All-flavor Search for a Diffuse Flux of Cosmic Neutrinos with Nine Years of ANTARES Data

127The ANTARES detector is at present the most sensitive neutrino telescope in the northern hemisphere. The highly significant cosmic neutrino excess observed by the Antarctic IceCube detector can be studied with ANTARES, exploiting its complementing field of view, exposure, and lower energy threshold. Searches for an all-flavor diffuse neutrino signal, covering nine years of ANTARES data taking, are presented in this Letter. Upward-going events are used to reduce the atmospheric muon background. This work includes for the first time in ANTARES both track-like (mainly nu mu) and shower-like (mainly nu(e)) events in this kind of analysis. Track-like events allow for an increase of the effective volume of the detector thanks to the long path traveled by muons in rock and/ or sea water. Shower-like events are well reconstructed only when the neutrino interaction vertex is close to, or inside, the instrumented volume. A mild excess of high-energy events over the expected background is observed in nine years of ANTARES data in both samples. The best fit for a single power-law cosmic neutrino spectrum, in terms of perflavor flux at 100 TeV, is Phi(1f)(0) (100 TeV) = (1.7 +/- 1.0) x 10(-18) GeV-1 cm(-2) s(-1) sr(-1) with spectral index Gamma = 2.4(-0.4)(+0.5) .The null cosmic flux assumption is rejected with a significance of 1.6 sigma .nonenoneAlbert A; Andre M; Anghinolfi M; Anton G; Ardid M; Aubert JJ; Aublin J; Avgitas T; Baret B; Barrios-Marti J; Basa S; Belhorma B; Bertin V; Biagi S; Bormuth R; Bourret S; Bouwhuis MC; Branzas H; Bruijn R; Brunner J; Busto J; Capone A; Caramete L; Carr J; Celli S; El Moursli RC; Chiarusi T; Circella M; Coelho JAB; Coleiro A; Coniglione R; Costantini H; Coyle P; Creusot A; Diaz AF; Deschamps A; De Bonis G; Distefano C; Di Palma I; Domi A; Donzaud C; Dornic D; Drouhin D; Eberl T; El Bojaddaini I; El Khayati N; Elsasser D; Enzenhofer A; Ettahiri A; Fassi F; Felis I; Fusco LA; Gay P; Giordano V; Glotin H; Gregoire T; Ruiz RG; Graf K; Hallmann S; van Haren H; Heijboer AJ; Hello Y; Hernandez-Rey JJ; Hossl J; Hofestadt J; Illuminati G; James CW; de Jong M; Jongen M; Kadler M; Kalekin O; Katz U; Kiessling D; Kouchner A; Kreter M; Kreykenbohm I; Kulikovskiy V; Lachaud C; Lahmann R; Lefevre D; Leonora E; Lotze M; Loucatos S; Marcelin M; Margiotta A; Marinelli A; Martinez-Mora JA; Mele R; Melis K; Michael T; Migliozzi P; Moussa A; Navas S; Nezri E; Organokov M; Pavalas GE; Pellegrino C; Perrina C; Piattelli P; Popa V; Pradier T; Quinn L; Racca C; Riccobene G; Sanchez-Losa A; Saldana M; Salvadori I; Samtleben DFE; Sanguineti M; Sapienza P; Schussler F; Sieger C; Spurio M; Stolarczyk T; Taiuti M; Tayalati Y; Trovato A; Turpin D; Tonnis C; Vallage B; Van Elewyck V; Versari F; Vivolo D; Vizzoca A; Wilms J; Zornoza JD; Zuniga JAlbert, A; Andre, M; Anghinolfi, M; Anton, G; Ardid, M; Aubert, Jj; Aublin, J; Avgitas, T; Baret, B; Barrios-Marti, J; Basa, S; Belhorma, B; Bertin, V; Biagi, S; Bormuth, R; Bourret, S; Bouwhuis, Mc; Branzas, H; Bruijn, R; Brunner, J; Busto, J; Capone, A; Caramete, L; Carr, J; Celli, S; El Moursli, Rc; Chiarusi, T; Circella, M; Coelho, Jab; Coleiro, A; Coniglione, R; Costantini, H; Coyle, P; Creusot, A; Diaz, Af; Deschamps, A; De Bonis, G; Distefano, C; Di Palma, I; Domi, A; Donzaud, C; Dornic, D; Drouhin, D; Eberl, T; El Bojaddaini, I; El Khayati, N; Elsasser, D; Enzenhofer, A; Ettahiri, A; Fassi, F; Felis, I; Fusco, La; Gay, P; Giordano, V; Glotin, H; Gregoire, T; Ruiz, Rg; Graf, K; Hallmann, S; van Haren, H; Heijboer, Aj; Hello, Y; Hernandez-Rey, Jj; Hossl, J; Hofestadt, J; Illuminati, G; James, Cw; de Jong, M; Jongen, M; Kadler, M; Kalekin, O; Katz, U; Kiessling, D; Kouchner, A; Kreter, M; Kreykenbohm, I; Kulikovskiy, V; Lachaud, C; Lahmann, R; Lefevre, D; Leonora, E; Lotze, M; Loucatos, S; Marcelin, M; Margiotta, A; Marinelli, A; Martinez-Mora, Ja; Mele, R; Melis, K; Michael, T; Migliozzi, P; Moussa, A; Navas, S; Nezri, E; Organokov, M; Pavalas, Ge; Pellegrino, C; Perrina, C; Piattelli, P; Popa, V; Pradier, T; Quinn, L; Racca, C; Riccobene, G; Sanchez-Losa, A; Saldana, M; Salvadori, I; Samtleben, Dfe; Sanguineti, M; Sapienza, P; Schussler, F; Sieger, C; Spurio, M; Stolarczyk, T; Taiuti, M; Tayalati, Y; Trovato, A; Turpin, D; Tonnis, C; Vallage, B; Van Elewyck, V; Versari, F; Vivolo, D; Vizzoca, A; Wilms, J; Zornoza, Jd; Zuniga,

