Reaction γγ→ππ: the (IJPC=00++)-wave spectra at Eγγ(c.m.)∼300–1900 MeV

Abstract We calculate the 00 ++ -wave spectra for the reactions γγ → π 0 π 0 and γγ → π + π − on the basis of: (i) the results of the K -matrix analysis of the 00 ++ amplitudes for the reactions ππ → ππ , K K , ηη , ηη ′, ππππ , and (ii) recently developed method for calculation of the decay amplitudes f 0 (1 3 P 0 q q )→γγ , f 0 (2 3 P 0 q q )→γγ . The reconstructed π 0 π 0 and π + π − spectra can be used as a guide for the extraction of partial widths of scalar/isoscalar resonances f 0 (980)→ γγ , f 0 (1300)→ γγ , f 0 (1500)→ γγ , f 0 (1750)→ γγ . As follows from our calculations, the resonances f 0 (980) and f 0 (1500) in the π + π − and π 0 π 0 spectra reveal themselves as dips.