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

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 Berkeley ≈ 150 members ≈ ≈ ≈ UC Irvine Pennsylvania State UW Madison UW River Falls LBNL Berkeley U. Simón Bolivar, Caracas + University of Maryland, US VUB-IIHE, Brussel Clark-Atlanta University, US ULB-IIHE, Bruxelles Southern University, US IAS, Princeton, US Université de Mons-Hainaut University of Alabama, US Imperial College, London University of Oxford, UK DESY, Zeuthen University of Utrecht, NL Mainz Universität Chiba University, Japan Wuppertal Universität U. of Canterbury, Christchurch, NZ Stockholm Universitet Uppsala Universitet as ICECUBE members Kalmar Universitet South Pole Station

NEUTRINO ASTRONOMY NEUTRINO ASTRONOMY • Cosmic rays @ >>TeV exist � acceleration sites must sit somewhere explained explained by SN by SN } • SNe remnants ? • Active Galactic Nuclei proton accelerators • Gamma Ray Bursts • Exotics (decays of topological defects...) unexplained unexplained Guaranteed sources: • atmospheric neutrinos (from π π & K mesons decay) π π � Neutrinos : not absorbed, not deflected: • galactic plane: � difficult to detect – CR interacting with ISM, concentrated on the disk � Protons : deflected in magnetic fields, GZK • CMB (diffuse): � γ -rays : propagate straight, however: γ γ γ ∆ + � n π π + (p π – reprocessed in sources π 0 ) – UHE p γ � ∆ γ γ γ γ � γ ∆ ∆ π π π π γ γ – absorbed in IR (100 TeV) and 3K (10 PeV)

THE AMANDA DETECTOR THE AMANDA DETECTOR O(km) long muon tracks determination of the trajectory by Cherenkov light timing ≈ 12 m 19 strings ≈ ≈ ≈ 0 . 5 − 1 . 5 ( E / TeV ) 677 PMTs Θ ≈ ° ⋅ µν ν trigger rate: 80 Hz PMT noise rate: 1 kHz • need up/down rejection ≈ 10 -6 ⇒ background from atmospheric muons

ALL FLAVOUR DETECTION ALL FLAVOUR DETECTION Electromagnetic and hadronic cascades • ν τ : oscillation + regeneration at PeV ν ν ν τ τ τ � important • no EM / hadronic cascade differentiation (even if slightly different shape and lower light output for hadronic cascades) ~ 5 m

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

THE SITE THE SITE geographic South Pole AMANDA 2km deep

DETECTOR MEDIUM: ICE PROPERTIES DETECTOR MEDIUM: ICE PROPERTIES in-situ light sources ice optical parameters : atmospheric muons λ abs ~ 110 m @ 400 nm λ scatt ~ 20 m @ 400 nm

DETECTOR CAPABILITIES DETECTOR CAPABILITIES ν µ effective area muons: (schematic): directional error: 1.5 ° - 2.5 ° σ ( log( ∆ E/E ) ) : 0.3 – 0.4 ν -interaction in earth, coverage: 2 π ν ν ν π π π detector response showers: (e ± , τ ± , neutral current) zenith error: 30 ° - 40 ° 5m 2 σ ( log( ∆ E/E ) ) : 0.1 – 0.2 (5TeV < E < 5 PeV) coverage: 4 π π π π ∝ E ν 2 primary cosmic rays: (+ SPASE2) energy resolution: 0.07 – 0.10 3 cm 2 100 GeV 100 TeV 100 PeV

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

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)

TeV- -PeV PeV DIFFUSE FLUX DIFFUSE FLUX TeV • data sample ’97: 10 9 evts data 2000 analysis on the way 10 -5 E -2 GeV -1 cm -2 s -1 sr -1 • hit channel multiplicity as energy indicator atm. ν • cuts optimized for best Exp. sensitivity cut • Above optimal cut N ch >54: N obs = 3 evts ν = 3.06 ± 25% norm ± ~35% sys N atm ν ν ν NO EXCESS OBSERVED PRL 90 (2003), 251101 assuming a E -2 flux (6 TeV < E ν < 1 PeV ) : E 2 Φ νµ (E) < 8.4 ⋅ 10 -7 GeV cm -2 s -1 sr -1

TeV- -PeV PeV DIFFUSE FLUX: LIMITS DIFFUSE FLUX: LIMITS TeV Comparison to other experimental E -2 limits Limits for other flux predictions: N ch 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) Stecker et al, Phys Rev Lett 66 1991, 69 1992 Szabo-Protehoe 92 X X Stecker, Salamon. Space Sc. Rev. 75, 1996 Protehoe. ASP Conf series, 121, 1997 X

