Polarization of Lambda0 and antiLambda0 inclusively produced by 610GeV/c Sigma- and 525GeV/c proton beams

TL;DR

This study measures the polarization of Lambda0 and antiLambda0 particles produced by high-energy Sigma- and proton beams, revealing different polarization behaviors depending on the beam type and kinematic variables.

Contribution

It provides new experimental data on Lambda0 and antiLambda0 polarization dependence on xF and pt for Sigma- and proton beams at high energies.

Findings

Lambda0 polarization increases with xF for Sigma- beam

Lambda0 polarization is negative and decreases with xF for proton beam

AntiLambda0 polarization is consistent with zero across all conditions

Abstract

We have measured the polarization of Lambda0 and antiLambda0 inclusively produced by 610GeV/c Sigma- and 525GeV/c proton beams in the experiment SELEX during the 1996/7 fixed target run at Fermilab. The polarization was measured as a function of the Lambda longitudinal momentum fraction xF and transverse momentum pt. For the Lambda0 produced by Sigma- the polarization is increasing with xF, from slightly negative at x_F~0 to about 15% at large xF; it shows a non-monotonic behavior as a function of pt. For the proton beam, the Lambda0 polarization is negative and decreasing as a function of xF and pt. The antiLambda0 polarization is compatible with 0 for both beam particles over the full kinematic range. The target dependence was examined but no statistically significant difference was found.