Data taking has been started at the first stage of the SPASCHARM experiment on systematic study of the spin effects in strong interactions. The current setup configuration is described, and the detector characteristics attained during the beam data taking in the runs of 2018–2022 are listed.

First results on Alpha-dependence measurements in inclusive K-S(0) meson production in pi(-)Alpha interactions (Alpha=C, Al, Cu, Sn, and W) are presented at approximate to 26.5 GeV/c. The ratios of the differential cross sections of four of these nuclei to the differential cross section on aluminum were measured and the dependence of these cross sections on the atomic of the nucleus was studied. The measurements were carried out in the kinematic region of the Feynman variable 0.2 < x(F) < 0.8 and transverse momentum p(T) < 1.2 GeV/c. K-S(0) mesons were detected in the decay mode K-S(0)->pi(+)pi(-) at the SPASCHARM experimental setup using negative charged beams at beamline 14 of the U-70 accelerator complex.

First results on 𝐴-dependence measurements in inclusive K0𝑆-meson production in 兀− 𝐴-interactions (𝐴 = C, Cu, Al, Sn, W) are presented at 26.5 GeV/c. The ratios of the differential cross sections of four of these nuclei to the differential cross section on aluminum were measured and the dependence of these cross-sections on the atomic number of the nucleus was studied. The measurements were carried out in the kinematic region of the Feynman variable 0.2 < 𝐹 < 0.8 and transverse momentum 𝑝𝑇 < 1.2 GeV/c. K0𝑆-mesons were detected in the decay mode K0𝑆→ 兀+兀−-at the SPASCHARM experimental setup using negative charged beams at beamline 14 of the U-70 accelerator complex.

First results on the polarization of Λ hyperons inclusively produced on 26.5-GeV/c K^ - and π^ - beams are presented. The measurements were carried out using the SPASCHARM setup at the U-70 accelerator facility (Protvino, Russia) on nuclear targets in 2021 and 2022. The polarization of an Λ hyperon on the π^ - beam does not exceed several percent in most of the studied kinematic region. The data obtained on the K^ - -meson beam exhibit a significant positive polarization at large values of the Feynman variable xF and transverse momentum pT measured for the first time on nuclei.

First results on A -dependence measurements in inclusive K_S^0 meson production in π^-A interactions ( A=C , Al, Cu, Sn, and W) are presented at ≈26.5 GeV/c. The ratios of the differential cross sections of four of these nuclei to the differential cross section on aluminum were measured and the dependence of these cross sections on the atomic of the nucleus was studied. The measurements were carried out in the kinematic region of the Feynman variable 0.2

The SPASCHARM experiment is aimed at a systematic study of the nucleon spin structure and the spin dependence of the strong interaction of antimatter and matter with matter at energies up to 45 GeV. As part of the first stage of the experiment, the study of the spin properties of hadrons will take place in a beam of negatively charged hadrons on existing beamline 14 at the operating SPASCHARM setup at the U70 facility. At the second stage, the production of polarized beams of protons and antiprotons is envisaged in beamline 24A of the U-70 accelerator facility. A polarized antiproton beam will certainly become a unique beam in the world. It is planned to measure single-spin asymmetries in dozens of reactions, both on hydrogen and on various nuclei. At the SPASCHARM facility, it is also possible to measure the transverse polarization of hyperons and elements of the spin density matrix of vector mesons. The spin structure of the nucleon will be investigated in the study of quarkonium production to determine the contribution of gluons to the proton spin. The presence of two types of polarized beams and eight types of nonpolarized beams (π ± , K ± , p , p̅ , d , C ), in combination with a polarized target, expands the range of studies of polarization phenomena and enhances the uniqueness of the project.

The analysis of high-precision $\pi^{\pm}p \to \pi^{\pm}p$ cross section data from the EPECUR Collaboration based on the multichannel $K$-matrix approach is presented.The sharp structures seen in these data are studied in terms of both opening thresholds and new resonance contributions. Some prominent features are found to be due to the opening $K\Sigma$ channel. However, a complete description of the data is improved with the addition of two narrow resonant structures at $W\sim 1.686$ and $W\sim 1.720$ GeV. These structures are interpreted as manifestations of $S_{11}$ and $P_{11}$ resonances. The underlying nature of the observed phenomena is discussed.

Cross sections for pi+-p elastic scattering have been measured to high precision, for beam momenta between 800 and 1240 MeV/c, by the EPECUR Collaboration, using the ITEP proton synchrotron. The data precision allows comparisons of the existing partial-wave analyses (PWA) on a level not possible previously. These comparisons imply that updated PWA are required.

The EPECUR experimental setup has been designed to search for narrow resonant states by precisely measuring differential and total reaction cross sections for pion-nucleon interactions with 1-MeV pion energy steps. Over the 5 years that passed from the submission of the idea of the experiment to the start of data taking in April 2009, a non-magnetic spectrometer with a liquid hydrogen target based on the large-aperture multiwire drift chambers with a hexagonal structure has been built at the universal beamline 322 of the U-10 proton synchrotron at the Alikhanov Institute for Theoretical and Experimental Physics. Owing to the unique properties of the beamline, the beam particle momentum can be measured with an accuracy of 0.1% or better using 1-mm-pitch proportional chambers located at the first focus of the beamline. The design of numerous subsystems of the setup is based on modern electronic components including microprocessors and field programmable gate arrays. All the subsystems have been tuned and tested both individually and as parts of the whole setup. The distributed data acquisition system is based on the widely spread USB and Ethernet protocols, which help achieve high performance characteristics and take full advantage of the industrial solutions.

