The First Stage of Polarization Program Spascharm at the Accelerator U-70 of Ihep

The first stage of the proposed polarization program SPASCHARM includes the measurements of the single-spin asymmetry (SSA) in exclusive and inclusive reactions with production of stable hadrons and the light meson and baryon resonances.In this study we foresee of using the variety of the unpolarized beams (pions, kaons, protons and antiprotons) in the energy range of 30-60 GeV. The polarized proton and deuteron targets will be used for revealing the flavor and isotopic spin dependencies of the polarization phenomena. The neutral and charged particles in the final state will be detected.

The Completion of Single-Spin Asymmetry Measurements at the Proza Setup

Single spin asymmetry in inclusive $pi^0$-production was measured in the polarized target fragmentation region using 50 GeV proton beam. The asymmetry is in agreement with asymmetry measurements in the polarized beam fragmentation region carried out at higher energies. The measurement completed 30-years history of polarized measurements at the PROZA setup.

New Polarization Program at U70 (SPASCHARM Project)

The new polarization program SPASCHARM is being prepared in Protvino. The program has two stages. The first stage is dedicated to single-spin asymmetries in the production of miscellaneous light resonances with the use of 34 GeV $pi^-$-beam. Inclusive and exclusive reactions will be studied simultaneously. The second stage is dedicated to single-spin and double-spin asymmetries in charmonium production with the use of 70 GeV polarized proton beam which will allow us to understand charmonium hadronic production mechanism and make gluon polarization $Delta g(x)$ extraction at large $x$.

The Comparative Study of the Inclusive $pi^0$ Analyzing Power in Reactions p+p(pol)->pi^0 + X and pi^-+p(pol)->pi^0 + X at 50 and 40 Gev/C Respectively

Single-spin asymmetries $A_N$ in reactions p+p(pol)->pi^0 + X and pi^-+p(pol)->pi^0 + X at 50 and 40 GeV/c respectively behave in drastically different ways in function of transverse momentum in the central region. At the same time $A_N$ in the polarized proton fragmentation region of these reactions are practically coinciding. Our new data on the analyzing power at 50 GeV/c in the polarized proton fragmentation region in reaction p+p(pol)->pi^0 + X confirm this conclusion with better statistics and coincide with our previous data at 70 GeV/c for the same reaction.