The Reaction $\gamma p \to p \pi^+ \pi^- \pi^+ \pi^-$ for Photon Energies From 25-{GeV} to 70-{GeV}

The Bonn-CERN-Ecole Poly-Glasgow-Lancaster-Manchester-Orsay-Paris-Rutherford-Sheffield collaboration Aston, D. ; Atkinson, M. ; Bailey, R. ; et al.
Nucl.Phys.B 189 (1981) 15-39, 1981.
Inspire Record 164533 DOI 10.17182/hepdata.34258

Measurements of the reaction γ p → p π + π − π + π − are presented, in which π + π − π + π − systems with masses up to 3 GeV are produced from fragmentation of the incident photon. The reaction is dominated by production of the large peak of the ϱ′(1600) meson and, at higher masses ≳2 GeV, y production of jet-like 4 π systems. The ϱ′(1600) meson is produced by a predominantly s -channel helicity conserving mechanism. At higher masses there are also indications of ϱπ peaks, of masses 1.3 GeV (the A 2 meson) and 1.75 GeV, produced with a recoiling π meson by a mechanism consistent with the Deck effect.

1 data table

CORRECTED FOR TAILS OF BREIT-WIGNER RESONANCE USED IN FIT AND ALLOWING FOR 10 PCT BACKGROUND.


Observation of the $\rho^-$prime (1600) in the Channel $\gamma p \to \pi^+ \pi^- p$

The Bonn-CERN-Ecole Poly-Glasgow-Lancaster-Manchester-Orsay-Paris-Rutherford-Sheffield collaboration Aston, D. ; Atkinson, M. ; Bailey, R. ; et al.
Phys.Lett.B 92 (1980) 215-218, 1980.
Inspire Record 152747 DOI 10.17182/hepdata.27241

A dipion enhancement of mass 1.59 GeV and width 0.23 GeV is observed in the channel γp→π + π − p. The spin-parity of the enhancement is consistent with being 1 − .

1 data table

No description provided.