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Measurement of the left-right asymmetry in pion-proton radiative exchange and charge exchange scattering from 301 to 625 MeV/c on a transversely polarized target [electronic resource].

Published
Los Alamos, N.M. : Los Alamos National Laboratory, 1988.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Physical Description
Pages: 151 : digital, PDF file
Additional Creators
Los Alamos National Laboratory and United States. Department of Energy. Office of Scientific and Technical Information
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Summary
The left-right asymmetry A/sub N/ in ..pi../sup /minus//p ..-->.. ..gamma..n has been measured at p/sub ..pi.. = 301, 316, 427, 471, 547, 586, and 625 MeV/c using a transversely polarized target. The final-state neutron and gamma were detected in coincidence by two states of matching neutron and gamma detectors at gamma angles centered around 90/degree and 110/degree/ c.m. A gamma detector consisted of an array of 15 counters, each was 15/times/15/times/25 cm/sup 3/ block of lead-glass. A neutron detector consisted of 15 counters also, each one was a cylindrical plastic scintillator 7.6 cm in diameter and 45.7 cm long. The A/sub N/ results are compared with the predictions from the most recent single-pion photoproduction partial-wave analysis by Arai and Fujii. The agreement is poor, casting doubt on the correctness of the value for the radiative-decay amplitude of the neutral Roper resonance now in use. A comparison is made with the 90/degree/recoil proton polarization data of the inverse reaction derived from ..gamma..d scattering, there are substantial discrepencies. Charge exchange (..pi../sup /minus/p/ ..-->.. ..gamma../degree/n) events were the major yield in this experiment. Very precise values of the charge exchange analyzing power were obtained with an error of typically 3%. The charge exchange results are compared with the predictions from recent ..gamma..n partial wave analyses. At the lower incident energies little difference is seen between the VPI, Karlsruhe-Helsinki, and CMU-LBL analyses, and there is excellent agreement with our experiment. From the onset of the Roper resonance the VPI solution is strongly favored.
Report Numbers
E 1.99:la-11273-t
la-11273-t
Subject(s)
Other Subject(s)
Note
Published through SciTech Connect.
05/01/1988.
"la-11273-t"
"DE88009808"
Kim, George Jung-Kwang.
Funding Information
W-7405-ENG-36
View MARC record | catkey: 14715497