Measurement of the pi- p ---> n pi0 and pi- p ---> n gamma differential cross-sections near the resonance p(11)(1460)

Cheze, J.B. , Codreanu, N. , Hamel, J.L. , Le Calvez, O. , Teiger, J. , Thevenet, B. , Zaccone, H. , Zsembery, J.
Nucl.Phys.B 72 (1974) 365-375, 1974.

Abstract (data abstract)
THE FOLLOWING COMMENTS ARE TAKEN FROM THE PI N COMPILATION OF R.L. KELLY. THEY ARE THAT COMPILATION& apos;S COMPLETE SET OF COMMENTS FOR PAPERS RELATED TO THE SAME EXPERIMENT (DESIGNATED CHEZE74) AS THE CURRENT PAPER. (THE IDENTIFIER PRECEDING THE REFERENCE AND COMMENT FOR EACH PAPER IS FOR CROSS-REFERENCING WITHIN THESE COMMENTS ONLY AND DOES NOT NECESSARILY AGREE WITH THE SHORT CODE USED ELSEWHERE IN THE PRESENT COMPILATION.) /// CHEZE74 [J. B. CHEZE,NP B72,365(1974)] -- MEASUREMENT OF PI- P CEX DCS AND PI- P TO N GAMMA DCS NEAR THE BACKWARD DIRECTION AT 475 AND 550 MEV/C. DONE AT SATURNE USING NEUTRON COUNTERS AND GAMMA DETECTION IN AN OPTICAL SPARK CHAMBER. THE SUMMED DCS FOR THE 2 REACTIONS IS OBTAINED FROM THE NEUTRON TRIGGERS, AND THE REACTIONS ARE THEN SEPERATED STATISTICALLY USING THE GAMMA ANGULAR DISTRIBUTION RELATIVE TO THE NEUTRON DIRECTION. THE N GAMMA/CEX RATIO AND THE N GAMMA DCS AT EACH ANGLE ARE TABULATED,AND THE SUMMED DCS AND CEX DCS ARE PLOTTED. WE HAVE RECONSTRUCTED THE CEX DCS FROM THE TABLE TREATING THE RATIO AND THE N GAMMA DCS AS STATISTICALLY INDEPENDENT. THIS PROCEDURE OVERESTIMATES THE STATISTICAL ERRORS (SINCE IT GIVES THE ERROR OF THE RATIO MUCH MORE WEIGHT THAN IT WOULD HAVE IN A REALISTIC ESTIMATE) AND GIVES MUCH LARGER ERRORS (ABOUT +/- 30 PCT) THAN IN THE GRAPHS OF THE SUMMED DCS AND CEX DCS. HOWEVER,IN VIEW OF THE LACK OF NEUTRON COUNTER EFFICIENCY MEASUREMENTS,THE LACK OF A CONSTRAINED FIT ANALYSIS OF THE EVENTS,AND THE LARGE ANGULAR BINS OVER WHICH THE CEX DCS IS AVERAGED, A +/- 30 PCT ERROR IS NOT UNREALISTIC AND WE HAVE KEPT THESE LARGE ERRORS. AT TWO POINTS (MOST BACKWARD POINTS AT 550 MEV/C) WHERE THE RATIO IS LARGE AND THE ERRORS CORRESPONDINGLY SMALL WE HAVE INCREASED THE ERRORS.

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