A new experiment SPASCHARM for systematic study of polarization phenomena in inclusive and exclusive hadronic reactions is currently under commissioning at IHEP. The universal experimental setup will detect dozens of various resonances and stable particles produced in collisions of unpolarized beams with the polarized target, and at the next stage, using polarized beams. At the first stage with polarized target, the final states composed of light quarks (u, d, s) will be reconstructed. Hyperon polarization and spin density matrix elements of the vector mesons will be measured along with the single-spin asymmetries. The 2π-acceptance in azimuth, which is extremely useful for reduction of systematic errors in measurements of spin observables, will be implemented in the experiment. The solid angle acceptance of the setup, Δθ≈250 mrad vertically and 350 mrad horizontally in the beam fragmentation region, covers a wide range of kinematic variables pT and xF. This provides the opportunity for separating dependences on these two variables which is usually not possible in the setups with a small solid angle acceptance. Unlike some previous polarization experiments, the SPASCHARM will be able to simultaneously accumulate and record data on the both, charged and neutral particle production.

The results obtained by measuring, at the U-70 accelerator in Protvino, the single-spin asymmetry A N in the reaction p + p └ → π0 + X at a beam energy of 50 GeV in the Feynman variable range of −0.6 < x F < −0.1 are presented. The asymmetry A N is close to zero at small |x F | and grows in magnitude with |x F |, reaching 6.4% in the region of |x F | > 0.25. The results of these measurements agree with data of the E704 experiment on the asymmetry of π 0 mesons at the Fermi National Accelerator Laboratory in the region of polarized-beam fragmentation and with the results of measurements in the region of polarized-target fragmentation that were performed in Protvino by using a 40-GeV π −-meson beam and a 70-GeV proton beam.

A new experiment SPASCHARM devoted to a systematic study of polarization phenomena in hadron-hadron interactions in the energy range 10-70 GeV is under preparation at IHEP (Protvino). The physical observables will be single-spin asymmetries, hyperon polarizations and spin-density matrix elements. A universal setup will detect and identify various neutral and charge particles in the full azimuthal angle and a wide polar angle range. A polarized target is used to measure the SSA. The SPASCHARM sub-detectors are being designed and constructed now. The possibility of obtaining a polarized proton beam for the SPASCHARM experiment from Lambda decays is under study.

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.

A new single-spin asymmetry A(N) measurement has been carried out at IHEP at 50 GeV. A(N) was found to be -(6.2 +/- 1.5)% in the polarized target fragmentation region at -0.6 < x(F)<-0.25. The result proves that asymmetry does not depend on beam energy. A review of polarization results from Protvino as well as a proposal of the new experiment SPASCHARM are also presented.

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.

p and pp interactions at 40 and 70 GeV correspondingly. Signif-icant asymmetry was observed in the polarized target fragmentation region. The results are inagreement with ”universal threshold” of single-spin asymmetry.Keywords: single-spin asymmetry; polar-ization; polarized target fragmentation re-gion.

Single-spin asymmetries $A_N$ in reactions p+p(pol)->π^0 + X and π^-+p(pol)->π^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)->π^0 + X confirm this conclusion with better statistics and coincide with our previous data at 70 GeV/c for the same reaction.

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.

We present recent results of single-spin asymmetry A_N measurements in π^0 inclusive production. Asymmetry was measured in π^-p and pp interactions at 40 and 70 GeV correspondingly. Significant asymmetry was observed in the polarized target fragmentation region. The results are in agreement with "universal threshold" of single-spin asymmetry.

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 $π^-$-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 $Δg(x)$ extraction at large $x$.

New results for the np spin-dependent total cross section difference Δσ p ( np ) at neutron beam kinetic energies of 1.59, 1.79 and 2.20 GeV are presented. Measurements of the Δσ p ( np ) energy dependence were carried out at the Synchrophasotron of the Laboratory of High Energies of the Joint Institute for Nuclear Research in Dubna. The values of Δσ L were measured as a difference between the np total cross sections for parallel and antiparallel beam and target polarizations, both oriented along the beam momentum. A fast decrease of Δσ p ( np ) with increasing energy above 1.1 GeV, as it was first seen from our previous data, was confirmed. The new results are also compared with model predictions and with the phase shift analysis fits. The Δσ L quantities for isosinglet state I=0, deduced from the measured values of Δσ p ( np ) and known Δσ p ( pp ) data, are given.

A target with a frozen spin polarization of protons in 1.2-propanediol with a paramagnetic Cr(V) impurity is described, intended for polarization parameter studies in np-scattering at approximately 15 MeV neutron energy. The target of cylindrical shape of 2 cm diameter and 6 cm long with an initial polarization of 95 ± 3%, obtainable by the dynamic polarization technique, is placed at a temperature about 20 mK in a magnetic field of 0.37 T generated by a magnetic system, which provides a large aperture for scattered particles. The relaxation time for the spin polarization in an experiment is about 1000 hours.