V. V. Zhurkin

Measurements of spin rotation parameter A in pion proton elastic scattering at 1.62-GeV/c

Abstract The ITEP-PNPI Collaboration presents the results of the measurements of the spin rotation parameter A in the elastic scattering of positive and negative pions on protons at Pbeam=1.62 GeV/c. The setup included a longitudinally-polarized proton target with superconductive magnet, multiwire spark chambers and a carbon polarimeter with thick filter. Results are compared with the predictions of partial wave analyses. The experiment was performed at the ITEP proton synchrotron, Moscow.

Measurement of the spin rotation parameter A+ in the elastic scattering of positive pions on a longitudinally-polarized proton target in the second resonance region

Abstract The ITEP-PNPI collaboration presents the first results of the spin rotation parameter A+ measurements in the second resonance region. The experiment was performed at the ITEP accelerator at a positive pion beam momentum 1.43 GeV/c for scattering angles θcm = 127° and 133°. The setup was based on a polarized proton target and a carbon-plate polarimeter. The obtained data is compared with the predictions of the existing partial-wave analyses.

Measurement of the spin rotation parameter Ain the elastic pion-proton scattering at 1.43 GeV/c

Abstract.The ITEP-PNPI collaboration presents new results of the measurements of the spin rotation parameter A in the elastic scattering of negative pions on protons at Pbeam = 1.43 GeV/c. The results are compared to the predictions of several partial wave analyses. The experiment was performed at the ITEP proton synchrotron, Moscow.

Asymmetry Measurement in the Elastic Pion‐Proton Scattering at 1.94 and 2.07 GeV/c

Latest results by the ITEP‐PNPI collaboration on the asymmetry in the π+p elastic scattering are presented. The data were obtained for the first time in the region of backward angles with low cross section, where the predictions of the partial wave analyses are not reliable. The results at 1.94 GeV/c are in favor of the older KH80 analysis and show noticeable deviation from the latest FA06 solution by GWU group. At 2.07 GeV/c very low cross section did not allow to achieve good accuracy. Yet the data do not follow any of the PWA predictions and definitely disagree with SP06 analysis.

Program of measurement of the asymmetry P at the minima of the differential cross section for elastic π+p scattering

A program of measurement of the polarization parameter P in elastic π+p interaction in the resonance region of backward pion scattering is presented. This program is aimed at determining the bifurcation points of the trajectory of zeros of the pion-nucleon amplitude and, hence, at unambiguously reconstructing the amplitude of πN scattering in the second resonance region. It is planned to perform a relevant experiment in a pion beam from the accelerator of the Institute of Experimental and Theoretical Physics (ITEP, Moscow).

Measurement of the Spin Rotation Parameter A in the Elastic Pion‐proton Scattering at 1.43 GeV/c

The ITEP‐PNPI collaboration presents new results of the measurements of the spin rotation parameter A in the elastic scattering of negative pions on protons at Pbeam = 1.43 GeV/c. The results are compared to the predictions of the different partial wave analyses. The experiment was performed at the ITEP proton synchrotron, Moscow.

Measurement of spin-rotation parameters in elastic π+p scattering at a momentum of 1.62 GeV/c and calibration of a carbon polarimeter

Experimental data on the spin-rotation parameters A and R in elasticπ+p interaction were obtained for the first time at a momentum of pπ = 1.62 GeV/c. These data are necessary for unambiguously reconstructing the amplitude of pion-nucleon scattering and, hence, for deducing a correct spectrum of nonstrange baryon resonances. In order to obtain results for the polarization parameters A and R with the minimum possible systematic error, the carbon polarimeter used was preliminarily calibrated in a dedicated experiment; that is, the analyzing power was measured in proton-carbon scattering for incidentproton energies in the range Tp=0.7–1.3 GeV. The experimental data reported in the present article were obtained by a collaboration of researchers from the Petersburg Nuclear Physics Institute and Institute of Theoretical and Experimental Physics (ITEP, Moscow) at the ITEP synchrotron.

New Results on Spin Rotation Parameter A in the πp‐elastic Scattering in the Resonance Region

The paper presents new experimental data on the spin rotation parameter A obtained recently by ITEP‐PNPI collaboration at the ITEP accelerator. The set of measurements was performed in carefully chosen critical points with precision sufficient for choosing the correct branches of partial wave analyses. The data for both π+ and π−‐scattering at 1.0, 1.43 and 1.62 GeV/c is included.

Polarization experiments with the SPIN setup at the ITEP synchrotron

New experimental data on the spin-rotation parameters A and R measured for elastic π±p scattering in the resonance region and on the asymmetry in pC scattering at primary momenta in the range 1.35–2.02 GeV/c, as well as in quasielastic proton scattering on nuclei in the same momentum range, are summarized. All these data were recently obtained by using the proton synchrotron installed at the Institute of Theoretical and Experimental Physics (ITEP, Moscow). The spectrum and features of seven isospin-3/2 baryon resonances that form a peak in the total cross section at a c.m. energy of 1.9 GeV are analyzed on the basis of new data on the parameters A and R, and the results of this analysis are presented. The experiments surveyed in this article were performed by a collaboration of researchers from ITEP and the Petersburg Nuclear Physics Institute (PNPI, Gatchina), the ITEP-PNPI collaboration.

Measurement of spin rotation parameter A+ in π +p elastic scattering

Abstract The ITEP-PNPI collaboration presents first results of the spin rotation parameter A+ measurements in the second resonance region. The experiment was performed on ITEP accelerator at positive pion beam momentum 1·43 GeV/c (√s= 1·90 GeV/c) for scattering angles 0cm = 127° and 133°. Main parts of the setup were a polarized proton target and a carbon-plate polarimeter. The results of measurements are in agreement with the predictions of the partial-wave analysis VPI and in contradiction with the predictions of PWAs KH and CMB.