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Title: Evidence for a scalar state I =0 0 sup ++ (750) from measurements of. pi. N sub up arrow r arrow. pi. sup +. pi. sup minus N on a polarized target at 5. 98, 11. 85, and 17. 2 GeV/ c

Journal Article · · Physical Review, D (Particles Fields); (United States)
 [1]; ;  [2]
  1. Physics Department, Dawson College, Montreal, Quebec, H3Z 1A4 (Canada) McGill University, Montreal, Quebec, H3A 2T8 (Canada)
  2. Departement de Physique des Particules Elementaires, Centre d'Etudes Nucleaires, Saclay, 91191 Gif-sur-Yvette (France)

Measurements 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} enable model-independent amplitude analyses which yield two solutions for moduli and cosines of certain relative phases of the two {ital S}-wave and six {ital P}-wave production amplitudes describing the pion production process below the dipion mass of 1000 MeV. We obtain four solutions for the {ital S}- and {ital P}-wave intensities in the physical region of the {pi}{ital N}{r arrow}{pi}{sup +}{pi}{sup {minus}}{ital N} reaction. The results for the {ital S}-wave intensity provide solution-independent evidence for a new resonant state {ital I}=0 0{sup ++}(750). Its {pi}{sup +}{pi}{sup {minus}} decay width depends on the solution and is estimated to be in the range of 100--250 MeV. The {ital I}=0 0{sup ++}(750) meson is best understood as the lowest-mass scalar gluonium 0{sup ++}({ital gg}). Our results emphasize the need for a systematic study of pion production on the level of amplitudes in a new generation of dedicated experiments with spin at the recently proposed high-intensity hadron facilities.

OSTI ID:
7287086
Journal Information:
Physical Review, D (Particles Fields); (United States), Vol. 46:3; ISSN 0556-2821
Country of Publication:
United States
Language:
English