ENTRY C2609 20210510 C205C260900000001 SUBENT C2609001 20210510 C205C260900100001 BIB 10 31 C260900100002 TITLE Ordinary and Exchange Scattering of Negative Pions by C260900100003 Hydrogen C260900100004 AUTHOR (E.Fermi,H.L.Anderson,A.Lundby,D.E.Nagle,G.B.Yodh) C260900100005 REFERENCE (J,PR,85,935,1952) C260900100006 #doi:10.1103/PhysRev.85.935 C260900100007 INSTITUTE (1USACHI) C260900100008 FACILITY (SYNCY,1USACHI) The large Chicago cyclotron. C260900100009 DETECTOR (SCIN) The two scintillators had diameters 4 inches C260900100010 and 3 inches and were placed, respectively, 8 inches C260900100011 and 11 inches below the center of the scattering C260900100012 chamber. C260900100013 SAMPLE Liquid hydrogen. C260900100014 METHOD (COINC) The beam of pions enters the experimental C260900100015 space and is deflected by an analyzing magnet. After C260900100016 this, it is recorded by the coincidences of two C260900100017 1-inch-square crystals and falls on the liquid C260900100018 hydrogen scattering chamber. The scattered products C260900100019 are observed by quadruple coincidences of these two C260900100020 counters with another pair of scintillators located C260900100021 directly under the scattering chamber in a direction C260900100022 at 90 degrees to that of the incident pions. In order C260900100023 to increase the sensitivity of the scattering C260900100024 detectors to gamma-rays, a lead radiator 1/4 inch C260900100025 thick was interposed in front of the third counter. A C260900100026 standard measurement involved the observation of the C260900100027 ratio between scattered and incident particles with C260900100028 and without hydrogen in the scattering chamber, and C260900100029 with and without the lead converter of the C260900100030 gamma radiation. C260900100031 ERR-ANALYS (DATA-ERR) No details on sources of uncertainties. C260900100032 HISTORY (20210510C) BP C260900100033 ENDBIB 31 0 C260900100034 COMMON 1 3 C260900100035 EN C260900100036 MEV C260900100037 118.0 C260900100038 ENDCOMMON 3 0 C260900100039 ENDSUBENT 38 0 C260900199999 SUBENT C2609002 20210510 C205C260900200001 BIB 3 11 C260900200002 REACTION (1-H-1(PIN,PI0)0-NN-1,,SIG) C260900200003 ANALYSIS The conversion to a scattering cross section depends C260900200004 on the assumptions made as to the angular C260900200005 distribution. It also depends on the assumption that C260900200006 me have made in this paper that all neutral pions C260900200007 decay immediately into two photons. For example, if C260900200008 we assume that the angular distribution is fairly C260900200009 isotropic in the center-of-mass system and that the C260900200010 gamma-rays are produced in pairs by the decay of the C260900200011 neutral pions. C260900200012 STATUS (TABLE) page 936. C260900200013 ENDBIB 11 0 C260900200014 NOCOMMON 0 0 C260900200015 DATA 2 1 C260900200016 DATA DATA-ERR C260900200017 MB MB C260900200018 20.0 5.0 C260900200019 ENDDATA 3 0 C260900200020 ENDSUBENT 19 0 C260900299999 SUBENT C2609003 20210510 C205C260900300001 BIB 4 7 C260900300002 REACTION (1-H-1(PIN,G)0-NN-1,,SIG) C260900300003 ANALYSIS The cross section obtained for the charge exchange C260900300004 process is not very sensitive to the angular C260900300005 distribution adopted. C260900300006 FLAG (1.) cosine theta**2 gamma-ray distribution. C260900300007 (2.) sine theta**2 gamma-ray distribution. C260900300008 STATUS (TABLE) page 936. C260900300009 ENDBIB 7 0 C260900300010 NOCOMMON 0 0 C260900300011 DATA 3 2 C260900300012 DATA DATA-ERR FLAG C260900300013 MB MB NO-DIM C260900300014 29.0 7.0 1. C260900300015 18.0 4.0 2. C260900300016 ENDDATA 4 0 C260900300017 ENDSUBENT 16 0 C260900399999 ENDENTRY 3 0 C260999999999