Neutrino-induced one-pion production revisited: the ${\nu }_{\mu }n\to {\mu }^{-}n{\pi }^{+}$ channel

Abstract

Understanding single pion production reactions on free nucleons is the first step towards a correct description of these processes in nuclei, which are important for signal and background contributions in current and near future accelerator neutrino oscillation experiments. In this work, we reanalyze our previous studies of neutrino-induced one-pion production on nucleons for outgoing $\pi N$ invariant masses below 1.4 GeV. Our motivation is to get a better description of the ${\nu }_{\mu }n\to {\mu }^{-}n{\pi }^{+}$ cross section, for which current theoretical models give values significantly below data. This channel is very sensitive to the crossed $\Delta (1232)$ contribution and thus to spin 1/2 components in the Rarita-Schwinger $\Delta$ propagator. We show how these spin 1/2 components are nonpropagating and give rise to contact interactions. In this context, we point out that the discrepancy with experiment might be corrected by the addition of appropriate extra contact terms and argue that this procedure will provide a natural solution to the ${\nu }_{\mu }n\to {\mu }^{-}n{\pi }^{+}$ puzzle. To keep our model simple, in this work we propose to change the strength of the spin 1/2 components in the $\Delta$ propagator and use the ${\nu }_{\mu }n\to {\mu }^{-}n{\pi }^{+}$ data to constraint its value. With this modification, we now find a good reproduction of the ${\nu }_{\mu }n\to {\mu }^{-}n{\pi }^{+}$ cross section without affecting the good results previously obtained for the other channels. We also explore how this change in the $\Delta$ propagator affects our predictions for pion photoproduction and find also a better agreement with experiment than with the previous model.

21 pages, 1 Table, 8 Figures. Enlarged introduction and discussion. One new figure, One new panel in Figure 1

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Cited by in corpus (13)

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• A Precise Determination of (Anti)neutrino Fluxes with (Anti)neutrino-Hydrogen Interactions
• Exclusive final state hadron observables from neutrino-nucleus multi-nucleon knockout
• Neutral-current weak pion production off the nucleon in covariant chiral perturbation theory
• Hard exclusive neutrino production of a light meson
• Polarization Transfer in Weak Pion Production off the Nucleon
• Spin asymmetry in single pion production induced by weak interactions of neutrinos with polarized nucleons
• Summary of Workshop on Common Neutrino Event Generator Tools
• Model dependence of the polarization asymmetries in weak pion production off the nucleon
• Angular distributions in Monte Carlo event generation of weak single-pion production
• Weak pion-production and the second resonance region
• Weak Kaon Production off the nucleon and Watson's theorem
• Exclusive Hadron Observables in Neutrino Induced $2p2h$ Multinucleon Knockout