Implementation of the SuSAv2-meson exchange current 1p1h and 2p2h models in GENIE and analysis of nuclear effects in T2K measurements

Abstract

We first present the implementation and validation of the SuSAv2-MEC 1p1h and 2p2h models in the GENIE neutrino-nucleus interaction event generator and a comparison of the subsequent predictions to measurements of lepton and hadron kinematics from the T2K experiment. These predictions are also compared to those of other available models in GENIE. We additionally compare the semi-inclusive predictions of the implemented 1p1h model to those of the microscopic model on which SuSAv2 is based -Relativistic Mean Field (RMF) -to begin to test the validity of widelyused 'factorisation' assumptions employed by generators to predict hadron kinematics from inclusive input models. The results highlight that a more precise treatment of hadron kinematics in generators is essential in order to attain the few-% level uncertainty on neutrino interactions necessary for the next generation of accelerator-based long-baseline neutrino oscillation experiments.

Simultaneous measurement of the muon neutrino charged-current cross section on oxygen and carbon without pions in the final state at T2K

“…Other interaction modes are the GENIE default from model configuration "G18_10b" (but no tune is applied). FSI is considered through either the hA ("empirical") or hN ("cascade") final state interactions (FSI) models, as described in GENIE [68,69]; (vi) GENIE 3 SuSAv2: the GENIE implementation of the SuSAv2 model (1p1h þ 2p2h) [70][71][72][73][74], as described in [75]. Other interaction modes are as above and the FSI model is "hN"; (vii) RMF ð1p1hÞ þ SuSAv2 (2p2h): the relativistic mean field (RMF) model from Ref.…”

First combined measurement of the muon neutrino and antineutrino charged-current cross section without pions in the final state at T2K

“…[78], which uses the T2K measurements of final-state muon and proton kinematics and correlations in charged-current pionless interactions discussed in Ref. [17]; (vi) SUSAV2 is a complete implementation of the SuSAv2 model [79][80][81][82] in GENIE, as described in [83], where 1p1h is based on the Relativistic Mean Field approach [84] and 2p2h is based on the calculation from Ref. [85].…”

Data-based two-body current contribution to the neutrino-nucleus cross section

“…The most reliable ab initio computations exist only on a restricted phase space and for light nuclei. At larger neutrino energies theoretical model predictions differ significantly among themselves [22].…”