Indication of electron neutrino appearance from an accelerator-produced off-axis muon neutrino beam.


The T2K experiment observes indications of ν(μ) → ν(e) appearance in data accumulated with 1.43×10(20) protons on target. Six events pass all selection criteria at the far detector. In a three-flavor neutrino oscillation scenario with |Δm(23)(2)| = 2.4×10(-3)  eV(2), sin(2)2θ(23) = 1 and sin(2)2θ(13) = 0, the expected number of such events is 1.5±0.3(syst). Under this hypothesis, the probability to observe six or more candidate events is 7×10(-3), equivalent to 2.5σ significance. At 90% C.L., the data are consistent with 0.03(0.04) < sin(2)2θ(13) < 0.28(0.34) for δ(CP) = 0 and a normal (inverted) hierarchy.

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@article{Abe2011IndicationOE, title={Indication of electron neutrino appearance from an accelerator-produced off-axis muon neutrino beam.}, author={K Abe and N Abgrall and Y Ajima and H Aihara and J B Albert and C Andreopoulos and B Andrieu and S Aoki and O Araoka and J Argyriades and A Ariga and T Ariga and S Assylbekov and D Autiero and A Badertscher and M Barbi and G J Barker and G Barr and M Bass and F Bay and S Bentham and V Berardi and B E Berger and I Bertram and M Besnier and J Beucher and D Beznosko and S Bhadra and F d M M Blaszczyk and A Blondel and C Bojechko and J Bouchez and S B Boyd and A Bravar and C Bronner and D G Brook-Roberge and N Buchanan and H Budd and D Calvet and S L Cartwright and A Carver and R Castillo and M G Catanesi and A Cazes and A Cervera and C Chavez and S Choi and G Christodoulou and J Coleman and W Coleman and G Collazuol and K Connolly and A Curioni and A Dabrowska and I Danko and R Das and G S Davies and S Davis and M Day and G De Rosa and J P A M de Andr{\'e} and P de Perio and A Delbart and C Densham and F Di Lodovico and S Di Luise and P Dinh Tran and J Dobson and U Dore and O Drapier and F Dufour and J Dumarchez and S Dytman and M Dziewiecki and M Dziomba and S Emery and A Ereditato and L Escudero and L S Esposito and M Fechner and A Ferrero and A J Finch and E Frank and Y Fujii and Y Fukuda and V Galymov and F C Gannaway and A Gaudin and A Gendotti and M A George and S Giffin and C Giganti and K Gilje and T Golan and M Goldhaber and J J Gomez-Cadenas and M Gonin and N Grant and A Grant and P Gumplinger and P Guzowski and A Haesler and M D Haigh and K Hamano and C Hansen and D Hansen and T Hara and P F Harrison and B Hartfiel and M Hartz and T Haruyama and T Hasegawa and N C Hastings and S Hastings and A Hatzikoutelis and K Hayashi and Y Hayato and C Hearty and R L Helmer and R Henderson and N Higashi and J Hignight and E Hirose and J Holeczek and S Horikawa and A Hyndman and A K Ichikawa and K Ieki and M Ieva and M Iida and M Ikeda and J Ilic and J Imber and T Ishida and C Ishihara and T Ishii and S J Ives and M Iwasaki and K Iyogi and A Izmaylov and B Jamieson and R A Johnson and K K Joo and G V Jover-Manas and C K Jung and H Kaji and T Kajita and H Kakuno and J Kameda and K Kaneyuki and D Karlen and K Kasami and I Kato and E Kearns and M Khabibullin and F Khanam and A Khotjantsev and D Kielczewska and T Kikawa and J Kim and J Y Kim and S B Kim and N Kimura and B Kirby and J Kisiel and P Kitching and T Kobayashi and G Kogan and S Koike and A Konaka and L L Kormos and A Korzenev and K Koseki and Y Koshio and Y Kouzuma