Λ0Hyperon Polarization in Inclusive Production by 300-GeV Protons on Beryllium

Abstract

${\Lambda }^0$ polarization has been observed in $p+\mathrm{Be}\to {\Lambda }^0+\mathrm{anything}$ at 300 GeV. A total of 1.2 × ${10}^6$ ${\Lambda }^0$ decays were recorded at fixed lab angles between 0 and 9.5 mrad, covering a range of kinematic variables $0.3<~x<~0.7$ and $0<~p_{\perp }<~1.5$ GeV/c. The observed polarization was consistent with parity conservation and increased monotonically with increasing $p_{\perp }$, independently of $x$, reaching $P_{\Lambda }=0.28\mathrm{}\pm 0.08$ at 1.5 GeV/c.