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A M A N DA Antarctic Muon And Neutrino Detector Array. Status and Results. Peter Steffen DESY Zeuthen, Germany TAUP 2003. Draft.  150 members. The AMANDA Collaboration. Bartol Research Institute UC Berkeley UC Iivine Pennsylvania State UW Madison UW River Falls LBL Berkeley

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A M A N DA

Antarctic Muon And Neutrino Detector Array

Status and Results

Peter Steffen

DESY Zeuthen, Germany

TAUP 2003

Draft


The amanda collaboration

150 members

The AMANDA Collaboration

Bartol Research Institute

UC Berkeley

UC Iivine

Pennsylvania State

UW Madison

UW River Falls

LBL Berkeley

U. Simón Bolivar, Caracas

VUB, Brussel

ULB-IHEE, Bruxelles

U. de Mons-Hainaut

Imperial College, London

DESY, Zeuthen

Mainz Universität

Wuppertal Universität

Stockholm Universitet

Uppsala Universitet

Kalmar Universitet

South Pole Station

Antarctica

New Zealand

Venezuela (1)

USA (7+3)

Europe (10+1)

Japan

+ associated IceCube institutes in

USA, Europe, Japan, New Zealand


Contents
Contents

- Introduction

- cosmic muons

- atmospgeric neutrinios

- search for extraterrestial neutrinos:

-> diffuse flux of high energy

-> diffuse flux in the PeV to 100 PeV range

-> search for point sources

- search for neutrinos from WIMP annihilation

- other results: search for magnetic monopoles,

SN monitoring

cosmic ray composition

- Outlook

- search for GRB related neutrino burst (Kyler Kuehn)

- extension of AMANDA to ICE-CUBE (Shigeru Yoshida)


Physics motivation
Physics motivation

  • neutrino astronomy

  •  origin and acceleration of cosmic rays

  •  understand cosmic violent processes

  • (AGN, SNR, GRB, MQ, ....)

  • dark matter (neutralino annihilation)

  • - neutrino properties ( , cross sections ..)

  • search for magnetic monopoles

  • search for mini black holes


Neutrino source candidates

Supernova remnant

Microquasar

(SS433 etc.)

Active Galaxy

(optically dense, e.g. FRII)

 1 LJ

 106 LJ

Crab nebula

Black hole with

 mass of sun

Black hole with

108 x mass of sun

extra-galactic

galactic

Neutrino source candidates


Detection of e

O(km) long muon tracks

Electromagnetic and hadronic cascades

 15 m

~ 5 m

direction determination

by cherenkov light timing

Detection of e , ,


Detection of muon neutrinos

Above O(PeV): significant  absorption:

O(10 PeV)

O(TeV): use upward going muons

O(PeV): use horizontal events

O(10 PeV): use events from above

Detection of muon neutrinos

 (e)

Cosmic rays

 (e)

atmospheric muons

earth acts as shield


The Site

South Pole

AMANDA

Amundsen-Scott Station


Amanda ii and spase

optical

module

1996-2000

AMANDA-II and SPASE

South Pole Air Shower Experiment

inner 10 strings:

Amanda-B10

19 strings

677 PMTs

AMANDA II


Two events muon and cascade

200 TeV e candidate

Two events: muon and cascade


Detector capabilities

 effective area

(schematic):

-interaction in

earth, cuts

2 -5m2

En 2

3 cm2

100 GeV 100 TeV 100 PeV

Detector capabilities

  •  muons:

    • directional error: 2.0 - 2.5°

    • energy resolution:¶0.3 – 0.4

    • coverage: 2

  •  primary cosmic rays:(+ SPASE)

    • energy resolution:¶0.07 – 0.10

  •  „cascades“: (e±,  , neutral current)

    • zenith error: 30 - 40°

    • energy resolution:¶ 0.1 – 0.2

    • coverage: 4

¶[log10(E/TeV)]


Atmospheric muons in amanda ii
Atmospheric muons in AMANDA-II

Atmospheric muons and neutrinos: AMANDA‘s test beams

much improved simulation

...but data 30% higher than MC ...

 normalize to most vertical bin

Systematic errors:

10% scattering ( 20m @ 400nm)

absorption (110m @ 400nm)

20% optical module sensitivity

10% refreezing of ice in hole

PRELIMINARY

threshold energy ~ 40 GeV (zenith averaged)


Cosmic ray flux measurement

for QGSJET generator:

(H) = 2.70 ± 0.02

0 (H) = 0.106(7) m-2s-1sr-1TeV-1

Compatible and competitive () with

direct measurements

Cosmic Ray flux measurement

In some cases ice and OM-sensitivity effect can be circumvented ...

(E)=0E-

empirical separation of ice and OM sensitivity effects

PRELIMINARY


Atmospheric n s in amanda ii

spectrum up to 100 TeV

 compatible with Frejus data

presently no sensitivity toLSND/Nunokawa

prediction of dip structures between

0.4-3 TeV

In future, spectrum will be used

to study excess due to cosmic ‘s

Atmospheric n's in AMANDA-II

 neural network energy reconstruction

regularized unfolding

PRELIMINARY

measured atmospheric neutrino spectrum

1 sigma energy error


Search for extraterrestrial neutrinos

- background: neutrinos from cosmic air showers

strong falling energy spectrum,

diffuse in direction

- signal: excess of diffuse flux at high energy,

accumulation at point sources

  • search for muon neutrinos with high energy:

  • upward and

  • downward (with extreme high energy)

  • - search for cascades with high energy

  • - search for point sources


Search for diffuse excess of

extraterrestrial high energy

neutrinos


Search for a tev pev excess in the diffuse flux upward going muons
Search for a TeV-PeV excess in the diffuse flux(upward going muons)

1997 B10-data, accepted by PRL

„AGN“ with 10-5 E-2

GeV-1 cm-2 s-1 sr-1

  • - hit channels as

  • muon energy indicator

  • - cuts determined by MC

  • blind analysis

  • (as all our analyses !)

atm.

Exp.

cut

E2(E) < 8 10-7 GeV-1 cm-2 s-1 sr-1


Search for a pev 100pev excess in the diffuse flux downward muons and muons close to horizon
Search for a PeV-100PeV excess in the diffuse flux(downward muons and muons close to horizon)

EHE events very bright; many PMTs detect multiple photons

vertical

R 10 km

Neural Net Parameter „NN2“ for neutrino vs.atm muon separation

E2(E) <

7.210-7 GeV-1 cm-2 s-1 sr-1

bright MC event near horizon


Synthesis 1 diffuse limit for muon neutrinos
Synthesis 1: Diffuse limit for muon neutrinos

Limits for generic E-2 spectra and specific model shapes:

3·103 – 106 GeV:

E2(E) < 8 10-7

GeV-1 cm-2 s-1 sr-1

2.5·106 – 5.6·108 GeV:

E2(E) < 7.210-7

GeV-1 cm-2 s-1 sr-1

prel.

Expected sensitivity 2000 data:

~ 310-7 GeV-1 cm-2 s-1 sr-1


Diffuse limit from cascades
Diffuse limit from cascades

effective volume

80 TeV – 7 PeV

PRELIMINARY

for E2(E) =10-6GeV cm-2s-1sr-1 expect

9.3 e , 3.8  , 6.2  events

2 candidate events total observed

90% CL limit for

e::=1:1:1

E2all (E) < 9·10 – 7GeV cm-2s-1sr-1


Synthesis 2 flux limits for all flavours
Synthesis 2: flux limits for all flavours

assuming e::=1:1:1

  • multiplicative factor 3

    applied for single  channel

  • special analysis for

    resonant production

    (6.3 PeV)

    90% differential limit

    2.310-20 GeV-1 cm-2 s-1 sr-1

2000  analysis will yield all-flavour limit comparable to cascade limit



Point source search in amanda ii
Point source search in AMANDA II

Search for excess events in sky bins for up-going tracks

- 697 events observed above horizon

- 3% non-neutrino background for  > 5°

- cuts optimized in each declination band

PRELIMINARY

below horizon: mostly atmospheric ‘s

above horizon:mostly fake events

1. Grid Search

(sky subdivided into 300 bins ~7°x7° )

2. Search around defined sources

3. Cluster Search

no clustering observed - no evidence for point sources


upper limits @ 90% CL in units of 10-8cm-2s-1

¶published Ap. J, 582 (2003)

Selected point source flux limits

sensitivity  flat above horizon - 4 times better than B10 ¶!

PRELIMINARY

declination averaged sensitivity:

lim  0.23•10-7 cm-2s-1 @90%


N

Crab

Mark. 501

preliminary 2000 data

GX

339-4

Antares

(2007+)

SS-433

AMANDA + (2007)

-45

0

45

90

-90

1 km3

1 km3 detector, 3 years

Expected source

sensitivity

muons/cm2 s1

AMANDA

137 days

10-14

S

MACRO

8 years

published data

10-15

10-16

10-17

declination (degrees)


Sensitivity for amanda 97 02

SS-433

-45

0

45

90

-90

Mk-501 / ~ 1

sensitivity for AMANDA 97-02

m cm-2 s-1

southern

sky

northern

sky

4 years Super-Kamiokande

10-14

170 days

AMANDA-B10

8 years

MACRO

10-15

declination (degrees)


Is there a signal at higher energies?

no indication of clustering also at higher energies !

increasing energy deposition



Indirect WIMP search

1. Neutrinos from

the Center of Earth

 + 

 b + b

„soft spectrum“

 W + + W -

„hard spectrum“


Rejection of Background

We start with

At this stage the data consist only of up going atmospheric neutrinos and a possible WIMP signal

events at trigger

level in99 data


Effective volume

= # events that pass the cuts

= # events generated in a

volume around the detector


Looking to the center of the earth

Number of events

No statistically significant

excess of vertical muons on top

of the expected atmospheric

neutrino background

NO WIMP SIGNAL HAS BEEN DETECTED !

cosine (muon zenith angle)


upper limits on the muon flux from

neutralino annihilations in the center of the earth

  • Improvement of upper limits from 99-data analysis compared to

  • 97-data analysis

  • is due to

  • the larger 1999

    effective live time

  •  the development

  • of cuts adapted

  • to each WIMP

  • mass individually


Indirect WIMP search

2. Neutrinos from

the Sun

Amanda

At South Pole the Sun sinks maximally 23° below horizon. Therefore

only Amanda-II with ist considerably improved reconstruction for

horizontial tracks (compared to Amanda-B10) can be used for

solar WIMP search.


Upper limits (sensitivities) on the muon flux coming from

neutralino annihilations in the center of the Sun

AMANDA-II results:

• based on 193 days

of live time

• Exclusion sensitivity

from analyzing the

off-source bins

Will un-blind data soon

and look to the Sun.

preliminary

ANTARES and ICECUBE:

MC-calculated

sensitivities


- Search for monopoles

- Supernova monitoring

- Cosmic ray composition


Relativistic Magnetic Monopoles

10-14

Soudan

KGF

Baikal

10-15

MACRO

Cherenkov-Light 

n2·(g/e)2

Orito

upper limit (cm-2 s-1 sr-1)

10-16

Amanda

n = 1.33

(g/e) = 137/ 2

 electrons

10-17

IceCube

10-18

 8300

0.50

0.75

1.00

 = v/c


Count rates

0 5 10 sec

Supernova Monitor

Amanda-II

B10:

60% of Galaxy

A-II:

95% of Galaxy

IceCube:

up to LMC

Amanda-B10

IceCube


Cosmic ray composition studies

iron

AMANDA (correlate to #muons)

proton

log(E/GeV)

SPASE-2 (correlated to #electrons)

robust evidence for composition change around knee ...

cosmic ray composition studies

SPASE-2 (electronic component) - AMANDA B10 (muonic component)

- unique combination!

AMANDA II


blue band: detector and model

uncertainties

red band: uncertainty due to low

energy normalization

confirms trend seen by

other experiments ...

Composition change around „knee“

1015 eV

1016 eV

A=30

A=6

publication in preparation

1998 data


Chem composition
Chem. Composition

Iron

1 km

Proton

AMANDA (number of muons)

log(E/PeV)

2 km

Spase (number of electrons)

Chemical Composition

preliminary


Outlook
Outlook

(still to be done)


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