Diffuse neutrino flux J. Brunner CPPM ESA/NASA/AVO/Paolo Padovani

Neutrino Spectrum on Earth Close to a nuclear power plant GRB,SNR Snap-hook

Diffuse Neutrino Spectrum GRBs

Diffuse Neutrino Spectrum Remnant from ~1min after Big Bang Non-relativistic speed (at least 2 & 3) No direct detection method known SNR, etc.

Diffuse Neutrino Spectrum Integrated flux from nuclear fusion of all stars Spectrum similar to solar neutrino Did not find any flux estimates SNR, etc.

Diffuse Neutrino Spectrum Integrated flux from core-collapse SuperNovae Limits from Underground Experiments (SK) Tuesday session GRBs

Diffuse Neutrino Spectrum Diffuse flux at TeV energies This talk GRBs

Neutrino Flux components @ TeV-PeV energies Conventional flux from  & K decay () ~ 20 (e) soft  ~ E-3.7 Harder spectrum from prompt  from c,b-meson decay  ~ E-2.7 Astrophysical neutrinos:  ~ E-2  ~ E-2 figure: courtesy IceCube

Diffuse astrophysical neutrinos Flux of Cosmis Rays Extragalactic origin otherwise not diffuse AGNs & GRBs Upper bound (W&B) derive  flux from CR-flux CR (mainly protons) from neutrons which escape acceleration site (n-transparent) Other models “opaque” sources try to avoid this bound

Experimental results Recent publication Atmospheric neutrinos () IC40 atmospheric neutrinos Phys. Rev. D 83 (2011) 012001 Diffuse flux search with Cascades (x) 5 years Amanda Astropart. Phys. 34 (2011) 420-430 IC22 (submitted PhysRev) arXiv:1101.1692 (astro-ph.HE) Diffuse flux search with tracks () IC40 arXiv:1011.5027 (astro-ph.HE) Antares Phys. Lett. B 696 (2011) 16-22

Analyzed data sets 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Amanda 1001days IC22 257 days IC40 359 days ANTARES 334 days Better understanding of apparatus  delay between data taking and publication gets shorter

Studies in the Muonic channel Easy to reject down-going atm. Muons from tracking Precision of E at detector at highest energies only factor ~2 (0.3 in lg(E)) Conversion of to E depends on flux Neutrino Telescope  Muon track at TeV/PeV energies significantly longer than detector size Hadronic shower Stochastic energy loss (e.g. bremsstrahlung)  Vertex mostly outside detector volume

IceCube-40 atmospheric  ~18000 upward-going events in final sample Regularized unfolding from dE/dx variable Uncertainties increase with energy Zenith angle distribution Uncertainties OM & Ice Zenith angle effects Unfolding method

Atmospheric  flux PRELIMINARY 3 measurements from Amanda and IC40 are compatible 2 Methods used Forward folding Unfolding Compatible with Honda flux Within errors no choice between conventional models possible PRELIMINARY L. Gerhardt, Trento, Dec2010

Test of prompt flux component No sign of prompt neutrinos seen so far there should be an “ankle” in the  spectrum Several high predictions can be constrained Notably RQPM PRELIMINARY 3 2 90% S. Grullon L. Gerhardt, Trento, Dec2010

ANTARES search for diffuse flux Data sample Dec 2007- to Dec 2009 first result from 2 years of data with (almost) complete detector 335 days active R: energy estimator based on hit multiplicity on PMTs Good correlation with true muon energy observed R>1.31 : 90% of expected signal between 20 TeV and 2 PeV

Antares - Results 9 events in final sample conventional atm. : 8.7 , Conventional  + prompt (RQPM) 10.7 Prompt  (RQPM) E-2 flux at limit No excess @ high energy Not sensitive to prompt component Limit for astrophysical flux

Brightest Neutrino in the sample height E~80 TeV time

ANTARES - Result E2F(E)90%= 5.3 10-8 GeV cm-2 s-1 sr-1 20 TeV<E<2.5 PeV 90% C.L. upper limit assuming E-2 flux spectrum At time of publication (Sep 2010) world best limit on diffuse flux ! Physics Letters B696 (2011) 16-22.

Study in the Cascade channel Same topology for NC and e-- CC interactions ignore here “double bang” signature for E > 10 PeV When using containment condition: E measured calorimetric Precision 10-20% possible Problem: background from showers from down-going muons Neutrino Telescope  atm  Shower Vertex mostly inside detector volume bremsstrahlung

IC22 Cascades 257 days of data taking Good agreement data with (normalized) atmospheric muon MC So far no clean sample of atmospheric -cascade events could be isolated

IC22 cascades Final sample (after energy cut) 14 (shower) events above 16 TeV MC: 8.3 +/- 3.6 Limit per flavour (all-flavour/3) E2(E)90%= 1.2 10-7 GeV cm-2 s-1 sr-1

Summary of results Baikal NT-200 (e++)/3 Amanda II UHE (e++)/3 IC22 (e++)/3 Amanda 00-04 (e++)/3

Summary of results Cascade limits cluster around 10-7 Baikal NT-200 (e++)/3 Amanda II UHE (e++)/3 IC22 (e++)/3 Amanda 00-04 (e++)/3 Cascade limits cluster around 10-7 No cascade  seen so far

Summary of results Antares 07-09 Best published limit Baikal NT-200 (e++)/3 Amanda II UHE (e++)/3 IC22 (e++)/3 Amanda 00-04 (e++)/3 Antares 07-09 Best published limit

Summary of results IC40 : best Preliminary limit Baikal NT-200 (e++)/3 Amanda II UHE (e++)/3 IC22 (e++)/3 Amanda 00-04 (e++)/3 IC40 : best Preliminary limit

Summary of results IC40 5 excluded

Conclusion Wealth of new results for diffuse neutrino fluxes from IceCube & ANTARES Fast publication of results now standard Start to test realistic models Detection of prompt atmospheric neutrinos &/or astrophysical fluxes in reach Stay Tuned !

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