1997/07/28 by M. Svec, Svec, M.
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #hep-ph
paper · pdf · doi:10.48550/arxiv.hep-ph/9707495
47 pages, 13 Figures
arxiv created 1997/07/28 · arxiv updated 2009/11/30
We have performed a new model independent amplitude analysis of reaction π- p → π- π+ n measured at CERN at 17.2 GeV/c on polarized target. The analysis extends the range of dipion mass from 600--880 MeV used in the previous study to 580--1080 MeV. Our purpose is to study the role of f0(980) interference and to better determine the resonance parameters of σ(750) resonance from fits to both S-wave amplitudes | S|2Σ and |S|2Σ with recoil nucleon transversities ``up'' and ``down'', respectively. This work is the first attempt to determine resonance parameters of a resonance from Breit-Wigner fits to production amplitudes of opposite transversity. We used several fitting procedures to understand the resonant structure of the S-wave amplitudes in this mass range. The simultaneous fit to | S|2Σ and |S|2Σ with two common σ poles yields an excellent fit with a lower χ2/dpt than the separate fits. All amplitudes are dominated by a σ state with mσ= 786 ± 24 MeV and Γσ= 130± 47 MeV. All amplitudes receive a weaker contribution from a narrower σ' state with mσ' = 670 ± 30 MeV and Γσ' = 59 ± 58 MeV. We propose to identify σ'(670) and σ(786) with colour-electric and colour-magnetic modes of lowest mass scalar gluonium 0++ (gg).