Measurement and Analysis of the Reaction $\gamma \gamma \to \pi^+ \pi^- \pi^+ \pi^-$

The collaboration
Z.Phys.C 38 (1988) 521, 1988.

Abstract (data abstract)
DESY-PETRA. PLUTO Collaboration. Measurement of cross sections for four charged pions in photon-photon collisions for non-tag and single-tag events. Process is dominated by 2RHO0 production with rapid rise in cross section around W = 1.2 GeV. Spin parity analysis of 2RHO0 system shows JP = 2+ to dominate, though 0+ is also possible for W& lt;1.4 GeV. Negative parity states are excluded.