The High Energy Neutrino Sky as seen by Antares

Dorothea SamtlebenLeiden University / NIKHEF, Amsterdam

New windows to the Universe via high energy neutrinos

Particle Physics Atmosphere acts as ‘beam dump‘ for cosmic rays => Studies for - Prompt production (high energies) - Neutrino oscillations (low energies)

Dark Matter WIMPs accumulate in massive objects (Sun, Earth) => possibly annihilation signals observable,

Astrophysics

Neutrinos are valuable cosmic messengers coming undeflected from cosmic sources

Multimessenger approach exploited together withdetectors for electromagnetic radiation and gravitational waves

Neutrino sources Microquasars

Highly energetic particle acceleration needed to explainobserved cosmic ray energy spectrum

- g from inverse Compton scattering - g from synchrotron radiation of electrons - g from pion decay

Neutrino fluxes can be derived from g emission by assuming pion decay as origin of g

Xpp 0/ g

Xpp g/

gg

ee

SN1006Optical, radio, X-rays

Artist‘s view Artist‘s viewSupernova remnants

Gamma Ray Bursts

- Atmospheric neutrino flux ~ E-3

- Neutrino flux from cosmic sources ~ E-2

Mediterranean Field of View

> 75%> 25%

2 downward sensitivity assumed

5

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

Univ./INFN of Bari Univ./INFN of Bologna Univ./INFN of Catania LNS-Catania Univ. Napoli Univ./INFN of Pisa Univ./INFN of Rome Univ./INFN of Genova

IFIC, Valencia UPV, Valencia UPC, Barcelona

NIKHEF, Amsterdam Leiden Utrecht KVI Groningen NIOZ Texel

ITEP,Moscow Moscow State Univ

University of Erlangen• Bamberg Observatory• Univ. of Wurzeburg

ISS, Bucarest

8 countries34 institutes~150 scientists+engineers LPRM, Oujda

The ANTARES Collaboration

42°

interaction

Sea floor

Cherenkov light from

3D PMTarray

p

p, a

Cosmic rays interact with atmosphere => showers, muons, neutrinos

Neutrinos arrive from cosmic sources

Muon neutrino interaction in Earth => Muon passes detector

Also showers reconstructable => sensitive also to e,t

ANTARES detector

40 km toshore

• 12 lines mounted on the sea floor (2475m deep)• 25 storeys / line• 3 Photomultipliers / storey

PMTPMT

Track reconstruction

Quality of track fit can be used to decrease misreconstruction => Use likelihood value and angular error estimate

~105 atmospheric muons per day~5 atmospheric neutrinos per day

Maximum likelihood fit using hit positions and times(nanosecond resolution)

Track reconstruction

Track resolution degrees In point source analysis

Point source analysis

Analysis 2007-2010 data (813 days), 4 108 events, 3058 neutrino candidates

Skymap of p-values in equatorial coordinates

Most significant cluster, p-value=0.026 (α, δ) = (−46.5◦, −65.0◦) 5(9) events are within 1(3) degrees s (2.2s)

Ap J 760:53 (2012)

Flux limit• Study for 51 potential neutrino sources:

• No significant excess => upper limits

• Best limits for d<-30

Diffuse neutrino fluxData 2007-2009, corresponding to 335 active daysDistinction of diffuse flux from atmospheric neutrinos by energy (harder spectrum expected from sources)

Energy estimator R based on hit multiplicityon Photomultipliers

Simulation of energy estimator RDistribution of R in data in comparison to MC expectations

E-2 flux at limit

Prompt neutrinos (RPQM)

Diffuse neutrino flux

E2F(E)90%= 5.3 10-8 GeV cm-2 s-1 sr-1

20 TeV<E<2.5 PeV90% upper limit assuming E-2 flux spectrum

Physics Letters B 696 (2011) 16

Atmospheric neutrino spectrum

PRELIMINARY

E2F(E)90%= 3.2 10-8 GeV cm-2 s-1 sr-1

45 TeV<E<6.3 PeV90% upper limit assuming E-2 flux spectrum

2008-2011 data used

Two different energy estimators: - dE/dx as evaluated from charge collected in the detector - Combined likelihood for hit/no-hit for all OMs

