V.F. Grushin

Multipole analysis of pion photoproduction on protons near P33 (1236) resonance

The results of an energy-independent multipole analysis of pion photoproduction on protons are presented for the region of the P33 resonance. The analysis includes the phenomenological fitting of the experimental data by the linear model. We have obtained the channel amplitudes of the γp→nπ+ process without using the Watson theorem and the isospin amplitudes of the γp→nπ+ and γp→pπ0 processes using the πN phase shifts. All the results are discussed and compared with the theoretical predictions. From the channel amplitudes obtained an attempt has been made to evaluate the phases of M1+(3).

POSITIVE PION PHOTOPRODUCTION FROM HYDROGEN AT LARGE ANGLES IN THE REGION OF THE FIRST RESONANCE.

Abstract The results of measurement of differential cross sections for the process γp → nπ+ are presented for γ-ray energies 260, 290, 320 MeV and pion angles 90°–180°.

Analysis of angular distributions for the process γp → nπ+ in the region of 230–350 MeV

Abstract The results of the phenomenological analysis of the positive photopion angular distributions are presented for the photon energies 230, 260, 290, 320 and 350 MeV. Along with the Moravcsik fit a new form of fitting is used.

Ambiguity of multipole analysis and new amplitudes of the γp → nπ+ process

Abstract A multipole analysis of the γ p → n π + process using new data on the angular distributions of the polarized photon asymmetry has been made. At present the difference between the phase of the resonance amplitude M 1+ 3 2 and the corresponding πN scattering phase shift is found to be −2.5° ± 1.1°. The problem of the ambiguous solutions of a system of equations with respect to the multipole amplitude has been discussed.

Positive Pion Stopping Detector

The experimental study of interactions between elementary particles ultimately depends on the solution of various methodical problems regarding efficient particle recording. In a number of cases it is required to record positive pions carrying a specified quantity of energy. Over a certain range of pion energy (about 100 MeV) the solution of this problem may be based on the separation of these particles by slowing them to a complete halt and using the fact that the halted pion decays thus: π → µ + ν.