IceCube: Physics, status and future

Transcription

1 IceCube Physics, status and future Klas Hultqvist International Workshop on Very Large Volume neutrino Telescopes Athens October 2009

2 Introduction Analysis and results Future

3 The IceCube Collaboration Univ Alabama, Tuscaloosa Uppsala universitet Univ Alaska, Anchorage Stockholms universitet UC Berkeley Oxford University Universität Mainz UC Irvine Humboldt Univ., Berlin Clark-Atlanta University DESY, Zeuthen U Delaware / Bartol Research Inst Chiba University Universität Dortmund Georgia Tech Universität Wuppertal University of Kansas MPI Heidelberg Lawrence Berkeley National Lab RWTH Aachen University of Maryland Bonn Ohio State University Bochum Pennsylvania State University University of Wisconsin-Madison University of Wisconsin-River Falls Université Libre de Southern University, Baton Rouge Bruxelles Vrije Universiteit Brussel Université de Mons-Hainaut Universiteit Gent University of Canterbury EPFL, Lausanne 34 Institutes

4 IceCube deployment IceCube lab 50m Currently (IC59) 2010/11 59 strings, each with 60 Optical modules in the ice 2 IceTop tanks with 2 DOMs each 1450m 2009/10 Ready! ( ) Amanda In 2011 (IC86) 86 strings, including Deep Core low energy 2450m addition 2820m 59/86=68% Bedrock

5 Neutrino transmission through the Earth C.Spiering Look down (north) for TeV to avoid large CR muon background (traditionally...)

6 IceCube DOM (Digital Optical Module) 10' Hamamtsu PMT Low noise (~300Hz) from 40K in glass ATWD 300 MHz sampling for 400 ns fadc 40 MHz for 6.4 s

7 Drilling and deployment Drill/deployment towers Water heating (5 MW) IceTop tanks hose reel

8 IceTop air shower array Two DOMs (high and low gain) per tank Two tanks per string (station) Diffusively reflective liner

9 A muon track in IC40 Good direction determination for CC interactions Not so good for e or NC events (cascades) and air showers example (simulation, 47 PeV)

10 Pointing accuracy Reconstructed zenith distribution for muon tracks passing quality cuts. IC22 P.Berghaus et al. (ISVECRI 08) J.Dumm et al. (ICRC09) PSF for for different geometries (and software)

11 Moon shadow with cosmic ray muons 0.5 primary CRs Zenith distance from Moon ( ) Boersma, Gladstone, Karle (ICRC09) Azimuth distance from Moon ( ) A 5 shadow is seen in the bin around the Moon. No evident directional bias. Statistics will increase.

12 Anisotropy of cosmic rays, IC22 First time for Southern Hemisphere. High statistics using nano DST data. R.Abbasi et al. (ICRC09) ~13 TeV evts Modulation= ~130 TeV evts Modulation= Compare with Northern Hemisphere TIBET MILAGRO

13 A big event! A CR shower of ~ ev seen in IceTop and deep ice

14 The Ice AMANDA measurements J.Geophys.Res. 111,D13203,2006 Reflected light signal IceCube dust logger The ice model and its representation in software are constantly checked against data from CR muons and special devices. Further improvements are desirable. (And expected!)

15 Muon energy reconstruction From counting individual photons in DOM waveforms the muon energy can be determined within a factor ~2 with IC22 (± 0.3 in log10 E). Work in progress! Systematic effects not fully understood. D.Chirkin et al (ICRC09).

16 Analysis and results Notes 1. There is much more going on than I can cover! 2. The detector will be completed in 2011 and is expected to take data for years. Current results are based on a very small fraction of the data expected. IC IC IC (no results yet)

17 The Physics (Contributions to ICRC'09 in boxes) 1. Point sources All sky search or pre defined sources in space and (sometimes) time (AGNs, microquasars, non uniform source populations). Search for High Energetic Neutrinos from Supernova Explosions with AMANDA AMANDA 7 Year Multipole Analysis Moon Shadow Observation by IceCube Likelihood Point Source Search with IceCube IceCube Time Dependent Point Source Analysis Using Multiwavelength Information Search for neutrino flares from point sources with IceCube Neutrino triggered high energy gamma ray follow up with IceCube IceCube/AMANDA combined analyses for the search of neutrino sources at low energies 2. Diffuse flux/atmospheric neutrinos Measure energy spectrum and look for deviations from expectation for atmospheric neutrinos (extraterrestrial s, neutrino oscillations, quantum gravity...) Search for Diffuse High Energy Neutrinos with IceCube First search for extraterrestrial neutrino induced cascades with IceCube Direct Atmospheric Muon Energy Spectrum Measurement with IceCube Atmospheric Neutrino Oscillation Measurements with IceCube Search for Ultra High Energy Neutrinos with AMANDA Improved Reconstruction of Cascade like Events in IceCube Measurement of the atmospheric neutrino energy spectrum with IceCube A new method for identifying neutrino events in IceCube data A Search For Atmospheric Neutrino Induced Cascades with IceCube Search for Quantum Gravity with IceCube and High Energy Atmospheric Neutrinos

