Results from the ANTARES Deep Sea Neutrino Telescope

Transcription

1 Stockholm Results from the ANTARES Deep Sea Neutrino Telescope Maurizio Spurio On behalf of the ANTARES Collaboration Università di Bologna and INFN

2 Science with Deep Sea Neutrino Telescopes High energy neutrino astrophysics: galactic: SN, SNRs, m-quasars, molecular clouds, etc extra-galactic: AGNs, GRBs, choked-grbs, GZK, etc... Search for New Physics: Dark matter (Sun, Galatic Centre), Monopoles, nuclearites,?? Earth-Sea Science: oceanography, sea biology, seismology, environmental monitoring... SNR oscillations dark matter m-quasars GRBs magnetic Fermi-bubbles monopole GeV-100 GeV GeV-TeV TeV-PeV PeV-EeV > EeV 2

3 Stockholm 3 Neutrinos and Multi-Messenger Astronomy Protons/ Cosmic Rays: Detected on Earth up to extremely high energies: 10 8 TeV Hard to study sources due to deflection by magnetic fields Photons: Produced in leptonic (synchrotron, IC) and hadronic ( 0 ) processes Absorbed at higher energies and large distances Neutrinos (and GW): Unambiguous signature of hadronic acceleration Not deflected by magnetic fields or absorbed by dust Horizon not limited by interaction with CMB/IR Can escape from region of high matter density Can be time correlated with optical signals hadronic accelerators exist, but where? leptonic vs hadronic models identify Galactic and extragalactic cosmic ray sources

4 Stockholm Cosmic Rays, photons and neutrinos Hadronic cascades (as for atmospheric showers) p/a + p/ m m e e m m m e e m e : m : =1:2:0 source oscillatio ns e : m : =1:1:1 Earth Primary acceleration («Bottom-Up») Stochastics shocks (Fermi mechanism) Explosion /Accretion / Core collapse Benchmark Extra Gal. flux Waxman-Bahcall ~ 500 events /yr/ km 2 But HE also from electromagnetic processes Synchrotron Inverse Compton

5 Detection Principle p, a m m p 3D PMT array m Cherenkov light from m m 42 Sea floor m m interaction The reconstruction is based on local coincidences compatible with the Cherenkov light front - Main channel: m interaction giving an ultra-relativistic m ( e and also) - Energy threshold ~ 20 GeV- 24hr operation, more than half sky coverage 5

6 Stockholm Physical Background sources Atmospheric muons: only downgoing Shield detector & reject downward goingmuons Atmospheric m 10 9 per year Atmospheric 10 4 per year Cosmic 0-10 per year? upgoing downgoing T. Chiarusi, M.S. Eur. Phys. Journal C (2010) arxiv:

7 The ANTARES Collaboration IFIC, Valencia UPV, Valencia UPC, Barcelona University of Erlangen NIKHEF, Bamberg Observatory Amsterdam Univ. of Wurzeburg Utrecht KVI Groningen NIOZ Texel ITEP,Moscow Moscow State Univ ISS, Bucarest CPPM, Marseille DSM/IRFU/CEA, Saclay APC, Paris LPC, Clermont-Ferrand IPHC, Strasbourg Univ. de H.-A., Mulhouse LAM, Marseille COM, Marseille GeoAzur Villefranche INSU-Division Technique LPRM, Oujda Univ./INFN of Bari Univ./INFN of Bologna Univ./INFN of Catania LNS Catania Univ./INFN of Pisa Univ./INFN of Rome Univ./INFN of Genova 8 countries 31 institutes ~150 scientists+engineers 7 7

8 The ANTARES Site & Infrastructure -2475m Shore Station IFREMER Toulon Centre 40 km submarine cable FOSELEV Marine 8

9 Stockholm The ANTARES Detector 2500m ~20 Mton instr vol inch PMTs 12 lines 25 storeys/line 3 PMTs / storey 450 m 40 km to shore Junction Box 70 m Interlink cables

