.12\pm 0.08(\mathrm{stat})\pm 0.03(\mathrm{syst})$ for inclusive $\bar{\Lambda }$ hyperons with $<\eta >=0.5$ and $<p_{\mathrm{T}}>=3.7\mathrm{GeV}/c$. The dependence on $\eta$ and $p_{\mathrm{T}}$ is presented.

5 pages, 4 figures

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• PYTHIA 6.4 Physics and Manual
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• Longitudinal double-spin asymmetry and cross section for inclusive jet production in polarized proton collisions at sqrt(s) = 200 GeV
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