1. Frontiers in Contemporary Physics: May 23, 2005 Recent Results From AMANDA and IceCube Jessica Hodges University of Wisconsin – Madison for the IceCube Collaboration

2. Why study neutrinos? Protons: easily detected, but deflected by magnetic fields. Direction of cosmic ray origin is unknown. Photons: absorbed by matter and will interact with the microwave and IR backgrounds. Carry directional information. Neutrinos: not deflected by magnetic fields, therefore they keep their directional information. Low cross-section means they rarely interact and are hard to detect. p  AMANDA IceCube

3. Neutrino Production Cosmic accelerators that are suspected to produce high energy cosmic rays include: Gamma Ray Bursts (GRBs) Active Galactic Nuclei (AGNs) Supernova Remnants ? Due to Fermi acceleration, neutrinos are predicted to arrive with an E -2 energy spectrum Bottom-Up scenario p + (p or  )    + X  e,  + X e :  :  = 1 : 2 : 0 at source e :  :  = 1 : 1 : 1 at Earth (due to oscillations)

4. Amundsen-Scott South Pole Station South Pole Dome Summer camp AMANDA road to work 1500 m 2000 m [not to scale] Where are we ?

5. Université de Mons-Hainaut, Mons, Belgium University Gent, Gent, Belgium University of Alabama, Tuscaloosa, AL University of California-Berkeley, Berkeley, CA, USA University of California-Irvine, Irvine, CA, USA University of Canterbury, Christchurch, New Zealand University of Delaware, Newark, DE, USA University of Kansas, Lawrence, KS, USA University of Maryland, College Park, MD, USA University of Oxford, Oxford, UK University of Wisconsin-Madison, Madison, WI, USA University of Wisconsin-River Falls, River Falls, WI, USA Uppsala Universitet, Uppsala, Sweden Utrecht University, Utrecht, Netherlands Vrije Universiteit Brussel, Brussels, Belgium Chiba University, Chiba, Japan CTSPS, Clark Atlanta University, Atlanta, GA, USA DESY, Zeuthen, Germany Humboldt Universität, Berlin, Germany Imperial College, London, UK Institute for Advanced Study, Princeton, NJ, USA Lawrence Berkeley National Laboratory, Berkeley, CA, USA Pennsylvania State University, University Park, PA, USA Amundsen-Scott Station, Antarctica Southern University and A & M College, Baton Rouge, LA, USA Stockholm Universitet, Stockholm, Sweden Universität Dortmund, Dortmund, Germany Universität Mainz, Mainz, Germany Universität Wuppertal, Wuppertal, Germany Université Libre, Brussels, Belgium IceCube Collaboration

6. Antarctic Muon and Neutrino Detector Array AMANDA-B10 inner 10 strings 302 Optical Modules Operating from 1997-1999 AMANDA-II 19 strings 677 Optical Modules Operating from 2000-now Trigger Rate~80 Hz PMT noise ~ 1kHz sdfgsdfg Optical Module: Down-looking photomultiplier tube enclosed in a pressure resistant glass sphere Ice Properties: dust layers exist at different depths for wavelength = 400 nm, average absorption length = 110 m average effective scattering length = 20 m

7. Neutrino Induced Events in the Ice “Up-going” (from Northern sky) “Down-going” (from Southern sky) ν μ charged current interactions produce Cherenkov light along long tracks. Pointing resolution ~ 2 o Energy resolution ~ 0.3 - 0.4 in log 10 (E / TeV) Coverage: 2  ν e and ν τ charged current interactions and all flavor neutral current interactions induce cascades in the ice. Pointing resolution ~ 30 o Energy resolution ~ 0.1 – 0.2 in log 10 (E / TeV) Coverage: 4  Muon Track Cascade ~15 m

8. Diffuse Neutrino Analysis (TeV – PeV)    “Signal” downgoing muons and neutrinos E -3.7 E -2 Number of Optical Modules hit (scales with the neutrino energy) Reconstructed Muon Event: To select high quality upgoing events, apply cuts to the data based on the observables of the event. Separate atmospheric and E -2 signal neutrinos with an energy cut. Monte Carlo based sensitivity optimization using the Feldman – Cousins prescription Diffuse flux = flux from unresolved neutrino sources Arbitrary units

9. Another Method of Setting a Diffuse ν μ Limit log of the neutrino energy (GeV) Reconstruct the atmospheric neutrino spectrum and use this to set a diffuse limit Neural Network Energy Reconstruction Regularized unfolding gives the energy spectrum Setting a limit on the diffuse flux of E-2 cosmic neutrinos: This limit corresponds to the highest allowed E -2 cosmic neutrino signal within the the uncertainty of the highest energy bin. Limit on Diffuse E -2 ν μ flux:  E 2 (E) < 2.6 x 10 -7 GeV cm -2 s -1 sr -1 Range: 100 – 300 TeV Data Year: 2000 * Preliminary *

