CCQE, 2p2h excitations and \nu-energy reconstruction

Abstract

We analyze the MiniBooNE muon neutrino CCQE-like d\sigma/dT_\mu/dcos\theta_\mu data using a theoretical model that, among other nuclear effects, includes RPA correlations and 2p2h (multinucleon) mechanisms. These corrections turn out to be essential for the description of the data. We find that MiniBooNE CCQE-like data are fully compatible with former determinations of the nucleon axial mass M_A ~ 1.05 GeV. This is in sharp contrast with several previous analysis where anomalously large values of M_A ~ 1.4 GeV have been suggested. We also show that because of the the multinucleon mechanism effects, the algorithm used to reconstruct the neutrino energy is not adequate when dealing with quasielastic-like events. Finally, we analyze the MiniBooNE unfolded cross section, and show that it exhibits an excess (deficit) of low (high) energy neutrinos, which is an artifact of the unfolding process that ignores 2p2h mechanisms.