Measurements of the branching fraction and decay distributions for K{sub L}{yields}{pi}{sup {+-}}{mu}{sup {+-}}{nu}{gamma} and K{sub L}{yields}{pi}{sup {+-}}e{sup {+-}}{nu}{gamma}

We present measurements of R{sub Kl3{gamma}}{identical_to}{gamma}(K{sub L}{yields}{pi}{sup {+-}}l{sup {+-}}{nu}{gamma};E{sub {gamma}}*>10 MeV)/{gamma}(K{sub L}{yields}{pi}{sup {+-}}l{sup {+-}}{nu}), where l={mu} or e, and E{sub {gamma}}* is the photon energy in the kaon rest frame. These measurements are based on K{sub L} decays collected in 1997 by the KTeV (E832) experiment at Fermilab. With samples of 1385 K{sub L}{yields}{pi}{sup {+-}}{mu}{sup {+-}}{nu}{gamma} and 14221 K{sub L}{yields}{pi}{sup {+-}}e{sup {+-}}{nu}{gamma} candidates, we find R{sub K{mu}}{sub 3{gamma}}=(0.530{+-}0.019)% and R{sub Ke3{gamma}}=(4.942{+-}0.062)%. We also examine distributions of photon energy and lepton-photon angle.