10 : Building phase of the Detector ~70 m Junction box 2001 Main cable 2002 Line 1, Line 3, 4, 5 01 / 2007 Line 6, 7, 8, 9, / 2007 Line 11, /

11 Earth and Sea Sciences Connected 30 Oct 2010 Secondary Junction Box O2, CTD, P Seismograph Turbidity BioCam Currentmeter Instrumentation module 11

12 Up- and down-going Events reconstructed up-going neutrino detected in 6/12 detector lines: reconstructed down-going muon detected in all 12 detector lines: 12

13 Region of Sky Observable by Neutrino Telescopes IceCube (South Pole) ANTARES(43 North) Mkn 421 Mkn 501 Mkn 501 CRAB RX J CRAB SS433 SS433 GX339-4 VELA Galactic Centre Emphasis on study of Galactic sources 13

14 Selected ANTARES physics results 1. Cosmic sources searches 2. Diffuse flux from ExtraGalactic sources 3. Multimessenger approach and Gravitational Waves coincidences 4. Neutrino oscillations 14

15 1. Point Source Search Neutrino candidates: Upgoing particles Background for neutrinos: mis-reconstructed atmospheric muons Track fit quality used to reject mis-reconstructed downgoing muons Number of hits used as estimator of muon (~neutrino) energy upgoing Number of up-going events as a function of the track quality parameter L Angular distribution of wellreconstructed tracks 15

16 1. Angular Resolution for Neutrinos m Full 12 line detector cumulative distribution of the angle between the true neutrino track and the reconstructed muon event (assuming E -2 spectrum). The median is % of the events within 1 16

17 Stockholm 1. Full-Sky Search ( ) Sky map in equatorial coordinates (3058 candidates) Pre-trial prob Most significant cluster at: RA= 46.5, δ= ⁰ 3⁰. Results compatible with the background hypothesis N sig = 5 p-value=0.026 (post-trial) Significance = 2.2 σ

18 Stockholm 1. Source Candidate List Look in the direction of a list of 51 predefined candidate sources (selection of sources mostly based on γ-ray flux and visibility) First eleven sources sorted by p-value. Last column shows the 90% CL upper limit on the flux (E / GeV) -2 GeV -1 cm -2 s -1 HESS J most signal-like, p value 41% (post trial) Compatible with the background hypothesis

19 Stockholm 1. Candidate List Search 90%CL Limits ANTARES 2016 Assumes E -2 flux for a possible signal ANTARES has the most stringent limits for the Southern Sky Galactic sources expected to have energy cutoff- not visible to IceCube 2016: expect limits to improve by another factor ~2.5

20 2. Diffuse m flux Phys. Lett. B696 (2011) E 2 F(E) 90% = GeV cm -2 s -1 sr TeV<E<2.5 PeV IC40 20

21 2. Search for diffuse from Fermi Bubbles Fermi-LAT data provided evidence of the emission of HE rays with a high intensity E -2 spectrum from two large areas above and below the Galactic Center (the "Fermi bubbles"). A hadronic mechanism has been proposed for this rays emission making the Fermi bubbles promising sources of high-energy neutrinos For 100% hadronic models: E 2 df /de=1.2*10-7 GeV cm -2 s -1 sr -1 E cutoff protons: 1PeV-10 PeV Galactic coords Background estimated from average of three OFF regions (time shifted in local coordinates) Detector coords 21

22 2. Search for Neutrinos from Fermi Bubbles Live time = 588 days Cuts optimised for best MRF and a cutoff at 100 TeV ANTARES preliminary ON ZONE <OFF ZONE> N back (OFF) = 90±5(stat)±3(sys) N signal (ON) = 75 No signal exclude fully hadronic FB model without cutoff (90%CL F&C) Future: full dataset and improved energy estimator ANTARES preliminary 50 TeV cutoff 100 TeV cutoff 500 TeV cutoff no cutoff dotted: model prediction solid: 90% CL limits 22

