NEUTRINO NEUTRAL CURRENT EXCITATION OF 12C*(1+; T=1; 15.1 MeV)

Abstract

We report here the total cross-sections for [Formula: see text][Formula: see text], for incident neutrino energies from 16 MeV to 54 MeV, so as to provide theoretical values for comparison with the recent Karlsruhe-Rutherford Medium Energy Neutrino Experiment (KARMEN). The effects of the isospin mixing from the 1+; T=0; 12.7 MeV level of 12C are taken into account. The effect of the only strong interaction induced weak magnetism form factor is studied, as well as that of the isovector axial coupling. The nuclear models used are the combination of general 1p-shell wave functions of Cohen-Kurath for the 15.1 MeV level, and Gillet-VinhMau particle-hole wave functions with 2ħω excitations for 12.7 MeV level. The neutrino (antineutrino) flux averaged sum [Formula: see text] is found to be 9.86×10−42 cm2without isospin mixing and 9.83×10−42 cm2with isospin mixing (δ=0.05) to be compared with the KARMEN result for the sum as [10.8±1.1(stat)±1.2(syst)]×10−42 cm2.