Publications [#248711] of Christopher Walter

Papers Published
  1. Renshaw, A; Abe, K; Hayato, Y; Iyogi, K; Kameda, J; Kishimoto, Y; Miura, M; Moriyama, S; Nakahata, M; Nakano, Y; Nakayama, S; Sekiya, H; Shiozawa, M; Suzuki, Y; Takeda, A; Takenaga, Y; Tomura, T; Ueno, K; Yokozawa, T; Wendell, RA; Irvine, T; Kajita, T; Kaneyuki, K; Lee, KP; Nishimura, Y; Okumura, K; McLachlan, T; Labarga, L; Berkman, S; Tanaka, HA; Tobayama, S; Kearns, E; Raaf, JL; Stone, JL; Sulak, LR; Goldhabar, M; Bays, K; Carminati, G; Kropp, WR; Mine, S; Smy, MB; Sobel, HW; Ganezer, KS et al., First Indication of Terrestrial Matter Effects on Solar Neutrino Oscillation, Phys. Rev. Lett., vol. 112 no. 9 (March, 2014), pp. 091805 [pdf], [doi] .

    We report an indication that the elastic scattering rate of solar $^8$B neutrinos with electrons in the Super-Kamiokande detector is larger when the neutrinos pass through the Earth during nighttime. We determine the day/night asymmetry, defined as the difference of the average day rate and average night rate divided by the average of those two rates, to be $(-3.2\pm1.1(\textstat)\pm0.5(\textsyst))\%$, which deviates from zero by 2.7 $\sigma$. Since the elastic scattering process is mostly sensitive to electron-flavored solar neutrinos, a non-zero day/night asymmetry implies that the flavor oscillations of solar neutrinos are affected by the presence of matter within the neutrinos' flight path. Super-Kamiokande's day/night asymmetry is consistent with neutrino oscillations for $4\times10^{-5}$eV$^2\leq\Delta m^2_21\leq7\times10^{-5}$eV$^2$ and large mixing values of $\theta_12$, at the $68\%$ C.L.