Photoproduction of $\pi^+ \pi^- \pi^0$ on Hydrogen With Linearly Polarized Photons of Energy 20-{GeV} - 70-{GeV}

The Omega Photon & Bonn-CERN-Glasgow-Lancaster-Manchester-Paris-Rutherford-Sheffield collaborations Atkinson, M. ; Axon, T.J. ; Barberis, D. ; et al.
Nucl.Phys.B 231 (1984) 15-39, 1984.
Inspire Record 191169 DOI 10.17182/hepdata.33892

Results on photoproduction of π + π − π 0 in the photon energy range 20–70 GeV are presented. For the ω meson, the production cross-section is found to be 1010±15 (statistical)±290 (systematic) nb and is constant over the incident photon energy range. Spin-density matrix elements are evaluated for ω meson production. The φ meson is observed with a total photoproduction cross section (corrected for branching ratio to π + π − π 0 ) of 610±35±170 nb. A third resonance, at 1.67 GeV, is seen in the mass spectrum and its interpretation is discussed. The production of a broad π + π − π 0 continuum, mainly via ϱπ, and peaking at 1.2 GeV, contributes with a cross section of about 2.5 ωb. The spin-parity content is analysed by the moments of the π + π − π 0 decay angular distribution in the helicity frame and by maximum likelihood fits to the π + π − π 0 Dalitz plot. It is found that production of J P = 1 − states accounts for less than half of the total mass spectrum above 900 MeV. There is a broad enhancement in the 1 + wave around 1.15 GeV indicating photoproduction of the H(1190) meson.

6 data tables

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EXPONENTIAL FITS TO D(SIG)/DT IN OMEGA MASS REGION.

EXPONENTIAL FITS TO D(SIG)/DT OVER FULL ENERGY FOR THREE MASS REGIONS CORRESPONDING TO OMEGA, PHI AND OMEGA*.

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