A search for dinucleon decay into pions with the Super-Kamiokande detector has been performed with an exposure of 282.1 kiloton-years. Dinucleon decay is a process that violates baryon number by two units. We present the first search for dinucleon decay to pions in a large water-Cherenkov detector. The modes O16(pp)→C14π+π+, O16(pn)→N14π+π0, and O16(nn)→O14π0π0 are investigated. No significant excess in the Super-Kamiokande data has been found, so a lower limit on the lifetime of the process per oxygen nucleus is determined. These limits are τpp→π+π+>7.22×1031years, τpn→π+π0>1.70×1032years, and τnn→π0π0>4.04×1032years. The lower limits on each mode are about 2 orders of magnitude better than previous limits from searches for dinucleon decay in iron.
|ジャーナル||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|出版ステータス||Published - 2015 4 28|
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