The ANTARES Underwater Neutrino Telescope

C. W. James, The ANTARES Underwater Neutrino Telescope, SEWM, Swansea, 13th July 2012 1

The ANTARES Underwater Neutrino Telescope

C.W. James, ECAP, University of Erlangen,

on behalf of the ANTARES collaboration.


Cosmic rays and neutrinos

• What produces this spectrum?

• Standard model: acceleration at relativistic astrophysical shocks

R. Shellard, Braz. J. Phys 31 (2001)


Why look for neutrinos?• Flux unattenuated over cosmological distances

Image courtesy of NRAO/AUI Nature 432 (2004) 75 Image courtesy of

NRAO/AUI

• Travel in straight lines (unlike cosmic rays)• Signatures of hadronic processes in the high-energy universe

SNR AGN jets and lobes GRB

NASA/Swift/Stefan Immler


Quick note: these are not Solar neutrinos!

• Production via cosmic-ray (~proton) interactions with:

• Much rarer than solar neutrinos – but more energetic (GeV-PeV: not MeV)– νμ and ντ CC interactions possible

low E proton

Hadronic matter (interstellar gas) Photon fields (CMB)


m

42°

interaction

Earth’s crust(sea floor; Antarctic continent)

Cherenkov light from m

3D PMTarray

nm

Main detection channel: nm CC interactions (nm NC, and ne and n also).

Detection Principle

nm

p

nm

nmmp, a

5

Optically transparent material(water; deep ice)


Let’s build it!

7

CPPM, Marseille DSM/IRFU/CEA, Saclay APC, Paris LPC, Clermont-Ferrand IPHC, Strasbourg Univ. de H.-A., Mulhouse LAM, MarseilleCOM, MarseilleGeoAzur Villefranche INSU-Division Technique

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

IFIC, Valencia UPV, Valencia UPC, Barcelona

NIKHEF, Amsterdam Utrecht KVI Groningen NIOZ Texel

ITEP,Moscow Moscow State Univ

University of Erlangen• Bamberg Observatory• Univ. of Wurzeburg

ISS, Bucarest

8 countries31 institutes~150 scientists+engineers LPRM, Oujda

The ANTARES Collaboration


ANTARES: Location

• 40km off the coast of Toulon


V. B

ertin

- CP

PM -

AREN

A'08

@ R

oma

The ANTARES detector

70 m

450 m

JunctionBox

Interlink cables

40 km toshore

2500m• 12 lines • 25 storeys/line• 3 PMTs / storey• 885 10-inch PMTs• 10-20 Mton volume


Sample events

• Maximum-likelihood fit to recorded photon hit times

http://www.pi1.physik.uni-erlangen.de/antares/online-display/online-display.php


ANTARES ‘visibility’

• ANTARES at 43o N• Sensitive to the Southern sky• Includes the Galactic Centre

Mkn 501

RX J1713.7-39

GX339-4SS433

CRAB

VELA

GalacticCentre

Visible

Invisible

ANTARES: 43o N

Never visible

Always visible

Incr

easi

ng se

nsiti

vity


n

m

ANTARES performance: angular resolution

• ~50% events reconstruct to better than 0.5o

• ~99% reconstruct to better than 10o

• Energy reconstruction is much harder (most is not ‘seen’)


Muon and neutrino backgrounds

• Remove atmospheric muon background with quality cuts

• CR neutrino background irreducible

1% misreconstruction

from below from above

pnmmp, a

Muo

n flu

x at

250

0m d

epth Look for an

excess here!


Science with ANTARES

• High-energy Neutrino Astrophysics– Galactic sources: SN & SNR, micro-quasars, CR in molecular clouds– Extra-galactic sources: AGN, GRB, GZK processes

• Search for new physics:– Dark matter annihilation, nuclearites, monopoles

• Earth sciences:– Oceanography, marine biology, seismology, environment monitoring…

GeV-100 GeV GeV-TeV TeV-PeV PeV-EeV > EeV

Oscillations DM SNR, μQSO AGN Exotics, GZK Marine biology

GUT???


Results!


All-sky point-source search

• Sky map in equatorial coordinates:– 2007-2010 data (813 days livetime)– 3058 candidates after cuts: expect 14% down-going muon contamination

Most significant cluster: 2.2σ

No strong evidence for a point-source excess


Search from suspected sources

• 51 pre-defined ‘suspect’ sources (mostly based on gamma-ray flux and visibility)

• Top 11 sources: most significant first

WR20a & b: hot, massive stars

HESS, Astronomy & Astrophysics 467 (2007) 1075


Neutrinos from gamma-ray bursts

• ‘Fireball’ model for GRBs:

– Explains long-duration bursts– Predicts neutrinos!

• Search criteria:– Direction (2o from source)– Time (~1 minute)– Upcoming events only

• Results from 2007 data (40 GRBs): no detection


Neutrino Oscillations

• Two-flavour mixing approximation:

– Measureable: ‘Unknown’: – World data: 1st minimum at , (120 m max muon range)

• Expectations for 863 days’ data:

Events seen with two lines

Events seen with one line

No oscillations

Best world data


Oscillation analysis: results

• After a Chi2 minimisation to and two systematic variables:

– 1st measurement of its type– Accepted July 2nd by Physics Letters B– Promising for next-generation larger detectors

DataNo oscillations

Best fit

Combined single and multi-line data ANTARESK2K

MINOSSuper-K

68% C.L.

