Aart Heijboer

Exploring the Cosmoswith Neutrinos…all of them.

vidi interview 14 mei 2008

Why look for High Energy Cosmic Neutrinos?

To study the universe at high energies, neutrinos are the ideal messenger particle,

not absorbed in the source or on their way to Earthnot deflected by magnetic fields: point back to the source

What is the physics of the most energetic objects in the universe? (Gamma Ray Bursts, Supernova remnants, Active Galactic Nuclei). What is the origin of high energy cosmic rays?

What is the nature of the Dark Matter?

Big, open questions:proton(cosmic ray)

How to detect Cosmic Neutrinos?

Proposed research will be carried out with two European projects: ANTARES: uses 200x200x400 m3 of Mediterranean Sea water – nearing completion. KM3NeT: will be at least 1x1x1 km3. In R&D phase.

Antares and its first neutrinos

Upgoing muon detected (Atmospheric background) muon-neutrino

Neutrino flavour mixing

Neutrinos come in three types (or flavours): and

Observations of atmospheric and Solar neutrinos have showed that neutrinos have a tiny mass and change flavour.

Implication for neutrino telescopes: Even though the source produces (mostly) , on Earth all flavours are equally abundant

proposal:

Develop methods to detect e and

and use them to complement to maximizediscovery potential of Antares and KM3NeT

And use them to search for neutrinopoint sources.

e

Event signatures

Eµ=10 TeV

muon

e

electronshower

long track, not contained single localized 'shower' ‘double bang’

tau leptondecays

We will develop the data-analysis (reconstruction) software to exploit the information from all signatures.

Event signatures

Eµ=10 TeV

muon

e

electronshower

long track, not contained single localized 'shower' ‘double bang’

tau leptondecays

We will develop the data-analysis (reconstruction) software to exploit the information from all signatures.

double bang

e

direction resolution

energy resolution

detection rate

background

-

+

-

+

++

-

+

--

+

+

-

++

e and have low background

and great energy resolutionenergy resolution is crucial tostudy the spectra which conveythe physics of the sources.

Looking for point sources

Sky plot of one year of atmospheric muon neutrinos

A neutrino sourceor a random clusterof atmospheric background neutrinos?

Looking for point sources

A neutrino sourceor a random clusterof atmospheric background neutrinos?

+

e

Even a few e and could

resolve the question!

Will develop the methodsto classify events and combine them in a single events from different neutrino types

Summary

Propose to exploit electron and tau neutrinos in addition to muon neutrinosNew capabilities will benefit experiments as a whole (opportunities to collaborate)Enhanced study of the source spectra & enable -mixing measurements

My group will use these methods to perform the most sensitive search for cosmic sources of neutrinos with Antares

Very high-profile measurementOptimal chance of discovering the first cosmic neutrino source!

Relevant experience: Developed search method and reconstruction currently used in ANTARES.

Still well known (and occasionally active) → flying start.Combining measurements & statistics: Bs-mixing at CDFOpening up new channels: Higgs search at CDF.Leadership, fruitful collaboration on large and small scales.

Now is the timeAntares will be completed in a few weeks!Crucial input needed soon to decide KM3NeT design.

Thank you for your attention.

Added power and science potential

Energy resolution is crucial: background has know, very steep spectrum spectra convey the physics!

Tau Neutrino Signatures in IceCube: Overview

Cartoon

Inverted lollipop but low-E tau decays quickly to ; Study ratio Esh/Etr

Low E Lollipop

Double bang, w/cascades un-resolvable, but nearby DOM(s) see double pulsed waveform

Double Pulse

Tau created and decays inside, cascades well-separatedDouble Bang

Tau created outside (un- detected), decaysmuon, see in light level along track

Sugardaddy(see talk by T. DeYoung)

Tau created insidecascade, decays outside (undetected)Inverted Lollipop

Tau created outside (un- detected), decayscascadeLollipop

DescriptionSignature

DOM Waveform

here, just about half the eventsare reconstructed as up going:=> reco is not doing anything useful(we're not even sure these events are muons at all... could be random k40)

To very good approximation: true fraction of upgoing events is zero.Let's use this fact to our advantage for a change

=> See how well reconstruction measures the number of up-going events

here, (only) about 1% of events are reconstructedin wrong hemisphere.

Is the muon reconstruction working?

5 string data

will discussthese later