Measurements of the decay KL→e+e-γ

The E799-II (KTeV) experiment at Fermilab has collected 83 262 K{sub L}{yields}e{sup +}e{sup -}{gamma}({gamma}) events above a background of 79 events. We measure a decay width, normalized to the K{sub L}{yields}{pi}{sup 0}{pi}{sup 0}{pi}{sub D}{sup 0} ({pi}{sup 0}{yields}{gamma}{gamma}, {pi}{sup 0}{yields}{gamma}{gamma}, {pi}{sub D}{sup 0}{yields}e{sup +}e{sup -}{gamma}({gamma})) decay width, of {gamma}(K{sub L}{yields}e{sup +}e{sup -}{gamma}({gamma}))/{gamma}(K{sub L}{yields}{pi}{sup 0}{pi}{sup 0}{pi}{sub D}{sup 0})=(1.3302{+-}0.0046{sub stat}{+-}0.0102{sub syst})x10{sup -3}. We also measure parameters of two K{sub L}{gamma}*{gamma} form factor models. In the Bergstroem-Masso-Singer parametrization, we find C{alpha}{sub K*}=-0.517{+-}0.030{sub stat}{+-}0.022{sub syst}. We separately fit for the first parameter of the D'Ambrosio-Isidori-Portoles model and find {alpha}{sub DIP}=-1.729{+-}0.043{sub stat}{+-}0.028{sub syst}.