2209.08609 — arXiv2

Neutron Tagging following Atmospheric Neutrino Events in a Water Cherenkov Detector

hep-ex

/ Published

Sep 18, 2022

/ Updated

Sep 20, 2022

/ Categories

hep-ex astro-ph.IM physics.ins-det

/ Links

/ Authors

K. Abe, Y. Haga, Y. Hayato, K. Hiraide, K. Ieki, M. Ikeda, S. Imaizumi, K. Iyogi, J. Kameda, Y. Kanemura

and 296 more authors

Y. Kataoka, Y. Kato, Y. Kishimoto, S. Miki, S. Mine, M. Miura, T. Mochizuki, S. Moriyama, Y. Nagao, M. Nakahata, T. Nakajima, Y. Nakano, S. Nakayama

, D. Bravo-Berguño

, F. d. M. Blaszczyk

, B. W. Pointon

, N. J. Griskevich

, K. S. Ganezer

, B. L. Hartfiel

, E. O'Sullivan

, Th. A. Mueller

, J. G. Learned

, L. H. V. Anthony

, R. P. Litchfield

, M. G. Catanesi

, R. A. Intonti

, N. F. Calabria

, L. N. Machado

, F. Di Lodovico

, S. Molina Sedgwick

, R. A. Wendell

, T. Suzuki M. Tsukada

, K. Frankiewicz

, P. Mijakowski

, J. L. Palomino

, M. J. Wilking

, C. Yanagisawa

, S. J. Jenkins

, J. M. McElwee

, M. D. Thiesse

, L. F. Thompson

, A. K. Ichikawa

, R. G. Calland

, C. M. Nantais

, M. Posiadala-Zezula

/ Abstract

We present the development of neutron-tagging techniques in Super-Kamiokande IV using a neural network analysis. The detection efficiency of neutron capture on hydrogen is estimated to be 26%, with a mis-tag rate of 0.016 per neutrino event. The uncertainty of the tagging efficiency is estimated to be 9.0%. Measurement of the tagging efficiency with data from an Americium-Beryllium calibration agrees with this value within 10%. The tagging procedure was performed on 3,244.4 days of SK-IV atmospheric neutrino data, identifying 18,091 neutrons in 26,473 neutrino events. The fitted neutron capture lifetime was measured as 218 \pm 9 μs.