Accession Number : AD0637734

Title :   STUDY OF PI(+) 2 PI(-) FINAL STATES COHERENTLY PRODUCED ON NUCLEI BY 16 GEV/C PI(-).

Descriptive Note : Final technical rept.

Corporate Author : CALIFORNIA UNIV BERKELEY COSMIC RAY GROUP

Personal Author(s) : Allard,J. F. ; Drijard,D. ; Hennessy,J. ; Huson,R. ; Lloret,A.

Report Date : AUG 1966

Pagination or Media Count : 25

Abstract : Coherent production of pi(+) 2pi(-) occurs in approx. 1% of 15 and 16 GeV/c pi(-) C2F5C1 interactions (studied in the Ecole Polytechnique HLBC exposed at the CERN P.S.). For nearly every coherent event, one or both pi(+) pi(-) combinations lies in the rho(o) or f(o). The ratio of pi(-) f(o) to pi(-) rho o coherent production is 0.05 plus or minus 0.02. No N(*) peaks are seen in the coherent events. S-wave pi(-) rho(o) (J(P) = 1(+)) dominates up to at least 1.2 GeV in M pi(-) rho(o) but small admixture of waves of opposite parity is necessary to explain some angular distribution asymmetries. The Dalitz plot excludes dominance of triangle singularity effects. The pi(-) rho(o) mass distribution is dominated by a peak in the A sub 1 region, nearly 250 MeV wide, but too narrow to be explained by the momentum transfer limitation imposed by the nuclear form factor. The calculated OPE (Deck model) and rho exchange M sub pi rho distributions are also too broad to fit out data, but uncertainties in the model preclude its firm rejection. If M sub pi rho distribution is assumed due entirely to resonances, there must be one dominant J(P) = 1(+) resonance near 1.05 GeV. To preserve the A sub 1 with width <150 MeV one must assume two other resonances (approx 940 and approx 1180 MeV) in addition to the A sub 2 (1315). (Author)

Descriptors :   (*MESONS, NUCLEAR REACTIONS), COHERENT SCATTERING, INELASTIC SCATTERING, BUBBLE CHAMBERS, PIONS, NUCLEAR PHYSICS, FRANCE

Subject Categories : Nuclear Physics & Elementary Particle Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE