RESULTS FROM AMANDA AMANDA Carlos de los Heros Division of High - - PowerPoint PPT Presentation

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RESULTS FROM AMANDA AMANDA Carlos de los Heros Division of High - - PowerPoint PPT Presentation

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RESULTS FROM AMANDA AMANDA Carlos de los Heros Division of High Energy Physics Uppsala University CRIS04 Catania, Italy, May 31-June 4 The AMANDA/ICECUBE AMANDA/ICECUBE Collaborations Collaborations The Bartol Research Institute UC

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SLIDE 1

Carlos de los Heros

Division of High Energy Physics Uppsala University CRIS04 Catania, Italy, May 31-June 4

RESULTS FROM AMANDA AMANDA

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SLIDE 2

The The AMANDA/ICECUBE AMANDA/ICECUBE Collaborations Collaborations

Bartol Research Institute UC Berkeley UC Irvine Pennsylvania State UW Madison UW River Falls LBNL Berkeley

  • U. Simón Bolivar, Caracas

VUB-IIHE, Brussel ULB-IIHE, Bruxelles Université de Mons-Hainaut Imperial College, London DESY, Zeuthen Mainz Universität Wuppertal Universität Stockholm Universitet Uppsala Universitet Kalmar Universitet South Pole Station

+ University of Maryland, US

Clark-Atlanta University, US Southern University, US IAS, Princeton, US University of Alabama, US University of Oxford, UK University of Utrecht, NL Chiba University, Japan

  • U. of Canterbury, Christchurch, NZ

as ICECUBE members

≈ ≈ ≈ ≈150 members

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SLIDE 3

NEUTRINO ASTRONOMY NEUTRINO ASTRONOMY

  • Cosmic rays @ >>TeV exist

acceleration sites must sit somewhere

  • SNe remnants
  • Active Galactic Nuclei
  • Gamma Ray Bursts
  • Exotics (decays of topological defects...)

}

proton accelerators

  • Neutrinos : not absorbed, not deflected:

difficult to detect

  • Protons : deflected in magnetic fields, GZK
  • γ

γ γ γ-rays : propagate straight, however:

– reprocessed in sources – absorbed in IR (100 TeV) and 3K (10 PeV)

?

explained explained by SN by SN unexplained unexplained

Guaranteed sources:

  • atmospheric neutrinos (from π

π π π & K mesons decay)

  • galactic plane:

– CR interacting with ISM, concentrated on the disk

  • CMB (diffuse):

– UHE p γ

γ γ γ γ γ γ γ

∆

∆ ∆ ∆+ n π π π π+ (p π π π π0)

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SLIDE 4

THE AMANDA DETECTOR THE AMANDA DETECTOR

19 strings 677 PMTs

trigger rate: 80 Hz PMT noise rate: 1 kHz O(km) long muon tracks ≈ ≈ ≈ ≈ 12 m

5 .

) TeV / ( 5 . 1

−

⋅ ° ≈ Θ

ν µν

E

  • need up/down rejection ≈ 10-6

⇒ background from atmospheric muons

determination of the trajectory by Cherenkov light timing

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SLIDE 5

Electromagnetic and hadronic cascades

~ 5 m

  • ν

ν ν ντ

τ τ τ : oscillation + regeneration at PeV

important

  • no EM / hadronic cascade differentiation

(even if slightly different shape and lower light output for hadronic cascades)

ALL FLAVOUR DETECTION ALL FLAVOUR DETECTION

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SLIDE 6

TWR UPGRADE TWR UPGRADE

  • Transient Waveform Recorder system

installed between the 2001 and 2004 campaigns

  • Increased OM dynamic range x ~100
  • Increased 1pe detection efficiency
  • Virtually dead-time free
  • Manageable trigger rate: ~150 Hz

(majority 18)

  • Possibility of using software trigger

Physics benefits:

