Relevance of two-boson exchange effect in quasi-elastic charged current neutrino–nucleon interaction

Two-boson exchange (TBE) correction in νn→l−pνn→l−p and ν¯p→l+n reactions is estimated. The TBE contribution is given by Wγ   box diagrams. The calculations are performed for 1 GeV neutrinos and for the MiniBooNE and the T2K energy spectra. The TBE correction to the total cross section is of the order of 2–4%2–4% (with respect to the Born contribution) in the case of νeνe and ν¯e and 1–2%1–2% in the case of νμνμ and ν¯μ.