Measurement of the neutrino-oxygen neutral-current interaction cross section by observing nuclear de-excitation $\gamma$-rays

Abstract : We report the first measurement of the neutrino-oxygen neutral-current quasi-elastic (NCQE) cross section. It is obtained by observing nuclear de-excitation \gamma-rays which follow neutrino-oxygen interactions at the Super-Kamiokande water Cherenkov detector. We use T2K data corresponding to $3.01 \times 10^{20}$ protons on target. By selecting only events during the T2K beam window and with well-reconstructed vertices in the fiducial volume, the large background rate from natural radioactivity is dramatically reduced. We observe 43 events in the 4-30 MeV reconstructed energy window, compared with an expectation of 55.7, which includes an estimated 17.3 background events. The background is primarily non-quasielastic neutral-current interactions and has only 1.2 events from natural radioactivity. The flux-averaged NCQE cross section we measure is $1.35 \times 10^{-38}$ cm$^2$ with a 68% confidence interval of $(1.06, 1.94) \times 10^{-38}$ cm$^2$ at a median neutrino energy of 630 MeV, compared with the theoretical prediction of $2.01 \times 10^{-38}$ cm$^2$.
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Journal articles

http://hal.in2p3.fr/in2p3-00962301
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Submitted on : Friday, March 21, 2014 - 9:15:11 AM
Last modification on : Tuesday, January 25, 2022 - 12:48:10 PM

Citation

K. Abe, J. Adam, H. Aihara, T. Akiri, C. Andreopoulos, et al.. Measurement of the neutrino-oxygen neutral-current interaction cross section by observing nuclear de-excitation $\gamma$-rays. Physical Review D, American Physical Society, 2014, 90 (7), pp.072012. ⟨10.1103/PhysRevD.90.072012⟩. ⟨in2p3-00962301⟩

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