Search for proton decay via $p\to e^+\pi^0$ and $p\to \mu^+\pi^0$ with an enlarged fiducial volume in Super-Kamiokande I-IV

A. Takenaka , K. Abe , C. Bronner , Y. Hayato , M. Ikeda , S. Imaizumi , H. Ito , J. Kameda , Y. Kataoka , Y. Kato , Y. Kishimoto , Ll. Marti , M. Miura , S. Moriyama , T. Mochizuki , Y. Nagao , M. Nakahata , Y. Nakajima , S. Nakayama , T. Okada , A. Orii , G. Pronost , H. Sekiya , M. Shiozawa , Y. Sonoda , Y. Suzuki , A. Takeda , Y. Takemoto , T. Yano , R. Akutsu , S. Han , T. Kajita , K. Okumura , T. Tashiro , R. Wang , J. Xia , D. Bravo-Berguño , L. Labarga , P. Fernandez , B. Zaldivar , F.D.M. Blaszczyk , E. Kearns , J.L. Raaf , J.L. Stone , L. Wan , T. Wester , B.W. Pointon , J. Bian , N.J. Griskevich , W.R. Kropp , S. Locke , S. Mine , M.B. Smy , H.W. Sobel , V. Takhistov , P. Weatherly , K.S. Ganezer , J. Hill , J.Y. Kim , I.T. Lim , R.G. Park , B. Bodur , K. Scholberg , C.W. Walter , A. Coffani (1) , O. Drapier (1) , S. El Hedri (1) , A. Giampaolo (1) , M. Gonin (1) , Th.A. Mueller (1) , P. Paganini (1) , B. Quilain (1) , T. Ishizuka , T. Nakamura , J.S. Jang , J.G. Learned , S. Matsuno , L.H.V. Anthony , R.P. Litchfield , A.A. Sztuc , Y. Uchida , V. Berardi , M.G. Catanesi , E. Radicioni , N.F. Calabria , L.N. Machado , G. de Rosa , G. Collazuol , F. Iacob , M. Lamoureux , N. Ospina , L. Ludovici , Y. Nishimura , S. Cao , M. Friend , T. Hasegawa , T. Ishida , M. Jakkapu , T. Kobayashi , T. Matsubara , T. Nakadaira , Y. Oyama , K. Sakashita , T. Sekiguchi , T. Tsukamoto , M. Hasegawa , Y. Isobe , H. Miyabe , Y. Nakano , T. Shiozawa , T. Sugimoto , A.T. Suzuki , Y. Takeuchi , S. Yamamoto , A. Ali , Y. Ashida , J. Feng , S. Hirota , A.K. Ichikawa , M. Jiang , T. Kikawa , M. Mori , Ke. Nakamura , T. Nakaya , R.A. Wendell , K. Yasutome , N. Mccauley , P. Mehta , A. Pritchard , K.M. Tsui , Y. Fukuda , Y. Itow , H. Menjo , T. Niwa , K. Sato , M. Taani , M. Tsukada , P. Mijakowski , K. Frankiewicz , C.K. Jung , G. Santucci , C. Vilela , M.J. Wilking , C. Yanagisawa , D. Fukuda , M. Harada , K. Hagiwara , T. Horai , H. Ishino , S. Ito , Y. Koshio , W. Ma , N. Piplani , S. Sakai , M. Sakuda , Y. Takahira , C. Xu , Y. Kuno , G. Barr , D. Barrow , L. Cook , C. Simpson , D. Wark , F. Nova , T. Boschi , F. Di Lodovico , S. Molina Sedgwick , S. Zsoldos , J.Y. Yang , S.J. Jenkins , J.M. Mcelwee , M.D. Thiesse , L.F. Thompson , H. Okazawa , Y. Choi , S.B. Kim , I. Yu , K. Nishijima , M. Koshiba , K. Iwamoto , N. Ogawa , M. Yokoyama , A. Goldsack , K. Martens , M.R. Vagins , M. Kuze , M. Tanaka , T. Yoshida , M. Inomoto , M. Ishitsuka , R. Matsumoto , K. Ohta , M. Shinoki , J.F. Martin , C.M. Nantais , H.A. Tanaka , T. Towstego , M. Hartz , A. Konaka , P. de Perio , N.W. Prouse , S. Chen , B.D. Xu , M. Posiadala-Zezula , B. Richards , B. Jamieson , J. Walker , A. Minamino , K. Okamoto , G. Pintaudi , R. Sasaki

1 LLR - Laboratoire Leprince-Ringuet

We have searched for proton decay via $p\to e^+\pi^0$ and $p\to \mu^+\pi^0$ modes with the enlarged fiducial volume data of Super-Kamiokande from April 1996 to May 2018, which corresponds to 450 kton$\cdot$years exposure. We have accumulated about 25% more livetime and enlarged the fiducial volume of the Super-Kamiokande detector from 22.5 kton to 27.2 kton for this analysis, so that 144 kton$\cdot$years of data, including 78 kton$\cdot$years of additional fiducial volume data, has been newly analyzed. No candidates have been found for $p\to e^+\pi^0$ and one candidate remains for $p\to \mu^+\pi^0$ in the conventional 22.5 kton fiducial volume and it is consistent with the atmospheric neutrino background prediction. We set lower limits on the partial lifetime for each of these modes: $\tau/B(p\to e^+\pi^0) > 2.4 \times 10^{34}$ years and $\tau/B(p\to \mu^+\pi^0) > 1.6 \times 10^{34}$ years at 90% confidence level.

Mots clés: Particle Physics Experiments; p: decay; neutrino: atmosphere; neutrino: background; KAMIOKANDE; lifetime; p: branching ratio; lower limit; experimental results; p --> positron pi0; p --> muon+ pi0; S016.6; S016.7

Domaines: Physique des Hautes Energies - Expérience [hep-ex]

A. Takenaka, K. Abe, C. Bronner, Y. Hayato, M. Ikeda, et al.. Search for proton decay via $p\to e^+\pi^0$ and $p\to \mu^+\pi^0$ with an enlarged fiducial volume in Super-Kamiokande I-IV. Phys.Rev.D, 2020, 102 (11), pp.112011. ⟨10.1103/PhysRevD.102.112011⟩. ⟨hal-03022678⟩