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Matrix element of the reaction. pi. /sup -/p. --> pi. /sup 0/. pi. /sup 0/n near threshold

Journal Article · · Sov. J. Nucl. Phys. (Engl. Transl.); (United States)
OSTI ID:6375831
We obtain a phenomenological matrix element that makes it possible to describe the spectra of the ..gamma.. quanta from the reaction ..pi../sup -/p..--> pi../sup 0/..pi../sup 0/n near threshold. The matrix element takes the form M/sup 2/=)1+A (p*/sub ..pi..-/p*)) )/sup 2/+B((p*/sub ..pi../sup 01// - ..beta..*/sub ..pi../sup 02//) p*/sub ..pi../sup 02// p*/sub n/)/sup 2/ an energy 270 MeV, where A=0.5m/sub ..pi..//sup -2/ and B=3m/sub ..pi..//sup -4/. The registration efficiency of the ..gamma.. quanta from the reaction ..pi../sup -/p..--> pi../sup 0/..pi../sup 0/n, calculated with the new matrix element, agrees with the counts obtained with Cerenkov counters in a different geometry. The total cross section of this reaction at 270 MeV is 0.26 +- 0.02 mb. An isotopic analysis of the reactions ..pi..Nreverse arrow..pi pi..N was performed at this energy. The ratio X=F/sub 10//F/sub 32/ of the isotopic amplitudes is 4.4 +- 0.4.
Research Organization:
Joint Institute for Nuclear Research
OSTI ID:
6375831
Journal Information:
Sov. J. Nucl. Phys. (Engl. Transl.); (United States), Journal Name: Sov. J. Nucl. Phys. (Engl. Transl.); (United States) Vol. 28:5; ISSN SJNCA
Country of Publication:
United States
Language:
English