23 3. Multimessenger approach Strategy: higher discovery potential by observing different probes higher significance by coincidence detection higher efficiency by relaxed cuts MoUs for joint research Alerts Ligo/Virgo Gravitational waves: trigger + dedicated analysis chain TAROT ROTSE optical follow up: arxiv: Astropart.Phys.35(2012) arxiv: GCN GRB Coord. Network: γ satellites arxiv:

24 3. Search for GW coincident signal V. V. Elewyck et al. Int.J.Mod.Phys. D18 (2009) B. Baret et al. Astropart.Phys. 35 (2011) 1-7 B. Baret et al. arxiv: Common data taking Search strategy Done On going Instantaneous Antares+Ligo+Virgo common view

25 Dataset Analysis set limits on distance of occurrence of NS-BH and NS-NS mergers Sub-optimal detectors No dedicated optimisation NO DETECTION Distance within which there is a 90% detection probability with a 1% false alarm rate per neutrino I. Di Palma et al. TAUP 2011 B. Bouhou et al. arxiv:

26 Stockholm 3. Correlation with Gravitational Waves - plausible common sources (microquasars, SGR, GRBs) - discovery potential for hidden sources (e.g. failed GRBs) 2007 ANTARES 5-line detector line detector adv LIGO/VRIGO 2007: No statistical significant correlation set limits on distance of occurrence of NS-BH and NS-NS mergers First joint ANTARES/LIGO/VIRGO publication: arxiv: v : expect to constrain fraction of star collapses accompanied by coincident emission of jets beamed towards Earth 26

27 Stockholm 4. Oscillations with Atmospheric Neutrinos L=2 R Earth cos, from track fit E from muon range E <100 GeV Oscillations maximal at E =24 GeV for vertical neutrinos Dashed line: oscillation effect Larger effect on single-line (low energy) than multi-line (higher energy) events MC truth 27

28 Stockholm 3. Neutrino Oscillations: Track Selection zenith angle resolution: 0.8 degrees for multi-line events 3 degrees for single-line events Multi-line Single-line Select pure sample of atmospheric neutrinos (<5% muon contamination) using a cut on the track fit quality Blue: misreconstructed atmospheric muons Green: atmospheric neutrinos Red: neutrino with oscillations

29 Stockholm 3. Neutrino Oscillations: Result data (863 days): No oscillation: 2 /NDF = 40/24 (2.1%) Best fit: 2 /NDF = 17.1/21 Δm 2 = ev 2 sin 2 2 =1.00 ANTARES preliminary no osc Systematics: (Absolute normalisation free) Absorption length: ±10% Detector efficiency: ±10% Spectral index of flux: ±0.03 OM angular acceptance ANTARES preliminary 68%CL contours 5% error on slope vs E R /cos R best osc ANTARES K2K Super-K MINOS Assuming maximal mixing: Δm 2 =(3.1±0.9) 10-3 ev 2 Accepted by PLB: arxiv:

30 Summary ANTARES infrastructure completed: Only operating deep sea neutrino telescope Largest neutrino telescope in the Northern hem. Operating smoothly, maintenance capability proven Good understanding of detector Important testbed for KM3NeT R&D and software Exciting and broad physics program. Unexplored regions of sensitivity for gal. sources Steady/transient sources, monopoles, DM, oscillations multi-messenger approach (optical, satellite, GW) Real-time readout and in-situ power capabilities a large program of multi-disciplinary activities: acoustics, biology, oceanography, seismology Major step towards the multi-kilometre cube deep-sea Neutrino telescope: KM3NeT 30

31 Spares 31

32 Counting Rates (short timescale) 2 min Continuous baseline: Radioactivity in the sea ( 40 K) + bioluminescent bacteria Bursts: bioluminescence from Macroscopic organisms 40 K K 20Ca e e 32

33 Acoustic Positioning Measure every 2 min: Distance line bases to 5 storeys/line and also storey headings and tilts Storey 1 Storey 8 Storey 14 Storey 20 Storey 25 Precision ~ few cms Radial displacement 33

34 Stockholm Absolute Pointing: Moon Shadow 884 days live time ( ) 2.7 sigma significance Agrees with Monte Carlo expectations 34