Dobado González, AntonioMorales, J.2023-06-202023-06-201996-01-040370-269310.1016/0370-2693(95)01240-0https://hdl.handle.net/20.500.14352/58735© 1996 Elsevier Science B.V.. This work has been supported in part by the Ministerio de Education y Ciencia (Spain) (CICYT AEN93- 0776) and COLCIENCIAS (Colombia). The authors thank F. Cornet, J.F. Donoghue, J. Gasser and J.R. Pelaez for useful information and discussions.In this work we present the results of a complete calculation of the gamma gamma --> pi(0) pi(0) amplitude to leading order in the large N approximation (N being the number of Goldstone bosons) up to order m(pi)(2)/F-2, The amplitude turns to be proportional a to that of pi(+)pi(-) --> pi(0) pi(0). In spite of the fact that this factorization property cannot hold in general (as it was recently pointed our by Morgan and Penington), it appears here since in the large N limit only the I = J = 0 channel contributes to the gamma gamma --> pi(0) pi(0) reaction. Moreover it seems to be a reasonable approximation in this case since it is possible to reproduce, as a prediction, the experimental data starting from a one-parameter fit of the pi pi scattering data.engjournal articlehttp://www.sciencedirect.com/science/article/pii/0370269395012400http://www.sciencedirect.comhttp://arxiv.org/abs/hep-ph/9511244open access53Perturbation-TheoryCollisionsResonancesAmplitudeSectorFísica (Física)22 Física