Kajetan Niewczas

Modeling two-nucleon knock-out in neutrino-nucleus scattering

Accelerator-based neutrino oscillation experiments rely on the description of neutrino interactions with bound nucleons inside atomic nuclei. Neutrino fluxes used in modern experiments (T2K, NOvA, MiniBooNE) are peaked in the 1–5 GeV energy region where one can identify contributions from multiple interaction channels and various nuclear effects. The neutrino-nucleus cross sections in this region are known with a precision not exceeding 20% and have to be investigated further in pursuing to reduce systematic errors in oscillation measurements. The Ghent group focuses on providing a consistent description of this process in the intermediate energy region. Various interaction channels are modeled, including the two-nucleon knock-out (2p2h) that is known to provide one of the least controlled sources of uncertainty. The 2p2h final states are obtained via two mechanisms: short-range correlations [Phys.Rev.C 94 (2016) 024611] and meson-exchange currents [Phys.Rev.C 95 (2017) 054611]. Refined treatment of nuclear effects is achieved by constructing both bound-state and continuum nucleon wave functions through a Hartree-Fock calculation with an effective Skyrme-type interaction. I will present the results of the aforementioned references, as well as the current status and prospects of the project.