Four Momentum Transfer Discrepancy in the Charged Current π+ Production in the MiniBooNE: Data vs. Theory

The MiniBooNE experiment has collected what is currently the world's largest sample of νμ charged current single charged pion (CClπ+) interactions, roughly 46,000 events. The purity of the CClπ+ sample is 87% making this the purest event sample observed in the MiniBooNE detector. The average energy of neutrinos producing CCπ+ interactions in MiniBooNE is about 1 GeV, therefore the study of these events can provide insight into both resonant and coherent pion production processes. In this talk, we will discuss the long-standing discrepancy in four-momentum transfer observed between CCπ+ data and existing predictions. Several attempts to address this problem will be presented. Specifically, the Rein-Sehgal model has been extended to include muon mass terms for both resonant and coherent production. Using calculations from, an updated form for the vector form factor has also been adopted. The results of this improved description of CCπ+ production will be compared to the high statistics MiniBooNE CCπ+ data and several existing parametrizations of the axial vector form factor