Extracting the f0(980) signal from the photoproduced π+ π- spectrum

We present a phenomenological analysis of the π + π - photoproduction data obtained by the CLAS collaboration at the Thomas Jefferson Laboratory. A special emphasis is put on the interference pattern observed in the moments of angular distribution for the π + π - efective masses around 1 GeV. This pattern is attributed to the photoproduction of the scalar-isoscalar resonance f 0 (980). By fitting the model parameters to the data we obtain the strengths of the resonant and nonresonant parts of the S-wave photoproduction amplitude. We calculate the f 0 (980) photoproduction cross section which is smaller than previous estimations by a factor of about 5. A new estimation of the product of the σ meson couplings to nucleon and to the γρ system | g NNσ g γρσ | is given.