Flavor Ratio of Astrophysical Neutrinos above 35 TeV in IceCube.

  • Aartsen MG, Ackermann M, Adams J, Aguilar JA, Ahlers M, Ahrens M, Altmann D, Anderson T, Arguelles C, Arlen TC, Auffenberg J, Bai X, Barwick SW, Baum V, Bay R, Beatty JJ, Becker Tjus J, Becker KH, BenZvi S, Berghaus P, Berley D, Bernardini E, Bernhard A, Besson DZ, Binder G, Bindig D, Bissok M, Blaufuss E, Blumenthal J, Boersma DJ, Bohm C, Bos F, Bose D, Böser S, Botner O, Brayeur L, Bretz HP, Brown AM, Buzinsky N, Casey J, Casier M, Cheung E, Chirkin D, Christov A, Christy B, Clark K, Classen L, Clevermann F, Coenders S, Cowen DF, Cruz Silva AH, Daughhetee J, Davis JC, Day M, De André JP, De Clercq C, Dembinski H, De Ridder S, Desiati P, De Vries KD, De With M, DeYoung T, Díaz-Vélez JC, Dumm JP, Dunkman M, Eagan R, Eberhardt B, Ehrhardt T, Eichmann B, Eisch J, Euler S, Evenson PA, Fadiran O, Fazely AR, Fedynitch A, Feintzeig J, Felde J, Filimonov K, Finley C, Fischer-Wasels T, Flis S, Frantzen K, Fuchs T, Gaisser TK, Gaior R, Gallagher J, Gerhardt L, Gier D, Gladstone L, Glüsenkamp T, Goldschmidt A, Golup G, Gonzalez JG, Goodman JA, Góra D, Grant D, Gretskov P, Groh JC, Groß A, Ha C, Haack C, Haj Ismail A, Hallen P, Hallgren A, Halzen F, Hanson K, Hebecker D, Heereman D, Heinen D, Helbing K, Hellauer R, Hellwig D, Hickford S, Hill GC, Hoffman KD, Hoffmann R, Homeier A, Hoshina K, Huang F, Huelsnitz W, Hulth PO, Hultqvist K, Ishihara A, Jacobi E, Jacobsen J, Japaridze GS, Jero K, Jurkovic M, Kaminsky B, Kappes A, Karg T, Karle A, Kauer M, Keivani A, Kelley JL, Kheirandish A, Kiryluk J, Kläs J, Klein SR, Köhne JH, Kohnen G, Kolanoski H, Koob A, Köpke L, Kopper C, Kopper S, Koskinen DJ, Kowalski M, Kriesten A, Krings K, Kroll G, Kroll M, Kunnen J, Kurahashi N, Kuwabara T, Labare M, Lanfranchi JL, Larsen DT, Larson MJ, Lesiak-Bzdak M, Leuermann M, Lünemann J, Madsen J, Maggi G, Maruyama R, Mase K, Matis HS, Maunu R, McNally F, Meagher K, Medici M, Meli A, Meures T, Miarecki S, Middell E, Middlemas E, Milke N, Miller J, Mohrmann L, Montaruli T, Morse R, Nahnhauer R, Naumann U, Niederhausen H, Nowicki SC, Nygren DR, Obertacke A, Olivas A, Omairat A, O'Murchadha A, Palczewski T, Paul L, Penek Ö, Pepper JA, Pérez de los Heros C, Pfendner C, Pieloth D, Pinat E, Posselt J, Price PB, Przybylski GT, Pütz J, Quinnan M, Rädel L, Rameez M, Rawlins K, Redl P, Rees I, Reimann R, Relich M, Resconi E, Rhode W, Richman M, Riedel B, Robertson S, Rodrigues JP, Rongen M, Rott C, Ruhe T, Ruzybayev B, Ryckbosch D, Saba SM, Sander HG, Sandroos J, Santander M, Sarkar S, Schatto K, Scheriau F, Schmidt T, Schmitz M, Schoenen S, Schöneberg S, Schönwald A, Schukraft A, Schulte L, Schulz O, Seckel D, Sestayo Y, Seunarine S, Shanidze R, Smith MW, Soldin D, Spiczak GM, Spiering C, Stamatikos M, Stanev T, Stanisha NA, Stasik A, Stezelberger T, Stokstad RG, Stößl A, Strahler EA, Ström R, Strotjohann NL, Sullivan GW, Taavola H, Taboada I, Tamburro A, Ter-Antonyan S, Terliuk A, Tešić G, Tilav S, Toale PA, Tobin MN, Tosi D, Tselengidou M, Unger E, Usner M, Vallecorsa S, Van Eijndhoven N, Vandenbroucke J, Van Santen J, Vanheule S, Vehring M, Voge M, Vraeghe M, Walck C, Wallraff M, Weaver CH, Wellons M, Wendt C, Westerhoff S, Whelan BJ, Whitehorn N, Wichary C, Wiebe K, Wiebusch CH, Williams DR, Wissing H, Wolf M, Wood TR, Woschnagg K, Xu DL, Xu XW, Xu Y, Yanez JP, Yodh G, Yoshida S, Zarzhitsky P, Ziemann J, Zoll M. Flavor Ratio of Astrophysical Neutrinos above 35 TeV in IceCube. Physical review letters. 2015 May 1;114(114). 171102 p. PMID: 25978221 [PubMed]

Abstract

A diffuse flux of astrophysical neutrinos above 100 TeV has been observed at the IceCube Neutrino Observatory. Here we extend this analysis to probe the astrophysical flux down to 35 TeV and analyze its flavor composition by classifying events as showers or tracks. Taking advantage of lower atmospheric backgrounds for showerlike events, we obtain a shower-biased sample containing 129 showers and 8 tracks collected in three years from 2010 to 2013. We demonstrate consistency with the (fe:fμ:fτ)⊕≈(1:1:1)⊕ flavor ratio at Earth commonly expected from the averaged oscillations of neutrinos produced by pion decay in distant astrophysical sources. Limits are placed on nonstandard flavor compositions that cannot be produced by averaged neutrino oscillations but could arise in exotic physics scenarios. A maximally tracklike composition of (0:1:0)⊕ is excluded at 3.3σ, and a purely showerlike composition of (1:0:0)⊕ is excluded at 2.3σ.