DOI: 10.17182/hepdata.5293.v1/t2
title: "Table 2" of "Charge exchange and production of eta mesons and multiple neutral pions in pi- p reactions between 654 and 1247 mev/c"

description: No description provided.
description: ALL DATA IN THIS RECORD ARE REDUNDANT. I.E., THEY WERE OBTAINED DIRECTLY FROM OTHER DATA IN THIS FILE, USUALLY BY EXTRAPOLATION OR INTEGRATION.. 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 BULOS69) 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.) /// BULOS64 [F. BULOS,PRL 13,558(1964)] -- /// BULOS69 [F. BULOS,PR 187,1827(1969)] -- PI- P CEX DCS FROM A TOTAL OF 81K EVENTS AT 11 MOMENTA BETWEEN 654 AND 1247 MEV/C. DONE AT COSMOTRON WITH GAMMA DETECTION IN STEEL PLATE OPTICAL SPARK CHAMBERS SUBTENDING (2/3)*(4*PI) STERADIANS AT THE TARGET. THE ANGULAR DISTRIBUTIONS ARE REPORTED AS LEGENDRE COEFFICIENTS WITH FULL ERROR MATRICES. AT EACH ENERGY WE HAVE RECONSTRUCTED A NUMBER OF CROSS SECTION POINTS EQUAL TO THE NUMBER OF REPORTED LEGENDRE COEFFICIENTS AND RECORDED THESE CROSS SECTIONS USING THE SQUARE ROOTS OF THE DIAGONAL ELEMENTS OF THEIR ERROR MATRIX FOR ERRORS AND NEGLECTING THE OFF DIAGONAL ELEMENTS OF THEIR ERROR MATRIX. THE COS(THETA) VALUES FOR THE RECONSTRUCTED DATA POINTS WERE CHOSEN TO MINIMIZE THE SUM OF SQUARES OF OFF DIAGONAL ELEMENTS OF THEIR CORRELATION MATRIX. THE SQUARE ROOT OF TWICE THIS QUANTITY IS THE RMS ERROR IN CHISQ RESULTING FROM NEGLECT OF CORRELATIONS BETWEEN THE RECONSTRUCTED VALUES IN A FIT. EXCEPT AT 1099 MEV/C (SEE BELOW) NO NEGLECTED CORRELATION COEFFICIENT WAS AS LARGE AS 0.1 (MOST WERE CONSIDERABLY SMALLER),AND THE RMS CHISQ ERROR RANGED BETWEEN 0.32 AND 0.51. AT 1099 MEV/C THERE ARE EVIDENTLY MISPRINTS IN THE LEGENDRE COEFFICIENT ERROR MATRIX (LCEM) AS SEVERAL OF ITS OFF DIAGONAL ELEMENTS ARE NOT SYMMETRIC. THE RECONSTRUCTED CROSS SECTION DATA HAS CORRELATION COEFFICIENTS AS LARGE AS 0.26,AND THE RMS CHISQ ERROR FROM NEGLECT OF CORRELATIONS IS 1.6. ALSO,THE TABULATED LEGENDRE COEFFICIENTS AT 1099 MEV/C DISAGREE WITH THOSE IN AN ACCOMPANYING GRAPH (THERE ARE ALSO A NUMBER OF SMALLER DISCREPANCIES AT OTHER ENERGIES WHICH WE HAVE IGNORED). ACCORDINGLY,WE HAVE RECONSTRUCTED THE CROSS SECTION AT 1099 MEV/C USING BOTH THE TABLE AND THE GRAPH,AVERAGED THE RESULTS,AND ASSIGNED AN ERROR BY COMBINING IN QUADRATURE THE DIFFERENCE OF THE RESULTS AND THE ERROR COMING FROM THE LCEM. BULOS69 ALSO TABULATES INTEGRATED CEX CROSS SECTIONS,AND THE DCS AT 0 AND 180 DEGREES. IT IS STATED THAT THE ERRORS ON THE DCS POINTS AT 0 AND 180 DEGREES INCLUDE NORMALIZATION ERRORS AS WELL AS THE STATISTICAL ERRORS COMING FROM THE LCEM. COMPARISON WITH ERRORS CALCULATED FROM THE LCEM INDICATES THAT THIS IS ACTUALLY ONLY TRUE AT 0 DEGREES,AND THE NORMALIZATION ERRORS HAVE BEEN UNFOLDED ACCORDINGLY FROM THE 0 DEGREE DATA. AT 1247 MEV/C THE REPORTED ERROR ON THE FORWARD POINT IS SMALLER THAN THAT CALCULATED FROM THE LCEM AND WE HAVE ASSIGNED THIS DATA A 5 PCT NORMALIZATION ERROR (THE MAXIMUM VALUE THAT OCCURED AT THE OTHER ENERGIES). THERE ARE A NUMBER OF DISCREPANCIES BETWEEN THE TABULATED VALUES OF THE INTEGRATED,0 DEGREE,AND 180 DEGREE CROSS SECTIONS AND THE VALUES FOLLOWING FROM THE TABULATED LEGENDRE COEFFICIENTS. WE HAVE IGNORED THESE EXCEPT AT 1099 MEV/C WHERE THE TABULATED VALUES ARE INTERMEDIATE BETWEEN THOSE RECONSTRUCTED FROM THE TABLE AND THE GRAPH. AT THIS ENERGY WE HAVE RECORDED THE TABULATED VALUES,BUT INCREASED THE TABULATED ERRORS AS DESCRIBED ABOVE FOR THE ANGULAR DISTRIBUTIONS. /// COMMENTS ON MODIFICATIONS TO LOVELACE71 COMPILATION BY KELLY -- LOVELACE71 RECORDS THE LEGENDRE COEFFICIENTS OF BULOS69 WITH INDIVIDUAL ERRORS ONLY.