10. Preliminary Muon Neutrino Flux Limits

11. Cascade Diffuse Neutrino Analysis N obs = 1 event N atm  = 0.90 N atm ν = 0.06 ± 25% norm Astroparticle Physics 22 (2004) 127 Sensitive to all three neutrino flavors +0.69 -0.43 +0.09 -0.04 All flavor limit on diffuse E -2 neutrino flux:  E 2 (E) < 8.6 x 10 -7 GeV cm -2 s -1 sr -1 Range: 50 TeV – 5 PeV Data Year: 2000 Cuts optimized on topology and energy

12. PeV – EeV Diffuse Neutrino Analysis Ultra high energy neutrinos have large cross-sections --> PeV and EeV neutrinos that enter the earth in the Northern Hemisphere are likely to interact before reaching AMANDA Best detection strategy: Look near the horizon and just above it. True cosmic neutrino events should be very bright (large number of hits in the detector). Using a neural net trained to distinguish ultra high energy cosmic E -2 events from background: Limit on Diffuse E -2 neutrino flux:  all E 2 (E) < 0.99 x 10 -6 GeV cm -2 s -1 sr -1 Range: 1 PeV – 3 EeV Data Year: 1997

13. Neutrino Point Source Search 2000 – 2003 Sky Map 807 days of livetime 3329 upgoing events (3438 atmospheric events expected) All events shown are consistent with the atmospheric neutrino background. No extraterrestrial E -2 signal observed. Two Search Methods: 1) Look for clusters of events around a predefined list of neutrino source candidates. 2) Grid search : Shift the grid repeatedly to look for a clustering of events. This allows you to find sources not on the predefined list.

14. Neutrinos from Gamma Ray Bursts Background determined on-source / off-time Blinded Window -1 hour+1 hour 10 min Time of GRB (start of T 90 ) 97-00 Flux Limit at Earth*: E 2 Φ ν ≤ 4·10 -8 GeV cm -2 s -1 sr -1 00-03 Flux Limit at Earth*: E 2 Φ ν ≤ 3·10 -8 GeV cm -2 s -1 sr -1 Using space and time coincidence leads to a very low background. Separate analyses are currently underway using both the average Waxman-Bahcall parameters and burst-specific observables. YearDetectorBursts Background Predicted Number Observed Event Upper Limit 1997-2000B-10 / A-II 312 (BATSE) 1.2901.45 2000-2003A-II 139 (BATSE + IPN) 1.2501.47 * Preliminary *

15. Indirect Dark Matter Search for Neutralinos Gravitationally Trapped in the Sun Limits on muon flux from the Sun COLOR CODE: Disfavored by CDMS II Will be ruled out when experiments reach 10x current sensitivity Require greater than 10x current sensitivity to probe

16. detection radius SuperNova Early Warning System SNEWS is a collaborative effort between Super-K, SNO, LVD, KamLAND, AMANDA, BooNE and several gravitational wave experiments Bursts of low-energy (MeV) neutrinos from core collapse supernovae AMANDA detection: - simultaneous increase of all PMT count rates (~10 s) - can detect 90% of SN within 9.4 kpc - less than 15 fakes per year AMANDA-II AMANDA-B10 IceCube 30 kpc AMANDA-B10 sees 70% of the galaxy AMANDA-II sees 90% of the galaxy IceCube will see out to the LMC

17. IceCube: The Future one cubic kilometer 80 strings with 60 Digital Optical Modules per string Optimized for detection of TeV – PeV neutrinos 17 m vertical spacing of DOMs 125 m between strings 2 IceTop Tanks with 2 Digital Optical Modules above each IceCube string Estimated completion: 2010 1450 m 2450 m 300 m AMANDA

18. ~300m for 10 PeV  Event Simulation in IceCube Very high energy events that saturate AMANDA will be clearly distinguished in IceCube.  muon event e cascade event  double bang event E = 10 TeV E = 375 TeV

19. Recent Deployment January 27, 2005 First IceCube String Deployed! 60 Digital Optical Modules are in the ice 8 IceTop tanks deployed IceCube Drill Camp

20. Limits have been set and multi-year AMANDA analyses are getting closer to the Waxman-Bahcall diffuse neutrino upper limit. However, no extraterrestrial neutrino signal has been observed yet. AMANDA is successful as a proof-of-concept and is the largest neutrino detector in the world. IceCube is under construction. One IceCube string has been deployed and all DOMs are communicating successfully. www.icecube.wisc.edu hodges@icecube.wisc.edu Conclusions IceTop Spring 2005 data event: Run 872 Event 5945 First IceCube string