and K Kowalik and V Kravtsov and I Kreslo and W Kropp and H Kubo and Y Kudenko and N Kulkarni and R Kurjata and T Kutter and J Lagoda and K Laihem and M Laveder and K P Lee and P T Le and J M Levy and C Licciardi and I T Lim and T Lindner and R P Litchfield and M Litos and A Longhin and G D Lopez and P F Loverre and L Ludovici and T Lux and M Macaire and K Mahn and Y Makida and M Malek and S Manly and A Marchionni and A D Marino and J Marteau and J F Martin and T Maruyama and T Maryon and J Marzec and P Masliah and E L Mathie and C Matsumura and K Matsuoka and V Matveev and K Mavrokoridis and E Mazzucato and N McCauley and K S McFarland and C McGrew and T McLachlan and M Messina and W Metcalf and C Metelko and M Mezzetto and P Mijakowski and C A Miller and A Minamino and O Mineev and S Mine and A D Missert and G Mituka and M Miura and K Mizouchi and L Monfregola and F Moreau and B Morgan and S Moriyama and A Muir and A Murakami and M Murdoch and S Murphy and J Myslik and T Nakadaira and M Nakahata and T Nakai and K Nakajima and T Nakamoto and K Nakamura and S Nakayama and T Nakaya and D Naples and M L Navin and B Nelson and T C Nicholls and K Nishikawa and H Nishino and J A Nowak and M Noy and Y Obayashi and T Ogitsu and H Ohhata and T Okamura and K Okumura and T Okusawa and S M Oser and M Otani and R A Owen and Y Oyama and T Ozaki and M Y Pac and V Palladino and V Paolone and P Paul and D Payne and G F Pearce and J D Perkin and V Pettinacci and F Pierre and E Poplawska and B Popov and M Posiadala and J-M Poutissou and R Poutissou and P Przewlocki and W Qian and J L Raaf and E Radicioni and P N Ratoff and T M Raufer and M Ravonel and M Raymond and F Retiere and A Robert and P A Rodrigues and E Rondio and J M Roney and B Rossi and S Roth and A Rubbia and D Ruterbories and S Sabouri and R Sacco and K Sakashita and F S{\'a}nchez and A Sarrat and K Sasaki and K Scholberg and J Schwehr and M Scott and D I Scully and Y Seiya and T Sekiguchi and H Sekiya and M Shibata and Y Shimizu and M Shiozawa and S Short and M Siyad and R J Smith and M Smy and J T Sobczyk and H Sobel and M Sorel and A Stahl and P Stamoulis and J Steinmann and B Still and J Stone and C Strabel and L R Sulak and R Sulej and P Sutcliffe and A Suzuki and K Suzuki and S Suzuki and S Y Suzuki and Y Suzuki and T Szeglowski and M Szeptycka and R Tacik and M Tada and S Takahashi and A Takeda and Y Takenaga and Y Takeuchi and K Tanaka and H A Tanaka and M Tanaka and M M Tanaka and N Tanimoto and K Tashiro and I Taylor and A Terashima and D Terhorst and R Terri and L F Thompson and A Thorley and W Toki and T Tomaru and Y Totsuka and C Touramanis and T Tsukamoto and M Tzanov and Y Uchida and K Ueno and A Vacheret and M Vagins and G Vasseur and T Wachala and J J Walding and A V Waldron and C W Walter and P J Wanderer and J Wang and M A Ward and G P Ward and D Wark and M O Wascko and A Weber and R Wendell and N West and L H Whitehead and G Wikstr{\"{o}m and R J Wilkes and M J Wilking and J R Wilson and R J Wilson and T Wongjirad and S Yamada and Y Yamada and A Yamamoto and K Yamamoto and Y Yamanoi and H Yamaoka and C Yanagisawa and T Yano and S Yen and N Yershov and M Yokoyama and A Zalewska and J Zalipska and L Zambelli and K Zaremba and M Ziembicki and E D Zimmerman and M Zito and J Żmuda}, journal={Physical review letters}, year={2011}, volume={107 4}, pages={041801} }