# Neutron-antineutron oscillation search using a 0.37 megaton-years exposure of Super-Kamiokande

Abe, K, Bronner, C, Hayato, Y, Ikeda, M, Imaizumi, S, Ito, H, Kameda, J, Kataoka, Y, Miura, M, Moriyama, S
et al (show 189 more authors) (2021) Neutron-antineutron oscillation search using a 0.37 megaton-years exposure of Super-Kamiokande. PHYSICAL REVIEW D, 103 (1). 012008-.

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## Abstract

As a baryon number violating process with $\Delta B=2$, neutron-antineutron oscillation ($n\to\bar n$) provides a unique test of baryon number conservation. We have performed a search for $n\to\bar n$ oscillation with bound neutrons in Super-Kamiokande, with the full data set from its first four run periods, representing an exposure of 0.37~Mton-years. The search used a multivariate analysis trained on simulated $n\to\bar n$ events and atmospheric neutrino backgrounds and resulted in 11 candidate events with an expected background of 9.3 events. In the absence of statistically significant excess, we derived a lower limit on $\bar n$ appearance lifetime in $^{16}$O nuclei of $3.6\times{10}^{32}$ years and on the neutron-antineutron oscillation time of $\tau_{n\to\bar n} > 4.7\times10^{8}$~s at 90\% C.L..

Item Type: Article hep-ex, hep-ex Symplectic Admin 02 Mar 2021 08:06 18 Jan 2023 22:58 10.1103/PhysRevD.103.012008 https://journals.aps.org/prd/abstract/10.1103/Phys... https://livrepository.liverpool.ac.uk/id/eprint/3116332