L: lengthe: efficiency

Atmospheric energy spectrum by unfolding measuredspectrum

New diffuse limit using dE/dx estimator

Neutrinos from Fermi Bubble

15

Fermi Bubbles:• Excess of ɣ-rays seen in Fermi data in extended distinct regions (each ~ 25000 light-years)• Homogenous intensity • Sharp edges• Flat E-2 spectrum (between 1 and 100 GeV)

• Background estimated from average of 3 equivalent regions

• Event selection optimized for best model rejection factor

Galactic coordinates

Good visibility for ANTARES

Upper limits

16

Data 2008-2011 Fermi Bubbles zone: Nobs = 16

Excluding Bubbles zone: <Nbg> = 11 = (9+12+12)/3 No significant excess → set upper limits

50 TeV cutoff100 TeV cutoff500 TeV cutoff No cutoff

Solid: 90% CL limitsDotted: model prediction

ANTARES preliminary

Upper limits with respect to different models

PRELIMINARY

Dotted: different models

Search for Dark Matter

• Dark Matter WIMPs accumulate in heavy objects (Sun, Galactic Center, Earth)

• Capture/Annihilation in equilibrium at the Sun core

• Annihilation e.g. in bb/tt/WW -> +..

• Model-independent event simulation using WIMPSIM

• Interactions in the Sun and flavor oscillation, regeneration of t in the Sun taken into account

c

rc <sv>

Search for Dark Matter

c

rc <sv>

Neutrino candidates in the direction towards the sun (angular distance y)

kinematics

c2 based track reconstruction efficient for low energies

Different detector configurations

Angular resolution (median)

Spin-independent cross-section limit for ANTARES 2007-2008 in CMSSM

Dark Matter limits from the sun

For CMSSM:Branching ratios = 1(for WW, bb, ττ)(Large variation ofbranching ratios overparameter space)

PRELIMINARY

Dark Matter limits from the sunSpin-dependent cross-section limit for ANTARES 2007-2008 in CMSSM

For CMSSM:Branching ratios = 1(for WW, bb, ττ)(Large variation ofbranching ratios overparameter space)

PRELIMINARY

Neutrino oscillation

)cos16200(sin1

)27.1(sin1)(

2322

2322

Em

ELmP

• Low energy atmospheric neutrinos important

• Baseline L from zenith angle

• Energy estimate from track length

• Different track reconstruction using multi-line and single-line events (only zenith reconstructed)

Single LineMulti Line

Dashed: with oscillation

Simulation of reconstructed neutrinos

DataBest FitNo oscillations

Antares, K2K, Minos, SuperK

For maximal mixing

m2=(3.1±0.9) 10-3 eV2

PhysLettB 714, 224 (2012)

KM3NeT

First Funding already available to allowstart of construction

2013-15 Building/Deployment of first batch of detectors2015++ Completion of Detector

Deep Sea Research Infrastructure in the Mediterranean Sea hosting a multi cubic kilometer neutrino telescope

Locations of the three pilot projects:ANTARES: ToulonNEMO: Capo PasseroNESTOR: Pylos

860m

Track resolution 0.1deg @ TeV

New detector concept:Sphere with 31 PMTs - good directionality - single photon counting

Configuration

Multiple building blocks640 strings (in total)20 storeys/string=> 12800 DOMs

1 building block

860m

Track resolution 0.1deg @ TeV

New detector concept:Sphere with 31 PMTs - good directionality - single photon counting

Configuration

Multiple building blocks640 strings (in total)20 storeys/string=> 12800 DOMs

First light of sphere with 31 PMTs in Antares

Rate histogram for multiplicity of coincidences -> seeing first muons!

Neutrino telescope in seawater successfully established with high angular resolution

Variety of physics analyses underway, first results published

Large several cubic kilometer array Km3NeT planned in the Mediterranean Sea

Construction of first KM3NeT detection units underwayFirst light with new optical module in Antares!

=> NEW WINDOW TO THE UNIVERSE BECOMES AVAILABLE