18 The Physics (cont'd) 3. Cosmic Rays (using IceTop and deep ice detector) Composition, energy spectrum, directionality, local variations (solar and atmospheric) Small air showers in IceCube Reconstruction of IceCube coincident events and study of composition sensitive observables using both the surface and deep detector Composition in the knee region with SPASE AMANDA A First All Particle Cosmic Ray Energy Spectrum From IceTop Atmospheric Variations as observed by IceCube Study of High p_t Muons in IceCube Large scale Cosmic Rays Anisotropy as Observed With IceCube. 4. Transient sources (e.g. GRBs) Use times of observed bursts to reduce background (can use cascades and look in Southern hemisphere). Optical/gamma follow up (ROTSE/MAGIC). Optical follow up of high energy neutrinos detected by IceCube Searches for neutrinos from GRBs with the IceCube 22 string detector and sensitivity estimates for the full detector Search for GRB neutrinos via a (stacked) time profile analysis. Search for neutrinos from GRBs with IceCube

19 The Physics (cont'd) 4. Neutrinos from DM annihilations Annihilations in Sun, Earth or galactic halo. Limits on SUSY or Kaluza Klein WIMPs. Results and Prospects of Indirect Searches for Dark Matter with IceCube Indirect Searches for WIMP Dark Matter from the Sun with AMANDA Search for Kaluza Klein dark matter with the AMANDA/IceCube detectors 5. Low energy neutrinos (Deep Core) WIMPs, neutrino oscillations, galactic sources Physics Capabilities of the IceCube DeepCore Detector Implementation of an active veto against atmospheric muons in IceCube DeepCore Fundamental Neutrino Measurements with IceCube Deep Core 6. Extremely High Energy (GZK) neutrinos Search for extremely bright events. Using empirical model for background muons from EHE air showers. The extremely high energy neutrino search with IceCube Energy scale calibration using comic ray induced muon bundles measured by the IceCube detector with IceTop coincident signals

20 7. Tau neutrinos High energy s background free. Characteristic signatures (double bang, lollipop) require km scale detector. Search for high energy tau neutrinos in IceCube 8. MeV neutrinos from supernovae Give increase of apparent noise Supernova search with the AMANDA/IceCube neutrino telescopes 9. Exotic physics Magnetic monopoles (slow or relativistic), SUSY (stau pairs), TeV gravity (black hole production).

21 Old, energy consuming, difficult to maintain AMANDA 24/ / Pioneer, Prototype, Subdetector Switched off, but still producing results!

22 Point source search in AMANDA (7 years) Likelihood test statistic using position and energy (number of OMs). R.Abbasi et al, Phys Rev D79, (2009) Significance Maximum significance p=95% (Probability of 3.38 or more from a fluctuation somewhere, determined by randomising events in azimuth) No signal! (Also no detection from pre defined sources, or in search for extended sources using same VLV T, Athens 13 15data) October 2009

23 Indirect DM search in AMANDA (7 years) J.Braun et al. (ICRC09) Use the 7 year point source data sample to look for excess from WIMP annihilations in the Sun (no energy in likelihood test) ν n µ 0.8 deficit in Sun direction No wimps!

24 Point source search with IceCube IC22 significance map of Northern Hemisphere Warm spot at r.a , dec 11.4 Some excitement... Probability of such a fluctuation somewhere in the sky is p =1.3%. Not significant! Astrophysical Journal Letters 701 (2009) L47 L51 arxiv

25 Looking up IC22 R.Lauer et al. arxiv IC40 J.Dumm et al. (ICRC09) It is possible to extend the search for neutrino point sources to the Southern Hemisphere by selecting large energy events which stand out against the CR muon background Neutrino background Uniform zenith population after cut on muon energy Muon background cos cos Sensitivity range depends on declination

26 Point source search with 40 strings Results for 6 months of data. Final result with 13 months soon! J.Dumm et al. (ICRC09) 6796 upgoing events downgoing events Highest significance at r.a dec All sky p value is 61%. Not significant!

27 IC40 six months result for source list Interesting sources selected in advance to reduce trial factor Source Name Cyg_OB2 MGRO_J MGRO_J Cas_A IC443 Geminga Crab_Nebula 1ES_ ES_ C66A H_ BL_Lac Mrk_501 Mrk_421 W_Comae 1ES_ M87 S5_ M82 3C_ C_ C_38.41 PKS_ PKS_ PKS_ C_273 NGC_1275 Cyg_A IC-22_maximum nothing! Ra, Dec (deg) ( , ) ( , ) ( , 6.269) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , 2.052) ( , ) ( , ) ( , ) p-value Source Name Sgr_A* PKS_ Cen_A PKS_ PKS_ PKS_ QSO_ PKS_ QSO_ C279 Ra, Dec (deg) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) ( , ) p-value most significant Quoting p values only when less than 0.5 (no negative fluctuations) Overall p value for 39 sources is 62%. Not significant!

