Study of pi(0) pair production in single-tag two-photon collisions

Abstract

We report a measurement of the differential cross section of pi(0) pair production in single-tag two-photon collisions, gamma*gamma -˃ pi(0) pi(0), in e(+) e(-) scattering. The cross section is measured for Q(2) up to 30 GeV2, where Q(2) is the negative of the invariant mass squared of the tagged photon, in the kinematic range 0.5 GeV ˂ W ˂ 2.1 GeV and vertical bar cos theta*vertical bar ˂ 1.0 for the total energy and pion scattering angle, respectively, in the gamma*gamma center-of-mass system. The results are based on a data sample of 759 fb(-1) collected with the Belle detector at the KEKB asymmetric-energy e(+) e(-) collider. The transition form factor of the f(0)(980) and that of the f(2)(1270) with the helicity-0, -1, and -2 components separately are measured for the first time and are compared with theoretical calculations.