First observation of the reaction gamma gamma ---> pi (2) ---> pi0 pi0 pi0

The Crystal Ball collaboration Antreasyan, D. ; Bartels, H.W. ; Besset, D. ; et al.
Z.Phys.C 48 (1990) 561-568, 1990.
Inspire Record 296523 DOI 10.17182/hepdata.15136

The Crystal Ball detector has been used at the DORIS II storage ring at DESY to study the reactionγγ→π0π0π0 in theπ0π0π0 invariant mass range from 850 MeV/c2 to 2600 MeV/c2. An enhancement around 1750 MeV/c2 is attributed to theπ2(1670) resonance. The observedπ0π0 invariant mass distribution and theπ0 angular distributions are consistent with those expected for the decay chainπ2→π0f2(1270)→π0π0π0. From our measurements we find the following resonance parameters: two photon partial width\(\Gamma _{\pi _2 }^{\gamma \gamma }= (1.41 \pm 0.23 \pm 0.28)keV\), massM(π2)=(1742±31±49)MeV/c2. and total width\(\Gamma _{\pi _2 }^{tot}= (236 \pm 49 \pm 36)MeV\).

2 data tables

Data read from graph.

Cross section times branching ratio to 3pi0 assuming the decay chain pi2 --> pi0f2 --> 3pi0.