  • Improved angular resolution
  • Improved energy resolution

UHE/EHE physics

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SLIDE 7

geographic South Pole

AMANDA

THE SITE THE SITE

2km deep

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SLIDE 8

in-situ light sources atmospheric muons

DETECTOR MEDIUM: ICE PROPERTIES DETECTOR MEDIUM: ICE PROPERTIES

ice optical parameters: λabs ~ 110 m @ 400 nm λscatt ~ 20 m @ 400 nm

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SLIDE 9

DETECTOR CAPABILITIES DETECTOR CAPABILITIES

muons: directional error: 1.5° - 2.5° σ(log(∆E/E)): 0.3 – 0.4 coverage: 2π π π π showers: (e±, τ± , neutral current) zenith error: 30° - 40° σ(log(∆E/E)) : 0.1 – 0.2

(5TeV < E < 5 PeV)

coverage: 4π π π π primary cosmic rays: (+ SPASE2) energy resolution: 0.07 – 0.10

3 cm2 5m2

νµ effective area (schematic): ∝ Eν

2

ν ν ν ν-interaction in earth, detector response

100 GeV 100 TeV 100 PeV

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SLIDE 10

AMANDA can operate in very different energy regimes

Energy range analysis production site(s)

~MeV SN ν Supernovae GeV - ~TeV atm ν atmosphere Dark matter Sun/Earth TeV - PeV diffuse AGN, GRB… cascades point sources PeV – EeV UHE AGN, TD… > EeV EHE ? Agreed collaboration strategy: Analyses are done ‘blind’. cuts optimized on a % of data or on a time-scrambled data set.

(except for SN searches where analysis is based on detector noise rate

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SLIDE 11

AMANDA PHYSICS TOPICS AMANDA PHYSICS TOPICS

Cosmology / Particle Physics / Astrophysics

  • primary CR spectrum:

atmospheric neutrinos (also calibration/background of Amanda) CR composition (with surface detector SPASE-2)

  • CR origin (acceleration sites: AGN, GRBs)

extra-terrestrial flux (diffuse / punctual / transient) @ >TeV energies

  • Dark matter / exotic particles: neutralinos, magnetic monopoles, extra dim.

WIMP’s signature: Excess from the Sun/Earth’s center direction heavy and slow particles

Topological defects: extra-terrestrial UHE diffuse flux

  • SN monitor of the Milky Way

low energy EM cascades (global noise increase throughout AMANDA)

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SLIDE 12

TeV TeV-

  • PeV

PeV DIFFUSE FLUX DIFFUSE FLUX

  • data sample ’97: 109 evts

data 2000 analysis on the way

  • hit channel multiplicity as

energy indicator

  • cuts optimized for best

sensitivity

  • Above optimal cut Nch>54:

Nobs = 3 evts Natm ν

ν ν ν = 3.06 ± 25%norm± ~35% sys

atm.ν Exp.

10-5 E-2 GeV-1 cm-2 s-1sr-1

cut

E2 Φνµ(E) < 8.4 ⋅10-7 GeV cm-2 s-1 sr-1

PRL 90 (2003), 251101

NO EXCESS OBSERVED

assuming a E-2 flux (6 TeV < Eν < 1 PeV) :

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SLIDE 13

TeV TeV-

  • PeV

PeV DIFFUSE FLUX: LIMITS DIFFUSE FLUX: LIMITS

Comparison to other experimental E-2 limits Limits for other flux predictions: Nch cut optimized for each case. Expected limit from a given model compared with observed limit. Some AGN models excluded at 90% CL (marked as X below)

Szabo-Protehoe 92 Stecker et al, Phys Rev Lett 66 1991, 69 1992 Stecker, Salamon. Space Sc. Rev. 75, 1996

  • Protehoe. ASP Conf series, 121, 1997

X X X

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SLIDE 14

HE DIFFUSE FLUX ( HE DIFFUSE FLUX (cascades cascades) )

no earth propagation effects

ν ν ν νµ

µ µ µ

ν ν ν ντ

τ τ τ

ν ν ν νe

  • 2000 data sample, 197 days lifetime.

