Search for neutral-current induced single photon production at the ND280 near detector in T2K

Date

2019

Authors

Abe, K.
Akutsu, R.
Ali, A.
Andreopoulos, C.
Anthony, L.
Antonova, M.
Aoki, S.
Ariga, A.
Ashida, Y.
Awataguchi, Y.

Journal Title

Journal ISSN

Volume Title

Publisher

Journal of Physics G: Nuclear and Particle Physics

Abstract

Neutrino neutral-current (NC) induced single photon production is a sub-leading order process for accelerator-based neutrino beam experiments including T2K. It is, however, an important process to understand because it is a background for electron (anti)neutrino appearance oscillation experiments. Here, we performed the first search of this process below 1 GeV using the fine-grained detector at the T2K ND280 off-axis near detector. By reconstructing single photon kinematics from electron–positron pairs, we achieved 95% pure gamma ray sample from $5.738\times {10}^{20}$ protons-on-targets neutrino mode data. We do not find positive evidence of NC induced single photon production in this sample. We set the model-dependent upper limit on the cross-section for this process, at $0.114\times {10}^{-38}$ cm2 (90% C.L.) per nucleon, using the J-PARC off-axis neutrino beam with an average energy of $\left\langle {E}_{\nu }\right\rangle \sim 0.6$ GeV. This is the first limit on this process below 1 GeV which is important for current and future oscillation experiments looking for electron neutrino appearance oscillation signals.

Description

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Citation

Abe, K., Akutsu, R., Ali, A., Andreopoulos, C., Anthony, L., Karlen, D., … Zykova, A. (2019). Search for neutral-current induced single photon production at the ND280 near detector in T2K. Journal of Physics G: Nuclear and Particle Physics, 46, 1-16. https://doi.org/10.1088/1361-6471/ab227d.