CEA DSM Irfu

The ANTARES Neutrino TelescopeA status report

Niccolò Cottinion behalf of the ANTARES Collaboration

44th Rencontres de Moriond February 2009

05 / 02 / 2009 Niccolò Cottini 2CEA DSM Irfu

The ANTARES Collaboration

• Since 1996• 7 countries• 22 laboratories• 200 physicists,

engineers, sea scientists

05 / 02 / 2009 Niccolò Cottini 3CEA DSM Irfu

Outline of the talk

• Neutrino astronomy– The potential sources

• The ANTARES detector– Construction milestones

• Detector operations– The data taking campaign

• The first physics analyses– Atmospheric muons– Atmospheric neutrinos– Search for cosmic neutrino sources– Indirect dark matter detection

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The Neutrino Astronomy

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Neutrino astronomy

p

Galaxy

Local galaxy group

p/A + p/ +0+

e e

• : interact with CMB and matter

• Protons: deflection by magnetic fields

• : weakly interacting

– huge target needed (100Mton - Gton)

05 / 02 / 2009 Niccolò Cottini 6CEA DSM Irfu

Potential sources

GALACTIC

Supernova remnants

Pulsars

Microquasars

EXTRAGALACTIC

GRBs

AGNs

Indirect dark matter search

See Damien Dornic’s talk

See Vincent Bertin’s talk

05 / 02 / 2009 Niccolò Cottini 7CEA DSM Irfu

Detection principle

43°

interaction

Sea floor

Cherenkov light from

3D PMTarray

Main detection channel: charged interaction giving an ultrarelativistic

Energy threshold: 10 GeV

ANTARES 12 lines MC

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The ANTARES detector

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The ANTARES site

• 42°50’ latitude Nord• 6°10’ longitude Est

• Galactic Center– visible 75% of the day

Galactic coordinates

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Toulon

La Seyne

Submarine cable (~40km)

Shore Station

The ANTARES site

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The ANTARES detector

~60 m

100 m

350 m

14.5 m

Link cable

JunctionBox

Cable toshore

2500m depth

05 / 02 / 2009 Niccolò Cottini 12CEA DSM Irfu

The ANTARES detector

Storey

45°

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Hydrophone

17’’ glass sphere10’’ PMT

A detector storey

DAQSlow Control

Titanium frame

LED Beacon

~10 cm resolution

~0.6 ns resolution

05 / 02 / 2009 Niccolò Cottini 14CEA DSM Irfu

2006 – 2008: deployments of the detector lines

• Line 1: 03 / 2006

• Line 2, 3, 4, 5: 01 / 2007

• Line 6, 7, 8, 9, 10: 12 / 2007

• Line 11, 12: 05 / 2008

~60 m

05 / 02 / 2009 Niccolò Cottini 15CEA DSM Irfu

Detector layout

See Kay Graf’s talk

Acoustic storey

… and several instruments for environment studies with the ANTARES infrastructure

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Detector operations

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The detected signal

• Muon (Cherenkov)– 2 µs crossing time

• 40K decay– Continuous background

30 kHz *

• Bioluminescence– Continuous background

30 kHz *– Occasional bursts ~MHz

Simulation

2 min

* 10’’ PMT, 0.3 p.e. threshold

792 days

05 / 02 / 2009 Niccolò Cottini 18CEA DSM Irfu

The Trigger

• Front end chip digitizes charge and time of a light signal

• All data transmitted through multiplexed Gigabit links

– the whole data flow can not be written to disk

• Computer farm running a software trigger:

– look in all directions for light signals compatible with a muon track

– when found, write a Physics Event

• Other triggers exist: cluster of storeys, GRBs, Galactic Center, …

“ALL DATA TO SHORE” SCHEME:

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Track reconstruction

=35o

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Number of triggers

10 or more lines (2008)5 lines (2007)

Data taking ongoing……accumulating neutrinos

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The first physics analyses

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atmospheric

atmospheric

Atmosphere

Sea

Earth

cosmic

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Muon flux at the detector

Atmosphere

Earth

Sea

107 atmospheric per year*103 atmospheric

per year*

cosmic

Line 1: 03 / 2006

Line 2, 3, 4, 5: 01 / 2007

Line 6, 7, 8, 9, 10: 12 / 2007

Line 11, 12: 05 / 2008

Performance paper submitted

First physics analyses completed

Ongoing analysis

Data taking

* Reconstructed tracks in 12 line detector

05 / 02 / 2009 Niccolò Cottini 24CEA DSM Irfu

Atmospheric muon studies with 5 lines

• Systematic uncertainty ± 30%• Main contributions

– optical module response– absorption length of the light in water

See Claire Picq’s talk

data

CORSIKA (QGSJET01) + NSU model

MC uncert.

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Selection of neutrino events with 5 lines

Upgoing events dominated by the tail of badly reconstructed atmospheric muons

Upgoing events Downgoing events

Data, MC, MC (x100)

Likelihood ratio

: maximum likelihood of the track fit

MC

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Data, MC, MC (x100)

Selection of neutrino events with 5 lines

Purity = ~90%; Efficiency = ~30%

y = s(x) / [ s(x) + b(x) ]

05 / 02 / 2009 Niccolò Cottini 27CEA DSM Irfu

Detection of atmospheric neutrinos with 5 lines

)()(4)(41218 342 syststattheor

Data : 185 (1,1 / j), 93% purity

ANTARES 5 lines (164 days live time)

MC :

• Test of detector response to a known neutrino signal

• A preliminary step before searching for cosmic sources

Bartol flux (20% uncertainty on the absolute flux)

Mainly optical module response and calibration uncertainties (preliminary)

DataMCUncertainties

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Search for point like neutrino sources with 5 lines

See Katia Fratini’s talk

No discovery 90% CL flux limit

• Definition of a potential source list

• Analysis optimization by MC, for E-2 flux

• Data unblinding: 94 neutrino events

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Preliminary analysis of 10 line data

208 neutrinos

Preliminary quality cuts

Dec 2007 – Apr 2008 : 100 days live time

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A neutrino event on 12 lines

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Conclusion

• ANTARES today

– Successful end of construction phase

• Technology proven

• Data taking ongoing

– First physics outputs

• Atmospheric and , cosmic neutrino sources, dark matter

• Neutrino oscillations, magnetic monopoles, VHE neutrino interactions, …

• On the road for the next step

– KM3Net…

KM3See Christopher Naumann’s talk

05 / 02 / 2009 Niccolò Cottini 32CEA DSM Irfu

Vue de la salle de contrôle d’ANTARESA view from ANTARES control room