Quantifying Effects Of Final State Interactions On Pion Production In DUNE Using Monte Carlo Event Generators

The analysis of pion production in neutrino-nucleus scattering is crucial to quantify the effect of final state interactions (FSI) in the energy regime of DUNE and other long-baseline neutrino experiments since FSI modify the number of pions that emerge in the final state as compared to the number of pions produced in the initial (primary) state. Not only the number of pions but also their charge gets changed due to the prevailing FSI effects. In the present work, we will study the effect of FSI on pions after their production at the initial neutrino-nucleus interaction vertex using two different Monte Carlo (MC) simulation tools viz. GENIE (version: 3.0.6) and NuWro (version: 19.2.2). Considering the DUNE experimental set-up, we observe pion production in ν_µ and ⁴⁰Ar nucleus interactions for an event sample of 1 million for each generator. We find that there are some differences in the pion number observed in the primary and final states of two generators and that the differences are above statistical fluctuations. We observe that GENIE (version: 3.0.6) is more responsive (less transparent) to absorption and charge exchange processes as compared to NuWro (version: 19.2.2).