Publications [#248712] of Christopher Walter

Papers Published
1. Abe, K; Adam, J; Aihara, H; Akiri, T; Andreopoulos, C; Aoki, S; Ariga, A; Ariga, T; Assylbekov, S; Autiero, D; Barbi, M; Barker, GJ; Barr, G; Bass, M; Batkiewicz, M; Bay, F; Bentham, SW; Berardi, V; Berger, BE; Berkman, S; Bertram, I; Bhadra, S; Blaszczyk, FDM; Blondel, A; Bojechko, C; Bordoni, S; Boyd, SB; Brailsford, D; Bravar, A; Bronner, C; Buchanan, N; Calland, RG; Rodríguez, JC; Cartwright, SL; Castillo, R; Catanesi, MG; Cervera, A; Cherdack, D; Christodoulou, G; Clifton, A; Coleman, J et al., Observation of Electron Neutrino Appearance in a Muon Neutrino Beam, Phys. Rev. Lett., vol. 112 no. 6 (February, 2014), pp. 061802 [pdf], [doi] .

Abstract:
The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3$\sigma$ when compared to 4.92 $\pm$ 0.55 expected background events. In the PMNS mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles $\theta_12$, $\theta_23$, $\theta_13$, a mass difference $\Delta m^2_32$ and a CP violating phase $\delta_{\mathrmCP}$. In this neutrino oscillation scenario, assuming $|\Delta m^2_32| = 2.4 \times 10^{-3}$ $\rm eV^2$, $\sin^2 \theta_23 = 0.5$, and $\Delta m^2_32 >0$ ($\Delta m^2_32 <0$), a best-fit value of $\sin^2 2 \theta_13$ = $0.140^{+0.038}_{-0.032}$ ($0.170^{+0.045}_{-0.037}$) is obtained at $\delta_{\mathrmCP}=0$. When combining the result with the current best knowledge of oscillation parameters including the world average value of $\theta_13$ from reactor experiments, some values of $\delta_{\mathrmCP}$ are disfavored at the 90% CL.