1.2x109 events @ trigger level

  • sim. BG:
  • atm. muons (920 d)
  • atm. neutrinos
  • After optimized cuts :

Nobs = 1 evts Natm µ

µ µ µ = 0.90 +0.69 –0.43

Natm ν

ν ν ν = 0.06+0.09

  • 0.04± 25%norm
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SLIDE 15

HE DIFFUSE FLUX ( HE DIFFUSE FLUX (cascades cascades): LIMITS ): LIMITS

  • sensitivity to all three

flavors

  • assuming a E-2 flux:
  • for specific models:

some AGN core-production models discarded @ 90% CL

(dashed in figure)

E2Φ Φ Φ Φall ν

ν ν ν(E) < 0.86·10 – 6 GeV cm-2 s-1 sr-1

( ν

ν ν νe:ν ν ν νµ

µ µ µ:ν

ν ν ντ

τ τ τ =1:1:1)

paper submitted to Phys. Rev. D

E2Φ Φ Φ Φall ν

ν ν ν(E) < 9.8·10– 6 GeV cm-2 s-1 sr-1

( ν

ν ν νe:ν ν ν νµ

µ µ µ:ν

ν ν ντ

τ τ τ =1:1:1)

E2Φ Φ Φ Φν

ν ν νe(E) < 6.5·10– 6 GeV cm-2 s-1 sr-1

  • Phys. Rev. D67, 2003

From data sample ’97, 130 days lifetime (5 TeV < Eν < 300 TeV):

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SLIDE 16

UHE UHE neutrinos neutrinos

µ ν

Simulated UHE event

Eν > 1016 eV: Earth opaque Search in the upper hemisphere and close to horizon Increased ν-Xsection (but uncertainties at these energies) Long µ tracks (> 10 Km) Bright events low atm µ background

Energy -related variables best handle of analysis

10-6 E-2

Neural Net parameter for neutrino

  • vs. atm muon separation

Experiment CORSIKA MC

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SLIDE 17

UHE UHE neutrinos neutrinos: Limits : Limits

NO EXCESS OBSERVED

E2 Φ Φ Φ Φall ν

ν ν ν(E) < 1.5⋅

⋅ ⋅ ⋅10-6 GeV cm-2 s-1 sr-1

( ν

ν ν νe:ν ν ν νµ

µ µ µ:ν

ν ν ντ

τ τ τ =1:1:1)

assuming a E-2 flux (1 PeV < Eν < 3 EeV) :

paper in progress

PRELIMINARY Nobs = 5 evts Nbck = 4.6 ± 36% evts

Data sample: 1997. 131 d livetime

Average all angles

ν ν ν ν effective area vs log Eν ν ν ν

Horizontal events

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SLIDE 18

POINT SOURCE SEARCHES POINT SOURCE SEARCHES

  • cuts optimized in each declination band
  • sensitivity ≈ flat up to horizon,

(in average 4 times better than 1997 analysis, Search for an event excess in the northern sky grid: sky subdivided into 300 bins ~7°x7°

(zenith dependent) between 0o < δ < 85o

  • Astrophys. J. 583, 2003 )

zenith Sensitivity

X 10-7 GeV-1 cm-2 s-1 2 independent analyses in 2000

P R E L I M I N A R Y

X1.8 improvement by combining 2 yrs

  • f data. Work in progress
  • Eff. area vs µ

µ µ µ energy (2000 data)

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SLIDE 19

POINT SURCE SEARCHES: FLUX LIMITS POINT SURCE SEARCHES: FLUX LIMITS

below horizon: mostly atmospheric ν ν ν ν‘s

(this means northern sky)

above horizon:atm µ µ µ µ events

2000 data: upper limits in units of 10-7cm-2s-1 Eν

ν ν ν>10 GeV, assumed E-2 spectral shape

699 neutrino events observed from below the horizon (2000 data) <10% non-neutrino background for θ>5°

no clustering observed: no evidence for point sources

declination averaged sensitivity

(integrated above 10 GeV) :

