A Search for Multi-Nucleon Production in the MINERvA Neutrino Experiment at Fermilab
Wielgus, Lauren A.
- The MINERvA experiment, or Main INjector Experiment for v-A, is equipped to closely study neutrino interactions on a range of targets and improve uncertainties in neutrino interaction cross sections. Quasi-elastic neutrino cross sections are mathematically modeled using form factors, which are calculated from experiment. The axial form factor depends upon the axial mass, measured by earlier bubble ... read morechamber experiments as 1.026 Â± 0.021 GeV. However, recent experiments have measured the axial mass as 1.14-1.35 GeV. This discrepancy may be due to poorly modeled nuclear effects, as bubble chamber experiments on deuterium are less affected by intra-nuclear interactions than recent experiments on larger nuclei. Current simulations use the impulse approximation method to model neutrino interactions, which treats each nucleon as an isolated particle and then applies corrections for their interactions. In this study, a search was carried out for meson exchange current (MEC) events in the MINERvA experiment, in which nucleons exchange a meson during an interaction with a neutrino. Multi-nucleon production is predicted to be a signal for MEC events and was used to find MEC candidates in this study, though multi-nucleon production does not exclusively result from such reactions. These events are ignored by the impulse approximation model, and have not been directly observed in a neutrino scattering experiment. By searching for these multi-nucleon production in both simulated and real data, the accuracy of current models can be measured. Isolating a sample of such events will show that neutrinos interact with multiple nucleons, rather than scattering off each single nucleons and point to deficiencies in the current modeling of intra-nuclear interactions.read less