Study of Lambda-hyperon polarization in the COMPASS experiment

The main interest in this measurement is to test the model of polarized int rinsic proton strangeness, which predicts that in deep-inelastic lepton sca ttering, the Lambda hyperons created in the target-fragmentation region sho uld have a large negative longitudinal polarization. The discovery of this effect will provide important information on the fundamental properties of the nucleon, such as the role of the (s) over bar s pairs in the proton wav e function. The measurement of the Lambda polarization in the current-fragm entation region will allow us to investigate another phenomenon-spin transf er in polarized-quark fragmentation to a polarized baryon. We have investig ated the possibilities of the COMPASS spectrometer for the measurement of h polarization. The COMPASS experiment can provide Lambda-polarization measu rement in the deep-inelastic-scattering process with high statistics, which exceed the existing data by about two orders of magnitude.