90% C.L.


Search for Dark Matter Annihilation in the Sun

21

nPRELIMINARY

Angular distance from sun

• Lack of excess: => model limits (apologies: I do not have these plots here!)

• A search for an excess from the galactic centre is ongoing


Search for magnetic monopoles

• Relativistic monopoles emit VC radiation– 8550 times brighter than a muon– Look for extremely bright events!

• ANTARES search space– Relativistic – ‘intermediate mass’ (< 1014 GeV)

• Search performed on data from 2008:– 1 event– 0.13 bkgd– 1.5 σ significance


Multi-Messenger astronomy

Alerts

• Strategy:– Increase discovery potential (different probes)– Increase significance via coincidence

• Ligo/Virgo (grav. waves)– Dedicated analysis chain– GW trigger • GCN (GRB)

– Global burst network– GRB burst alert– ANTARES trigger and

coincident analysis

• TAROT (optical)– Follow-up search for SN– 10s repositioning


Summary

• ANTARES underwater neutrino telescope:– Largest neutrino telescope in the Northern Hemisphere– Proven ability to detect neutrino-induced muons– Good performance in bread & butter science: neutrino astrophysics– Sensitivity optimised for the galactic centre region

• Diverse physics program:– Dark matter– Neutrino oscillations– Exotics (magnetic monopoles, nuclearites)

• Entering ‘mature’ phase:– First round of results published (~1 year’s data)– Analyses on 3+ years of 12-line data in progress– More results on their way!


EXTRA SLIDES

(in case of tricky questions)


Background and diffuse flux sensitivity

• High energies favour source spectra– Background from atmospheric neutrinos: Enu

-3.7

– Sources: order Enu-2

• Look for a high-energy excess!E2F(E)90%= 5.3×10-8 GeV cm-2 s-1 sr-1

20 TeV<E<2.5 PeVEnergy estimation: the ‘R’ parameter

Limits on an E-2 flux


Standard data pipeline

• ‘hit’: send PMT data to shore when one or more photons are observed

• Raw data rate: too high to record• Trigger: Record data to disk if it looks `interesting’.• Standard trigger requirements:

– Large ( ) hits OR hits on neighbouring PMTs (600 Hz)– Clusters of >=5 hits– Trigger hits must be causally connected

• Many other triggers (GRB alert, monitoring info, GC etc)

Threshold: 0.3 Vphoton

PMT voltage

25 ns integration

Shore triggering and data acquisition


Candidate List Search – 90%CL Flux Limits

28

Assumes E-2 flux for a possible signal

ANTARES 2007-2010 813 days

ANTARES has the most stringent limits for the Southern Sky


• Bioluminescence: large seasonal fluctuations– Bacteria– Vertebrates

Optical Background

• Potassium 40 decay: constant background

Image courtesyWolfram Alpha

Spring 2006 Spring 2007


Trigger effective area

• (preliminary plot: officially updated version will be out shortly)


Data reduction for point-source search

• Cut on angular-error estimate, and on fit quality


Resolution: use the Moon’s shadow

• The Moon blocks CR: expect reduction in the upcoming-event rate

• 884 days’ livetime• 2.7 sigma defecit• Agrees with Monte Carlo expectations


Sea currents and acoustic positioning

Storey 1Storey 8

Storey 14Storey 20Storey 25

Radial displacement

Measure every 2 min:Distance line bases to 5 storeys/line

and also storeyheadings and tilts

Precision ~ few cms


2006 – 2008: Building phase of the Detector

• Junction box 2001• Main cable 2002• Line 1, 2 2006• Line 3, 4, 5 01 / 2007• Line 6, 7, 8, 9, 10 12 / 2007• Line 11, 12 05 / 2008

~70 m


Search for Neutrinos from Fermi Bubbles

For 100% hadronic models:Fn ~1/2.5 F (Vissani)E2dFn/dE=1.2*10-7 GeV cm-2s-1sr -1

E cutoff protons: 1PeV-10 PeV (Croker&Aharonian)E cutoff neutrinos = 1/20 cutoff protons

Background estimated from average of three ‘OFF’ regions (time shifted in local coordinates)

galactic coords detector coords


Dark Matter Simulation

MAIN

ANNIHILATION

CHANNELS

36

MWIMP = 350 GeV

τ leptons regeneration in the Sun mUED particular case…


Dark matter – detector performance

• ANTARES effective area to muon neutrinos incident on Earth– Most neutrinos do not produce detectable muons– Most muons are very low in energy


Magnetic Monopoles: data reduction

• Magnetic monopoles…– Theoretical prediction (quantisation of charge, guage theories…)– Have not been observed (various limits exist)– Have a magnetic charge g: will emit Vavilov-Cherenkov radiation– VC radiation: 8550 times brighter than that of a muon with similar velocity– Acceleration in cosmic magnetic fields


Search for Dark Matter Annihilation in the Sun

39

n

PRELIMINARY

Angular distance from sunPRELIMINARY

Documents

The ANTARES Underwater Neutrino Telescope