ISSN:
1434-6052
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract We present an analysis ofρ 0 ρ 0 production by two photons in theρ 0 ρ 0 invariant mass range from 1.2 to 2.0 GeV. From a study of the angular correlations in the process γγ→ρ 0 ρ 0→π−π+π− we exclude a dominant contribution fromJ P=0− or 2− states. The data indicate sizeable contributions fromJ P=0+ for four pion massesM 4π〈1.7 GeV and fromJ P=2+ forM 4π〉1.7 GeV. The data are also well described by a model with isotropic production and uncorrelated isotropic decay of theρ 0,s. The cross section stays high below the nominalρ 0 ρ 0 threshold, i.e.M 4π〈1.5 GeV. The matrix element forρ 0 ρ 0 production is found to decrease steeply with increasingM 4π. Upper limits for the couplings of the ι(1440) and Θ(1640) to γγ andρ 0 ρ 0 are given:Γ(ι→γγ)·B(ι→ρ 0 ρ 0)〈1.0 keV andΓ(Θ→γγ)
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01573742