Book Description
In this memo the authors address the following questions: how the [pi]°[gamma] cross section, which is measured in E760, compares to the expected leakage from the [pi]°[pi]° final states; is it possible to affirm that a substantial fraction of the [pi]°[gamma] events are due to continuum production? Naively, the expected continuum [pi]°[gamma] cross section can be estimated using the Vector Meson Dominance Model (VDM). In that framework, a photon is coupled to a neutral vector meson V by G{sub [gamma]V}. Then [sigma]{sub [pi]°[gamma]} = [sigma]{sub [pi]°[rho]} x G{sub [gamma][rho]}2 with G{sub [gamma][rho]}2 = 1./160 ÷ 1./380 [1]. At E{sub CM} = 2.611 GeV, [sigma]{sub [pi]°[rho]} = (70 ± 30)[mu]b [2] which gives [sigma]{sub [pi]°{gamma}} = 184 ÷ 438 nb. To predict the cross section within a limited acceptance they assume that the angular production of [pi]°{gamma} is similar to the [pi]°[pi]° and [pi]°[rho] ones. To estimate the fraction of events with
