[en] Differential cross sections for π⁺p and π^-p elastic scattering have been measured at 8 momenta between 400 MeV/c and 590 MeV/c. Results are compared with previously published data

[en] According to the program of studying the πN interaction by means of a synchrocyclotron the polarization parameter has been measured in πsub(+-)p elastic scattering at the incident pion energy of 450 MeV, the measurements being carried out by the recoil proton secondary scattering method. A brief description is given of the experimental set up which consists of 24 wire spark chambers with magnetostrictive readout and time-of-flight analysis system. The obtained data are used to make the phase shift analysis at 450 MeV energy. The results are as well treated using the isospin invariance

[en] Differential cross sections for π⁺p and π^-p elastic scattering have been measured at 12 energies in the region 277-640 MeV. The data were obtained in the angular range THETAsup(*)π = 40⁰-176⁰, with a typical accuracy of 2-5%. The results for 288 MeV and 292.9 MeV are in good agreement with the data of Bussey et al. Using the data obtained, isopin bounds have been calculated for the charge-exchange scattering. It is shown that the charge-exchange cross sections at large angles are grouped near the bottom isospin limit, and at energies larger than 490 MeV they lie beyond the region allowed by isospin invariance. The comparison was carried out with the predictions of different phase-shift analyses. It is shown that the existing phase-shift analyses do not describe all the set of the new data. A new energy-independent phase-shift analysis has been carried out at 12 energies in the region 240-700 MeV. (orig.)

[en] Differential cross sections of elastic π⁺p scattering at energies of incident π-mesons of 442, 490, 530, 560, 600 MeV were measured along with those of π^-p scattering at energies of 425, 465, 490, 530, 560, 600, 640 MeV. Data were obtained in the angular range of THETAsub(π)* = 40-176 deg which had characteristic accuracy of 2-5%. The experiment was made on π-meson channel of a synchrocyclotron. The measurements were carried out using a 10-channel hogoscopic installation. Each hodoscope channel switched on the coincidence with the telescope of monitor counters, performed a simultaneous registration of protons and π-mesons escaping from the target at the angles corresponding to the kinematics of elastic πp scattering. The experimental installation is characterized by the usage of the time-of-flight technique in each hodoscope channel. Isospin boundaries for cross sections of the π^-p → π⁰n recharge were calculated based on the data obtained. It is shown that recharge cross sections for large scattering angles are grouped near the lower boundary, and at energies more than 490 MeV they lie outside the region permitted by isotopic invariance. The comparison with predictions of various phase analyses is made, and it is shown that neither of the existing phase analyses may satisfactorily discribe the whole totality of new data. The results of the experiment together with data on elastic π^+-p scattering for lower energies, which have a high accuracy, are a systematic interacoordinated collection of precise data which are the basis for a new phase analysis of πp scattering in the range of Psub(33-), Psub(11-), S₁₁ and D₁₃ resonances

[en] This paper presents the results of an experiment in which the polarization parameter P in π^-p elastic scattering has been measured at energies of 450, 490, 530, 560 and 600 MeV. The experiment was performed on a pion channel of the LNPI synchrocyclotron using a polarized proton target and wire spark chambers with magnetostrictive read-out. The results have substantially higher precision in comparison with other experiments in this energy range. (orig.)

[en] The differential cross-sections (DCS) of the η-production reaction π^-p→ηn are measured at momenta of incident π^- mesons (700, 710 and 720MeV/c) close to the threshold of this reaction. The experiment is carried out at the pion channel of the PNPI synchrocyclotron (with the momentum spread of the pion beam equal to 1.5%) using the Neutral Meson Spectrometer (NMS) designed and created at the Meson Physics Laboratory for detecting two photons from the decay η→2γ. This spectrometer consisting of two electromagnetic total absorption calorimeter (24 CsI(Na) crystals in each calorimeter) allowed to obtain the DCS in the whole angular range from 0 to 180 in the c.m.s. It is shown that at 700MeV/c the DCS angular dependence is isotropic, indicating on the S-wave character of the η-production process while at higher momenta a significant contribution of the D-wave has led to the anisotropic angular dependence having a bowl-like shape. (orig.)

[en] First measurement of the spin rotation parameters R and A in π-p elastic scattering in the region of pion-nucleon resonances has been performed at the Leningrad Nuclear Physics Institute. The experiment was carried out on a pion channel of the LNPI synchrocyclotron using a polarized target with LNPI synchrocyclotron using a polarized target with horizontally oriented polarization vector and a multi-plate carbon polarimeter consisting of optical spark chambers with television read-out. Results at the energies 450 and 560 MeV are given in comparison with the predictions of phase-shift analyses

No abstract available

[en] The polarization parameter P in elastic π^-p scattering has been measured at energies 450, 530, and 560 MeV in the interval -0.9< costheta*<0.6 in the π-meson beam of the synchrocyclotron at the Leningrad Institute of Nuclear Physics. The absolute error in the measurements is ΔPapprox. =0.1. The data are compared with the data of phase-shift analyses and with previous measurements

[en] This paper presents the results of an experiment in which the polarization parameter P in π⁺ p elastic scattering has been measured in the energy range from 335 to 580 MeV. The experiment was performed on a pion channel of the LNPI syncro-cyclotron using a polarized proton target and wire spark chambers with magnetostrictive read-out. The results have substantially higher precision in comparison with the most of other experiments in this energy range and allow to determine unambiguously the shape of angular dependence P(thetasup(*)) in the whole investigated region. New phase-shift analysis of π⁺p scattering data has been performed. The results of this experiment were used also to check isospin invariance. (orig.)