Study of resonant structure of S-wave amplitudes in pi(-)p->pi(-)pi(+)n measured on polarized target at 17.2 GeV/c in the mass range of 580-1080 MeV

Abstract

We have performed a new model independent amplitude analysis of reaction $\ddot{I}{€}^{-}p\to \ddot{I}{€}^{-}\ddot{I}{€}^{+}n$ 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 $f_0(980)$ interference and to better determine the resonance parameters of $\ddot{I}ƒ(750)$ resonance from fits to both S-wave amplitudes $|\bar{S}{|}^2\hat{I}\pounds$ and $|S{|}^2\hat{I}\pounds$ 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 $|\bar{S}{|}^2\hat{I}\pounds$ and $|S{|}^2\hat{I}\pounds$ with two common $\ddot{I}ƒ$ poles yields an excellent fit with a lower $\ddot{I}{‡}^2/dpt$ than the separate fits. All amplitudes are dominated by a $\ddot{I}ƒ$ state with $m_{\ddot{I}}ƒ=786\pm 24$ MeV and $\hat{I}{“}_{\ddot{I}}ƒ=130\pm 47$ MeV. All amplitudes receive a weaker contribution from a narrower $\ddot{I}{ƒ}^{\prime }$ state with $m_{\ddot{I}{ƒ}^{\prime }}=670\pm 30$ MeV and $\hat{I}{“}_{\ddot{I}{ƒ}^{\prime }}=59\pm 58$ MeV. We propose to identify $\ddot{I}{ƒ}^{\prime }(670)$ and $\ddot{I}ƒ(786)$ with colour-electric and colour-magnetic modes of lowest mass scalar gluonium $0^{++}(gg)$.

47 pages, 13 Figures