Hyperon polarization and vector meson production at 2.85 GeV (Preliminary Results)

Surprisingly large polarization in hyperon production by unpolarized proton beam has been known since long time. Huge inclusive hyperon polarization data are available in literature, few data are disponible on spin observables and none on exclusive hyperon measurements. Evidence of relevant violation of the OZI rule in several reactions are also shown in recent measurements. These two items, connected together by the hypothesis of existence of a sizeable $q \bar{q}$ sea in the nucleon, can be studied using the DISTO is a spectrometer installed in the polarized proton beam of the Saturne accelerator in Saclay. The compact experimental set-up is designed to detect four or more charged particles signaling $\Lambda$, $\Sigma^{0}$, $Y^{*}$ or $\phi$ production in $\vec{p} p$ interaction. An outline of the physical motivations and a brief description of the experimental apparatus is given as well as some preliminary results from the first production running