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arXiv:1606.07538hep-ex

Solar Neutrino Measurements in Super-Kamiokande-IV

Super-Kamiokande Collaboration, :, K. Abe, Y. Haga, Y. Hayato, M. Ikeda, K. Iyogi, J. Kameda, Y. Kishimoto, Ll. Marti, M. Miura, S. Moriyama, M. Nakahata, T. Nakajima, S. Nakayama, A. Orii, H. Sekiya, M. Shiozawa, Y. Sonoda, A. Takeda, H. Tanaka, Y. Takenaga, S. Tasaka, T. Tomura, K. Ueno, T. Yokozawa, R. Akutsu, T. Irvine, H. Kaji, T. Kajita, I. Kametani, K. Kaneyuki, K. P. Lee, Y. Nishimura, T. McLachlan, K. Okumura, E. Richard, L. Labarga, P. Fernandez, F. d. M. Blaszczyk, J. Gustafson, C. Kachulis, E. Kearns, 32 J. L. Raaf, J. L. Stone, 32 L. R. Sulak, S. Berkman, S. Tobayama, M. Goldhaber, K. Bays, G. Carminati, N. J. Griskevich, W. R. Kropp, S. Mine, A. Renshaw, M. B. Smy, H. W. Sobel, V. Takhistov, P. Weatherly, K. S. Ganezer, B. L. Hartfiel, J. Hill, W. E. Keig, N. Hong, J. Y. Kim, I. T. Lim, R. G. Park, T. Akiri, J. B. Albert, A. Himmel, Z. Li, E. O'Sullivan, K. Scholberg, C. W. Walter, T. Wongjirad, T. Ishizuka, T. Nakamura, J. S. Jang, K. Choi, J. G. Learned, S. Matsuno, S. N. Smith, M. Friend, T. Hasegawa, T. Ishida, T. Ishii, T. Kobayashi, T. Nakadaira, K. Nakamura, K. Nishikawa, Y. Oyama, K. Sakashita, T. Sekiguchi, T. Tsukamoto, Y. Nakano, A. T. Suzuki, Y. Takeuchi, T. Yano, S. V. Cao, T. Hayashino, T. Hiraki, S. Hirota, K. Huang, K. Ieki, M. Jiang, T. Kikawa, A. Minamino, A. Murakami, T. Nakaya, N. D. Patel, K. Suzuki, S. Takahashi, R. A. Wendell, Y. Fukuda, Y. Itow, G. Mitsuka, F. Muto, T. Suzuki, P. Mijakowski, K. Frankiewicz, J. Hignight, J. Imber, C. K. Jung, X. Li, J. L. Palomino, G. Santucci, I. Taylor, C. Vilela, M. J. Wilking, C. Yanagisawa, D. Fukuda, H. Ishino, T. Kayano, A. Kibayashi, Y. Koshio, T. Mori, M. Sakuda, J. Takeuchi, R. Yamaguchi, Y. Kuno, R. Tacik, S. B. Kim, H. Okazawa, Y. Choi, K. Ito, K. Nishijima, M. Koshiba, Y. Totsuka, Y. Suda, M. Yokoyama, C. Bronner, R. G. Calland, M. Hartz, K. Martens, Y. Obayashi, Y. Suzuki, M. R. Vagins, C. M. Nantais, J. F. Martin, P. de Perio, H. A. Tanaka, A. Konaka, S. Chen, H. Sui, L. Wan, Z. Yang, H. Zhang, Y. Zhang, K. Connolly, M. Dziomba, R. J. Wilkes

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Abstract

Upgraded electronics, improved water system dynamics, better calibration and analysis techniques allowed Super-Kamiokande-IV to clearly observe very low-energy 8B solar neutrino interactions, with recoil electron kinetic energies as low as 3.49 MeV. Super-Kamiokande-IV data-taking began in September of 2008; this paper includes data until February 2014, a total livetime of 1664 days. The measured solar neutrino flux is (2.308+-0.020(stat.) + 0.039-0.040(syst.)) x 106/(cm2sec) assuming no oscillations. The observed recoil electron energy spectrum is consistent with no distortions due to neutrino oscillations. An extended maximum likelihood fit to the amplitude of the expected solar zenith angle variation of the neutrino-electron elastic scattering rate in SK-IV results in a day/night asymmetry of (-3.6+-1.6(stat.)+-0.6(syst.))%. The SK-IV solar neutrino data determine the solar mixing angle as sin2 theta_12 = 0.327+0.026-0.031, all SK solar data (SK-I, SK-II, SK III and SKIV) measures this angle to be sin2 theta_12 = 0.334+0.027-0.023, the determined mass-squared splitting is Delta m2_21 = 4.8+1.5-0.8 x10-5 eV2.

arXiv comments
Submitted to Physical Review D; 23 pages, 40 figures
Journal reference
DOI
doi:10.1103/PhysRevD.94.052010
Subjects
hep-exHigh Energy Physics, Experiment physics.ins-detInstrumentation and Detectors

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  1. The Sun seen through the Earth in “neutrino light” (2007) 3 comments

    • This article is quite old but a more recent measurement from the same experiment (Super-K) used a 1600 day dataset. Of that 1600 days of exposure 860 "days" were nights. So it's pretty close to half and half. (Cite: Section V-B, bottom left of page 22, of…

      0PingWithJesusView on HNParent context

    • The detector does not "look" in any direction, it is in no way "pointed" at the sun. It records the direction of all events that occur within its volume. But once recorded they compare the direction of all events with the direction from the sun at the time of the event. The…

      0PingWithJesusView on HNParent context

    • For their more recent data they reported seeing ~32000 solar neutrino events over a 1600 day dataset (cite: top-right of page 13 https://arxiv.org/pdf/1606.07538.pdf). Their detector nowadays is more sensitive than it was when the OP was published so I would estimate the image…

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