2022 Impact factor 4.4
Particles and Fields
Eur. Phys. J. C 32, 221-228 (2004)
DOI: 10.1140/epjc/s2003-01357-3

A measurement of $\Lambda$ polarization in inclusive production by $\Sigma^{-}$ of 340 GeV /c in C and Cu targets

The WA89 Collaboration

(Received: 2 April 2003 / / Published online: 27 November 2003)

We have measured the polarization of $\Lambda$ hyperons produced inclusively by a $\Sigma^{-}$ beam of 340 ${\rm {\,GeV}\!/c}$ momentum in nuclear targets. From a sample of 9.5 millions of identified $\Lambda$ decays, polarizations were determined in the range xF>0.1 and $p_t\leq1.6$ ${\rm {\,GeV}\!/c}$. The polarization w.r.t. the production normal is mainly positive for $x_F \, \geq $ 0.3. At fixed values of xF, it increases with pt to a maximum between pt=0.5 and pt=1 ${\rm {\,GeV}\!/c}$ , and then decreases to zero or even negative values, in sharp contrast to the plateau above pt=1 ${\rm {\,GeV}\!/c}$ observed in inclusive $\Lambda$ production by protons.

© Società Italiana di Fisica, Springer-Verlag 2004