Φ Φ Φ Φν

ν ν ν lim ≈

≈ ≈ ≈ 2.3·10-8 cm-2s-1

  • Phys. Rev. Lett. 92, 071102,2004
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SLIDE 20

POINT SURCE SEARCHES: FLUX LIMITS POINT SURCE SEARCHES: FLUX LIMITS

Upper limits in units of 10-8cm-2s-1 for an assumed E-2 neutrino spectral shape integrated above Eν=10 GeV on some selected sources:

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SLIDE 21

SEARCH FOR SEARCH FOR ν νµ

µ CORRELATED WITH

CORRELATED WITH GRBs GRBs

  • Catalogs:

BATSE, IPN3

  • Analysis is blind: finalized off-source

(±5 min) with MC signal

  • ∆Ψ

∆Ψ ∆Ψ ∆Ψ<20° + other event quality parameters

  • BG stability required within ±1 hour

from burst

  • µ

µ µ µ effective area ≈ 50000 m2

Low background analysis due to both space and time coincidence!

10 min 1.88 0.60 46 (New) A-II 2000 1.47 1.24 114 (All) A-II 2000 97-00 2000 2000 1999 1998 1997 Year 1.45 1.29 312 (BT) B-10/A-II A-II A-II

(2 analyses)

B-10 B-10 B-10 Detector 2.19 0.24 24 (BNT) 1.72/2.05 0/0 0.83/0.40 44 (BT) 2.24 0.20 96 (BT) 2.24 0.20 94 (BT) 2.41 0.06 78 (BT) Event U.L. NObs NBG, Pred NBursts

(BT = BATSE Triggered BNT = BATSE Non-Triggered New = IPN & GUSBAD)

97-00 Flux Limit at Earth: E2Φν≤

≤ ≤ ≤ 4x10-8 GeV cm-2 s-1 sr-1

For 312 bursts w/ Broken Power-Law Spectrum (Ebreak=100 TeV, Γ=300)

PRELIMINARY

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SLIDE 22

SPASE/AMANDA: CR composition

SPASE (scintillator array @ 3000m, ~685 g cm-2) e density @ surface shower core resolution: 0(m) shower direction resolution: < 1.5o AMANDA µ µ µ µ‘s @ >1500m (>300 GeV @ surface) use SPASE core position for combined fit use expected lateral photoelectron/event distribution as estimate of Nµ

µ µ µ

369m AMANDA 1500m

SPASE-2 (number of electrons) AMANDA (number of muons)

l

  • g

( E / P e V ) ln(A)

Proton Iron

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SLIDE 23

SPASE/AMANDA: CR SPASE/AMANDA: CR composition composition (

(cont cont.) .)

Amanda-B10 / Spase-2 CR composition: paper accepted in Astropart. Phys.

Combined SPASE-AMANDA ‘detector’: Probes hadronic (µ µ µ µ) and EM (e) energy in the primary shower

σ σ σ σ(E) ~ 0.07 in log(Eprim)

Results compatible with composition change around the knee Sources of systematic uncertainties:

(~30% in ln(A), not shown in the plot)

  • shower generation models
  • muon propagation
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SLIDE 24

OUTLOOK OUTLOOK

  • First results from AMANDA-II published (2000 data)
  • Amanda-II detector shows greatly improved capabilities

Sensitivity at the level of current predictions of ν ν ν ν production in AGN. Some models excluded @ 90CL

  • combined analysis ’00-’03 on its way
  • papers from analysis of 97-2000+ data in progress
  • digitized readout since 2003: waveform resolution
  • ice description mature: being fully implemented in MC
  • first IceCube strings in 2004/05 antarctic season