All-flavor Search for a Diffuse Flux of Cosmic Neutrinos with Nine Years of ANTARES Data

The ANTARES detector is at present the most sensitive neutrino telescope in the northern hemisphere. The highlysignificant cosmic neutrino excess observed by the Antarctic IceCube detector can be studied with ANTARES,exploiting its complementing field of view, exposure, and lower energy threshold. Searches for an all-flavor diffuseneutrino signal, covering nine years of ANTARES data taking, are presented in this Letter. Upward-going eventsare used to reduce the atmospheric muon background. This work includes for the first time in ANTARES bothtrack-like (mainly nm) and shower-like (mainly ne) events in this kind of analysis. Track-like events allow for anincrease of the effective volume of the detector thanks to the long path traveled by muons in rock and/or sea water.Shower-like events are well reconstructed only when the neutrino interaction vertex is close to, or inside, theinstrumented volume. A mild excess of high-energy events over the expected background is observed in nine yearsof ANTARES data in both samples. The best fit for a single power-law cosmic neutrino spectrum, in terms of perflavorflux at 100 TeV, is φ01f100 TeV (1.7±1.0) × 10-18GeV-1 cm-2 s-1 sr-1 with spectral index γ=2.4-0.4+0.5. The null cosmic flux assumption is rejected with a significance of 1.6δ

THE FIRST COMBINED SEARCH for NEUTRINO POINT-SOURCES in the SOUTHERN HEMISPHERE with the ANTARES and ICECUBE NEUTRINO TELESCOPES

We present the results of searches for point-like sources of neutrinos based on the first combined analysis of data from both the ANTARES and IceCube neutrino telescopes. The combination of both detectors, which differ in size and location, forms a window in the southern sky where the sensitivity to point sources improves by up to a factor of 2 compared with individual analyses. Using data recorded by ANTARES from 2007 to 2012, and by IceCube from 2008 to 2011, we search for sources of neutrino emission both across the southern sky and from a preselected list of candidate objects. No significant excess over background has been found in these searches, and flux upper limits for the candidate sources are presented for E -2.5 and E -2 power-law spectra with different energy cut-offs

Joint Constraints on Galactic Diffuse Neutrino Emission from the ANTARES and IceCube Neutrino Telescopes

The existence of diffuse Galactic neutrino production is expected from cosmic-ray interactions with Galactic gas and radiation fields. Thus, neutrinos are a unique messenger offering the opportunity to test the products of Galactic cosmic-ray interactions up to energies of hundreds of TeV. Here we present a search for this production using ten years of Astronomy with a Neutrino Telescope and Abyss environmental RESearch (ANTARES) track and shower data, as well as seven years of IceCube track data. The data are combined into a joint likelihood test for neutrino emission according to the KRAg model assuming a 5 PeV per nucleon Galactic cosmic-ray cutoff. No significant excess is found. As a consequence, the limits presented in this Letter start constraining the model parameter space for Galactic cosmic-ray production and transport