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Study of {sigma}(750) and {rho}{sup 0}(770) production in measurements of {pi}{ital N}{sub {up_arrow}}{r_arrow}{pi}{sup +}{pi}{sup {minus}}{ital N} on a polarized target at 5.98, 11.85, and 17.2 GeV/{ital c}

Journal Article · · Physical Review, D
 [1]
  1. Physics Department, Dawson College, Montreal, Quebec, H3Z 1A4 (CANADA)
We present a new and improved model-independent amplitude analysis of the reactions {pi}{sup +}{ital n}{sub {up_arrow}}{r_arrow}{pi}{sup +}{pi}{sup {minus}}{ital p} at 5.98 and 11.85 GeV/{ital c} and {pi}{sup {minus}}{ital p}{sub {up_arrow}}{r_arrow}{pi}{sup {minus}}{pi}{sup +}{ital n} at 17.2 GeV/{ital c} measured with transversely polarized targets at the CERN Proton Synchrotron. For dipion masses below 1000 MeV the pion production process is described by two {ital S}-wave and six {ital P}-wave production amplitudes. Previous analyses suffered from the presence of unphysical solutions for moduli of amplitudes or cosines of their relative phases, causing uncertainties regarding the signal for the scalar state {ital I}=0 0{sup ++}(750). To remove the unphysical solutions we use a Monte Carlo approach to amplitude analysis. In each ({ital m},{ital t}) bin we randomly varied the input spin-density-matrix elements 30000 times within their experimental errors and performed an amplitude analysis for each selection. Unphysical solutions were rejected and the physical solutions produced a continuous range of values for moduli, cosines of relative phases, and for partial wave intensities. A clear signal for {sigma}(750) resonance emerges in all four solutions for an {ital S}-wave intensity {ital I}{sub {ital S}} at 5.98 and 11.85 GeV/{ital c} and in both solutions for an {ital S}-wave amplitude {parallel}{bar {ital S}}{parallel}{sup 2}{Sigma} at 17.2 GeV/{ital c}. Its {pi}{sup +}{pi}{sup {minus}} decay width is estimated to be in the range 200{endash}300 MeV. We find a significant suppression of {rho}{sup 0} production in the amplitudes {parallel}{ital U}{parallel}{sup 2}{Sigma}, {parallel}{bar {ital N}}{parallel}{sup 2}{Sigma} and at 17.2 GeV/{ital c} in {parallel}{ital L}{parallel}{sup 2}{Sigma}. (Abstract Truncated)
OSTI ID:
279159
Journal Information:
Physical Review, D, Journal Name: Physical Review, D Journal Issue: 5 Vol. 53; ISSN PRVDAQ; ISSN 0556-2821
Country of Publication:
United States
Language:
English