New multinucleon knockout model in NuWro Monte Carlo generator

TL;DR

This paper introduces a new multinucleon knockout model for the NuWro Monte Carlo generator, incorporating a novel sampling function and a 3p3h mechanism, calibrated against the Valencia model to improve neutrino interaction simulations.

Contribution

The paper presents a new multinucleon knockout model with a tunable nucleon sampling function and 3p3h contribution, enhancing NuWro's accuracy in simulating neutrino interactions.

Findings

The new model closely matches Valencia model predictions for outgoing nucleon momenta.

Inclusion of 3p3h mechanisms improves the description of multinucleon events.

Differences between models impact the interpretation of experimental hadronic data.

Abstract

We present the implementation and results of a new model for the n-particle n-hole ($\it{np-nh}$) contribution in the NuWro event generator, grounded in the theoretical framework established by the Valencia group in 2020. For the $\it{2p2h}$ component, we introduce a novel nucleon sampling function with tunable parameters to approximate correlations in the momenta of outgoing nucleons. These parameters are calibrated by comparing our results to those of the Valencia model across a range of incoming neutrino energies. In addition, our model incorporates a distinct contribution from the $\it{3p3h}$ mechanism. We discuss the differences between the new NuWro implementation, the original Valencia model, and the previous NuWro version, focusing on the distribution of outgoing nucleon momenta. Finally, we assess the impact of the hadronic model on experimental analyses involving hadronic observables.