Study of quasi-elastic reactions of ν and antineutrino in Gargamelle

The quasi-elastic cross-sections sigmasub(el)sup(tot) and dsigma/dq2 for the reactions (1) νn→μp and (2)antineutrinop→μsup(+)n have been measured by using the data of the ν Gargamelle collaboration. 687 ν events, candidates for reaction 1), and 476 antineutrino events, candidates for the reactions 2), have been used for the analysis. Because the ν and antineutrino interactions are on nuclei, suitable corrections for nuclear effects have been taken into account. In the framework of the ''usual'' V-A theory, by assuming for the axial form factor the dipolar form Fsub(A)(q2)=1.231/(1+q2/Msub(A)sup(2)), our data have been fitted to the differential cross-sections dsigma/dq2 integrated over the ν and antineutrino energy spectra and to the total cross-section sigmasub(el)sup(tot) as a function of the ν, antineutrino energy to determine the best value for the parameter Msub(A)