About estimations of a one-photon background in neutrino-oscillation experiments at low neutrino energies

The possible sources of one-photon radiation as a background for the quasi-elastic reaction {nu}{sub {mu}}+ n {sup {yields} {mu}-} + p are considered. They are relevant in experiments on determination of oscillation parameters at low neutrino energies (E{sub {nu} {approx}} 1 GeV). The estimation for the cross section of the reaction {nu}{sub {mu}}+ n {sup {yields} {mu}-} + p + {gamma} is given at E{sub {nu}}{sup lab} = 0.7 GeV as 0.65% of the corresponding cross section of quasielastic reaction. The mechanisms of quasi-elastic reaction are also considered at low neutrino energies on a quark level.