ISSN - 00319015, Journal of the Physical Society of Japan, 2007, vol. 76, p. -
High statistics measurement of the cross sections of γγ → π +π - production
We report on a high statistics measurement of the total and differential cross sections of the process γγ → π +π - in the π +π - invariant mass range 0.8 GeV/c 2 < W < 1.5 GeV/c 2 with 85.9 fb -1 of data collected at √s = 10.58 GeV and 10.52 GeV with the Belle detector. A clear signal of the f 0(980) resonance is observed in addition to the f 2(1270) resonance. An improved 90% confidence level upper limit ℬ(η′(958) → π +π - < 2.9 × 10 -3 is obtained for P- and CP-violating decay of the η′(958) meson using the most conservative assumption about the interference with the background. ©2007 The Physical Society of Japan.