Author:
,Agafonova N.,Aleksandrov A.,Anokhina A.,Aoki S.,Ariga A.,Ariga T.,Bertolin A.,Bozza C.,Brugnera R.,Buonaura A.,Buontempo S.,Chernyavskiy M.,Chukanov A.,Consiglio L.,D’Ambrosio N.,De Lellis G.,De Serio M.,del Amo Sanchez P.,Di Crescenzo A.,Di Ferdinando D.,Di Marco N.,Dmitrievsky S.,Dracos M.,Duchesneau D.,Dusini S.,Dzhatdoev T.,Ebert J.,Ereditato A.,Favier J.,Fini R. A.,Fornari F.,Fukuda T.,Galati G.,Garfagnini A.,Gentile V.,Goldberg J.,Gornushkin Y.,Gorbunov S.,Grella G.,Guler A. M.,Gustavino C.,Hagner C.,Hara T.,Hayakawa T.,Hollnagel A.,Hosseini B.,Ishiguro K.,Iuliano A.,Jakovcic K.,Jollet C.,Kamiscioglu C.,Kamiscioglu M.,Kim S. H.,Kitagawa N.,Klicek B.,Kodama K.,Komatsu M.,Kose U.,Kreslo I.,Laudisio F.,Lauria A.,Ljubicic A.,Longhin A.,Loverre P.,Malgin A.,Malenica M.,Mandrioli G.,Matsuo T.,Matveev V.,Mauri N.,Medinaceli E.,Meisel F.,Meregaglia A.,Mikado S.,Miyanishi M.,Mizutani F.,Monacelli P.,Montesi M. C.,Morishima K.,Muciaccia M. T.,Naganawa N.,Naka T.,Nakamura M.,Nakano T.,Niwa K.,Okateva N.,Ogawa S.,Ozaki K.,Paoloni A.,Paparella L.,Park B. D.,Pasqualini L.,Pastore A.,Patrizii L.,Pessard H.,Podgrudkov D.,Polukhina N.,Pozzato M.,Pupilli F.,Roda M.,Roganova T.,Rokujo H.,Rosa G.,Ryazhskaya O.,Sato O.,Schembri A.,Shakiryanova I.,Shchedrina T.,Shibuya H.,Shibayama E.,Shiraishi T.,Simone S.,Sirignano C.,Sirri G.,Sotnikov A.,Spinetti M.,Stanco L.,Starkov N.,Stellacci S. M.,Stipcevic M.,Strolin P.,Takahashi S.,Tenti M.,Terranova F.,Tioukov V.,Vasina S.,Vilain P.,Voevodina E.,Votano L.,Vuilleumier J. L.,Wilquet G.,Yoon C. S.
Abstract
Abstract
The OPERA experiment has discovered the tau neutrino appearance in the CNGS muon neutrino beam, in agreement with the 3 neutrino flavour oscillation hypothesis. The OPERA neutrino interaction target, made of Emulsion Cloud Chambers, was particularly efficient in the reconstruction of electromagnetic showers. Moreover, thanks to the very high granularity of the emulsion films, showers induced by electrons can be distinguished from those induced by π
0s, thus allowing the detection of charged current interactions of electron neutrinos. In this paper the results of the search for electron neutrino events using the full dataset are reported. An improved method for the electron neutrino energy estimation is exploited. Data are compatible with the 3 neutrino flavour mixing model expectations and are used to set limits on the oscillation parameters of the 3+1 neutrino mixing model, in which an additional mass eigenstate m
4 is introduced. At high Δm
41
2
(≳0.1 eV2), an upper limit on sin2 2θ
μe
is set to 0.021 at 90% C.L. and Δm
41
2
≳ 4 × 10− 3 eV2 is excluded for maximal mixing in appearance mode.
Reference38 articles.
1. OPERA collaboration, M. Guler at al., An appearance experiment to search for νμ ↔ ν
τ oscillations in the CNGS beam. Experimental proposal, SPSC-2000-028 (2000) [CERN-SPSC-P-318] [LNGS-P25-00].
2. R. Acquafredda et al., The OPERA experiment in the CERN to Gran Sasso neutrino beam, 2009 JINST 4 P04018 [INSPIRE].
3. G. Acquistapace et al., The CERN neutrino beam to Gran Sasso (NGS), CERN-98-02 (1998) [INFN/AE-98/05].
4. R. Bailey et al., The CERN neutrino beam to Gran Sasso (NGS). Addendum to report CERN-98-02, INFN/AE-98/05, CERN-SL/99-034(DI) (1999) [INFN/AE-99/05].
5. OPERA collaboration, N. Agafonova et al., Discovery of τ neutrino appearance in the CNGS neutrino beam with the OPERA experiment, Phys. Rev. Lett. 115 (2015) 121802 [arXiv:1507.01417] [INSPIRE].