1. Evidence for ϱ1(1270) production in the reaction K−p → π+π−Λ
- Author
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D.C. Schultz, D. Aston, F. Bird, W.B. Johnson, L. Levinson, T. Shimomura, P.K. Sinervo, S. L. Shapiro, P.E. Rensing, Yeong-Dae Kwon, T. Tauchi, G. Tarnopolsky, C.O. Pak, T. Bienz, N. Awaji, A. P. Waite, D. W. G. S. Leith, S. Iwata, W. Dunwoodie, J. D'Amore, Shiro Suzuki, T. Matsui, S. H. Williams, N. Toge, H. Hayashii, B. N. Ratcliff, Kumataro Ukai, H. Ozaki, P. Kunz, A. Sugiyama, R. Endorf, B. T. Meadows, K. Fujii, J. Martinez, M. Nussbaum, A. Miyamoto, and R. Kajikawa
- Subjects
Nuclear and High Energy Physics ,Amplitude ,Spectrometer ,Mass distribution ,Branching fraction ,Chemistry ,Dalitz plot ,Parity (physics) ,Atomic physics ,Atomic and Molecular Physics, and Optics ,Excitation - Abstract
Preliminary results are presented from an analysis of the π+π− system produced in the reaction K−p → π+π−Λ at 11 GeV/c observed with the LASS spectrometer at SLAC. A clear ϱ - ω interference effect is observed, and a fit to the natural parity exchange mass distribution yields a branching fraction estimate of (1.7 ± 0.5) % for the decay ω → π+π−. An amplitude analysis reveals that the bump in the mass distribution in the vicinity of the ƒ2(1270) actually contains a significant P-wave component. The mass dependence of the corresponding amplitude and phase is well described by a resonant Breit-Wigner line-shape with mass (1266 ± 14) MeV/c2, width (166 ± 35) MeV/c2, and estimated elasticity ∼ 5%. The interpretation of this state as the first radial excitation of the ϱ(770) is discussed.
- Published
- 1991
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