Production and neutral decay of the eta meson in pi- p collisions
1970
10 pages
Published in:
- Phys.Rev.D 1 (1970) 10-19
Citations per year
Abstract: (APS)
The reaction π−p→ηn has been observed through the decay mode η→2γ at Tπ−=592, 655, 704, 875, 975, 1117, and 1300 MeV. The detection apparatus was a cubic array of six steel-plate optical spark chambers that completely surrounded a liquid-hydrogen target. We identified events attributed to the decay of an η by the large c.m. opening angle between the two showers generated in the steel plates by the decay photons. We have calculated the total cross section for η production, which is proportional to the number of events under the large-angle peak in the opening-angle distribution. The total cross section rises steeply from threshold to a maximum of about 2.4 mb at 650 MeV, and then falls gradually to about 0.66 mb at 1300 MeV. The differential cross section was obtained by taking the coefficients of a Legendre-polynomial fit to the angular distribution of bisectors of selected two-shower events, and converting them to the coefficients of the η c.m. angular distribution. The differential cross section is found to be isotropic at 592 MeV, to require terms through P2(cosθη) between 655 and 975 MeV, and to have a forward peak fitted by terms through P3(cosθη) at 1117 MeV and through P4(cosθη) at 1300 MeV. It is suggested that production at threshold is predominantly through an S state, with some P1 and D3 waves entering by 655 MeV. We suggest that all the absorption in the S11 πN state can be explained by the η production.- pi- p: interaction
- interaction: pi- p
- eta(549): production
- production: eta(549)
- eta(549): decay
- decay: eta(549)
- final state
- 2photon
- pi-: total cross section
- total cross section: pi-
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