Measurement of the eta and eta(') transition form factors at q(2)=112 GeV2

We report a study of the processes e(+)e(-)->eta gamma and e(+)e(-)->eta(')gamma at a center-of-mass energy of 10.58 GeV, using a 232 fb(-1) data sample collected with the BABAR detector at the PEP-II collider at SLAC. We observe 20(-5)(+6)eta gamma and 50(-7)(+8)eta(')gamma events over small backgrounds, and measure the cross sections sigma(e(+)e(-)->eta gamma)=4.5(-1.1)(+1.2)+/- 0.3 fb and sigma(e(+)e(-)->eta(')gamma)=5.4 +/- 0.8 +/- 0.3 fb. The corresponding transition form factors at q(2)=112 GeV2 are q(2)vertical bar F-eta(q(2))vertical bar=0.229 +/- 0.030 +/- 0.008 GeV, and q(2)vertical bar F-eta(')(q(2))vertical bar=0.251 +/- 0.019 +/- 0.008 GeV, respectively.