28 Sensitivity to an E spectrum from a neutrino point source 2

29 Search for time dependent point sources Likelihood approach using observed EM emission (IC22) M.Baker et al. (ICRC09) Periodic sources Flaring sources No significant signal!

30 Neutrino triggered multimessenger astronomy IceCube sends real time alerts when multiple neutrinos are detected from same direction within a time window. AGN flare? MAGIC (Whipple/VERITAS) GRB/SN? A. Franckowiak et al. (ICRC09) ROTSE

31 Diffuse extraterrestrial neutrino flux or just atmospheric neutrinos? (all flavours) Three flavour flux, assuming (,, ) = (111) e

32 Search for GRB neutrinos 41 Northern Hemisphere bursts in IC22 Mostly SWIFT Limits pre cursor E (GeV) prompt Abbasi et al., arxiv submitted to ApJ Model neutrino flux depending on burst parameters and use unbinned likelihood approach in space, time, and energy. With Fermi bursts (more and with higher energy), and bigger detector, IceCube will be sensitive to GRBs if they are the dominant source of cosmic rays.

33 Indirect search for Dark Matter Look for neutrinos from annihilation of WIMPs caught in dense regions ZZ W+W qq l+l...? Comments s Use two extreme assumptions, + hard channel W W bb soft channel Solar wimp population tends to be in equilibrium in SUSY models. rate independent of ann, depends only on capture Annihilation rate in halo scales with ann. does not have to be a SUSY neutralino

34 Solar WIMP search with IC22 R.Abbasi et al. PRL 102, (2009) arxiv No excess from the Sun The limit is set based on a likelihood ratio between tested signal strength and and best fit (Feldman Cousins). cos(space angle from Sun position)

35 Limits on muon flux and spin independent capture cross section for solar WIMPs Red= IC22 Blue=AMANDA, 7 years Filled areas=allowed in MSSM Excluded by direct searches (spin indep.) soft hard 1000 times or more below SI limit from direct det. expts

36 Re interpreting solar WIMP searches for Kaluza Klein dark matter M.Danninger, K.Han, J.Braun (ICRC09)

37 Future Deep Core (being installed) Acoustic test system (SPATS) Radio propsal (ARA)

38 The Deep Core low energy extension Central 7 standard strings + 6 additional ones, giving fine instrumentation (x10 effective PE area) in central 15 megatonnes of IceCube Additional strings High QE DOMs (Hamamatsu R7081 mod) Deep Core Dust layer 350m Depth 2100m 2450m 1750m 1850m (veto) DOM spacing 7m (instead of 17m) String spacing 72m (instead of 125m) One such string has been deployed. Full Deep Core, surrounded by three (vertical) layers of standard strings will be in the ice by spring!

39 Deep Core veto 1. No causally connected early hits in surrounding detector (active veto region). 2. A well reconstructed starting point inside the fiducial volume. Gives a rejection factor of ~106 for atmospheric muons. Preliminary!

40 Deep Core veto Reconstructed vertex positions Muons Neutrinos z r Preliminary!

41 Deep Core neutrino effective area At trigger level IceCube + Deep Core IceCube D.Grant, PSU

42 Deep Core physics WIMP search Southern Hemisphere sources SNR neutrinos

43 Deep Core neutrino physics D.R. Grant et al. (ICRC09) Neutrino oscillations at high energies with high statistics Other possibilities Tau appearance (more cascade like events) 2 sin 2 13 = 0.1 no osc. m2 = ev2 osc. True E Mass hierarchy (difficult!) ~ 20 in one year # DOMs hit

44 Extending IceCube to extreme energies To detect neutrinos with extreme energies (GKZ) a vast sensitive volume is needed Askaryan effects Low attenuation Too expensive (too much attenuation)

45 Results from SPATS (South Pole Acoustic Test System) F.Descamps at al. (ICRC09) Four aoustic strings in upper 500m of IceCube holes + retrievable pinger. Measured sound speed, noise, and attenuation. Transient noise Attenuation length More studies/measurements to understand attenuation and evaluate expected performance for physics in hybrid array.

46 ARA Askaryan Radio Array Proposed radio array at South Pole Experience from test setup (AURA) Depth 200m (cheap) Spacing ~ 500m 1km ( attenuation length O(km)) Sensitive volume > 250 km3 GZK evts per year ~10

47 Summary IceCube is growing both outwards and inwards. Watch out!

48 Backup Slides

49 Effective areas for neutrinos Averaged over 4 sr IC86 trigger level IC22

50 E-2 Sensitivity Past, Present, Future Preliminary 40-string Discovery MACRO Potential 5σ in 50% of trials SK IC22 AMANDA-II 7 yr ANTARES Phys. Rev. D 79, (2009) 40-string Sensitivity Flux excluded at 90%cl 80-string Sensitivity Based on 40-string analysis 50 Jon Dumm, ICRC 2009

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