High statistics study of f_0(980) resonance in gamma gamma --> pi^+ pi^-   production
  We report on a high statistics measurement of the cross section of the process gamma gamma to pi^+ pi^- in the center-of-mass energy range 0.8 GeV/c^2 < W < 1.5 GeV/c^2 with 85.9 fb^-1 of data collected at sqrt(s)=10.58 GeV and 10.52 GeV with the Belle detector. A clear signal for the f_0 lr 980 resonance is observed. From a fit to the mass spectrum, the resonance's mass, pi^+ pi^- and two-photon decay widths are found to be 985.6^+1.2 _-1.5(stat)^+1.1_-1.6(syst) MeV/c^2, 34.2^+13.9_-11.8(stat)^+8.8_-2.5(syst) MeV, and 205^+95_-83(stat)^+147_-117(syst) eV, respectively. 
The Belle Collaboration: K. Abe, et al