The EPECUR collaboration presents new high precision data on the pion-proton elastic scattering in the second resonance region. The experiment EPECUR is placed on the universal beam channel of the accelerator ITEP. The setup features 0.1% beam pion momentum tagging system, 25 cm long liquid hydrogen target, placed in mylar container and beryllium outer shell, low material wire drift chambers and high performance DAQ. More than 3 billions of triggers have been collected. The data cover pion beam momentum range 0.8 - 1.3 GeV/c and 40-120 degrees center-of-mass scattering angle range for both positive and negative pions. The measured differential cross section has 2% statistical accuracy in 2 degrees angle and 5 MeV/c momentum intervals.

One of the main sources of the information about nuclear resonances are partial wave analyses (PWA) of pion-proton elastic scattering. Nearly all of the data available for PWA were obtained more than 20 years ago with old measurement techniques. The talk presents new high precision data obtained recently by the EPECUR collaboration. The experiment features high statistics and better than 1 MeV resolution in the invariant mass thus allowing searches for narrow resonances with the coupling to the πp channel as low as 5%. The experimental setup consists of a 25 cm long liquid hydrogen target in a non-magnetic spectrometer of wire drift chambers with hexagonal structure. The measurements started in 2009. 3 billions of triggers are already collected with positive and negative pion beams in the beam momentum range 820-1330 MeV/c.

The asymmetry parameter P was measured for the elastic pion-proton scattering in the very backward angular region of \( \theta_{{\rm CM}}^{}\) \( \approx\) 150 - 170° at several pion beam energies in the invariant-mass range containing most of the pion-proton resonances. The general goal of the experimental program was to provide new data for partial wave analyses in order to resolve their uncertainties in the baryon resonance region to allow the unambiguous baryon spectrum reconstructions. Until recently the parameter P was not measured in the examined domain that might be explained by the extremely low cross-section. At the same time the predictions of various partial wave analyses are far from agreement in some kinematic areas and specifically those areas were chosen for the measurements where the disagreement is most pronouncing. The experiment was performed at the ITEP U-10 proton synchrotron, Moscow, by the ITEP-PNPI Collaboration in the latest 5 years.

An experiment EPECUR, aimed at the search of the cryptoexotic non-strange member of the pentaquark antidecuplet, started its operation at a pion beam line of the ITEP 10 GeV proton synchrotron. The invariant mass range of the interest (1610-1770) MeV will be scanned for a narrow state in the pion-proton and kaon-lambda systems in the formation-type experiment. The scan in the s-channel is supposed to be done by the variation of the incident pi- momentum and its measurement with the accuracy of up to 0.1% with a set of 1 mm pitch proportional chambers located in the first focus of the beam line. The reactions under the study will be identified by a magnetless spectrometer based on wire drift chambers with a hexagonal structure. Because the background suppression in this experiment depends on the angular resolution, the amount of matter in the chambers and setup is minimized to reduce multiple scattering. The differential cross section of the elastic pi-p-scattering on a liquid hydrogen target in the region of the diffractive minimum will be measured with statistical accuracy 0.5% in 1 MeV steps in terms of the invariant mass. For KLambda-production the total cross section will be measured with 1% statistical accuracy in the same steps. An important byproduct of this experiment will be a very accurate study of Lambda polarization. The setup was assembled and tested in December 2008 and in April 2009 we had the very first physics run. About 0.5x10^9 triggers were written to disk covering pion beam momentum range 940-1135 MeV/c.

The main goal of this proposal is the search for a narrow cryptoexotic nucleon resonance by scanning of the π−p system invariant mass in the region (1610–1770) MeV with the detection of π−p and KΛ decays. The scan is supposed to be done by the variation of the incident π− momentum and its measurement with the accuracy of up to ±0.1% (better than 1 MeV in terms of the invariant mass in the whole energy range) with a set of proportional chambers located in first focus of the magneto‐optical channel. High sensitivity of the method to the resonance under search is shown. The secondary particles scattered from a liquid hydrogen target are detected by sets of the wire drift chambers equipped with modern electronics.Now it is achieved the pion beam momentum resolution better than 0.1% at Pπ = 1.5 GeV/c. The wire drift chambers are in preparation. The liquid hydrogen target is tested. The first experimental accelerator run can be at the end of 2008 year.

The existing models of baryons usually predict considerably more resonance (three or more in number) than it was found by investigation of elastic pion‐nucleon scattering. This disagreement invites further investigation of the pion‐nucleon interaction and among other things the measurement of spin rotation parameters A and R in the elastic pion‐nucleon scattering.Recent experiments of the PNPI and PNPI‐ITEP collaborations resolved a part of twofold ambiguities of the existing partial wave analyses (PWA). These results were used in the last PWA of the George Washington University group SP06. The proposal for the additional spin rotation parameters A and R measurement in the resonance region is motivated. Such additional measurements are necessary to resolve remaining twofold ambiguities of the existing PWAs.

The main goal of this proposal is the search for a narrow cryptoexotic nucleon resonance by scanning of tire pi(-)p system invariant mass in the region (1610-1770) MeV with the detection of pi(-)p and KA decays. The scan is supposed to be done by the variation of the incident pi(-) momentum and its measurement with the accuracy of up to +/- 0.1% (better than 1 MeV in terms of the invariant mass in the whole energy range) with a set of proportional chambers located in first focus of the magneto-optical channel. High sensitivity of the method to the resonance under search is shown. The secondary particles scattered from a liquid hydrogen target are detected by sets of the wire drift chambers equipped with modern electronics.Now it is achieved the pion beam momentum resolution better than 0.1% at P-pi=1.5 GeV/c. The wire drift chambers are in preparation. The liquid hydrogen target is tested. The first experimental accelerator run can be at the end of 2008 year.