HE DIFFUSE FLUX (cascades cascades) ) HE DIFFUSE FLUX ( • 2000 data sample, 197 days lifetime. 1.2x10 9 events @ trigger level • After optimized cuts : • sim. BG: N obs = 1 evts atm. muons (920 d) N atm µ µ = 0.90 +0.69 atm. neutrinos –0.43 µ µ N atm ν ν = 0.06 +0.09 -0.04 ± 25% norm ν ν no earth propagation effects ν ν ν ν τ τ τ τ ν µ ν ν ν µ µ µ ν e ν ν ν

HE DIFFUSE FLUX (cascades cascades): LIMITS ): LIMITS HE DIFFUSE FLUX ( • sensitivity to all three flavors • assuming a E -2 flux: ν (E) < 0.86·10 – 6 GeV cm -2 s -1 sr -1 E 2 Φ Φ Φ Φ all ν ν ν ν e : ν µ : ν τ =1:1:1 ) ( ν ν µ ν τ ν ν ν ν ν ν µ µ τ τ paper submitted to Phys. Rev. D • for specific models: some AGN core-production models discarded @ 90% CL (dashed in figure) From data sample ’97, 130 days lifetime ( 5 TeV < E ν < 300 TeV ): E 2 Φ ν (E) < 9.8·10 – 6 GeV cm -2 s -1 sr -1 Φ all ν Φ Φ ν ν ν e : ν µ : ν τ =1:1:1 ) ( ν ν ν ν µ ν ν ν ν ν τ µ µ τ τ E 2 Φ ν e (E) < 6.5·10 – 6 GeV cm -2 s -1 sr -1 Φ Φ Φ ν ν ν Phys. Rev. D67, 2003

UHE neutrinos neutrinos UHE ν Simulated µ UHE event E ν > 10 16 eV: Earth opaque Search in the upper hemisphere Experiment and close to horizon CORSIKA MC Increased ν -Xsection (but uncertainties at these energies) Long µ tracks (> 10 Km) 10 -6 E -2 Bright events low atm µ background Energy -related variables best handle of analysis Neural Net parameter for neutrino vs. atm muon separation

UHE neutrinos neutrinos: Limits : Limits UHE PRELIMINARY Data sample: 1997. 131 d livetime Average all angles N obs = 5 evts Horizontal events N bck = 4.6 ± 36% evts ν effective area vs log E ν ν ν ν ν ν ν assuming a E -2 flux ( 1 PeV < E ν < 3 EeV ) : ⋅ 10 -6 GeV cm -2 s -1 sr -1 E 2 Φ NO EXCESS ν (E) < 1.5 ⋅ Φ all ν Φ Φ ⋅ ⋅ ν ν OBSERVED ν e : ν µ : ν τ =1:1:1 ) ( ν ν µ ν τ ν ν ν ν ν ν µ µ τ τ paper in progress

POINT SOURCE SEARCHES POINT SOURCE SEARCHES Search for an event excess in the northern sky � grid: sky subdivided into 300 bins ~7°x7° (zenith dependent) between 0 o < δ < 85 o •cuts optimized in each declination band Eff. area vs µ µ energy (2000 data) µ µ P R E X 10 -7 GeV -1 cm -2 L I M •sensitivity ≈ flat up to horizon, I Sensitivity 2 independent N A R analyses in 2000 Y s -1 ( in average 4 times better than 1997 analysis , Astrophys. J. 583, 2003 ) zenith X1.8 improvement by combining 2 yrs of data. Work in progress

POINT SURCE SEARCHES: FLUX LIMITS POINT SURCE SEARCHES: FLUX LIMITS below horizon: mostly atmospheric ν ν ‘s ν ν (this means northern sky) 2000 data: upper limits in units of 10 -7 cm -2 s -1 above horizon:atm µ µ events µ µ ν >10 GeV, assumed E -2 spectral shape E ν ν ν 699 neutrino events observed from below the declination averaged sensitivity horizon (2000 data) (integrated above 10 GeV) : <10% non-neutrino background for θ >5° lim ≈ ≈ 2.3·10 -8 cm -2 s -1 Φ Φ Φ Φ ν ≈ ≈ no clustering observed: ν ν ν no evidence for point sources Phys. Rev. Lett. 92, 071102,2004

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