Polarization of Lambda and Anti-Lambda in 920 GeV Fixed-Target Proton-Nucleus Collisions

Abstract

A measurement of the polarization of Lambda and Anti-Lambda baryons produced in pC and pW collisions at sqrt(s)=41.6 GeV has been performed with the HERA-B spectrometer. The measurements cover the kinematic range of 0.6 GeV/c < p_T<1.2 GeV/c in transverse momentum and -0.15<x_F<0.01 in Feynman-x. The polarization results from the two different targets agree within the statistical error. In the combined data set, the largest deviation from zero, +0.054 +- 0.029, is measured for x_F < -0.07. Zero polarization is expected at x_F=0 in the absence of nuclear effects. The polarization results for the Lambda agree with a parametrization of previous measurements which were performed at positive x_F values, where the Lambda polarization is negative. Results of Anti-Lambda polarization measurements are consistent with zero.

11 pages, 3 figures

References in corpus (4)

• Big Bang Nucleosynthesis (in "The Review of Particle Properties" 2004)
• The Outer Tracker Detector of the HERA-B Experiment Part I: Detector
• Improved Measurement of the b-bbar Production Cross Section in 920 GeV Fixed-Target Proton-Nucleus Collisions
• The Outer Tracker Detector of the HERA-B Experiment. Part II: Front-End Electronics

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