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IceCube EHE analysis Our findings and roadmap to analysis. Shigeru Yoshida For the EHE working group. DOM response to high NPEs. ATWD or FADC?. “ EHE specific ” response!. Estimated number of photo-electrons per DOM. Log 10 (FADC based estimated NPE ).
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IceCube EHE analysisOur findings and roadmap to analysis Shigeru Yoshida For the EHE working group
DOM response to high NPEs ATWD or FADC? “EHE specific” response! Estimated number of photo-electrons per DOM Log10 (FADC based estimated NPE) Red: DOM of which ATWD charge is larger Blue: DOM FADC is larger Log10 (ATWD based estimated NPE) Npe saturation Npe saturation Log10 (FADC estimated NPE) Log10 (ATWD estimated NPE) Log10 (MC Truth NPE) Log10 (MC Truth NPE)
t m contained contained Log Npe GZK m Atmospheric m GZK t E-1 fluxes 107 1010 [GeV] 107 1010 [GeV] 107 1010 [GeV] NPE Energy Distribution
NPE Distribution Distribution difference between the signals and background! GZK m GZK t Atmospheric m
Zenith Angle Distribution down up • Signals peak at horizontal direction • Background distribute over down-going region GZK m GZK t Atmospheric m
Preliminary Event Selection Atmospheric m GZK m GZK t
Event Rate with completed detector GZK m GZK t Atmospheric m GZK m GZK t Atmospheric m IceCube Preliminary GZK m0.35events/year GZK t0.31 events/year Atmospheric m0.033events/year GZK: S. Yoshida et. al. (1997) ApJ 479:547 (m=4, Zmax=4)
Roadmap to analysis Atmospheric m BG Energy GZK m/t Signal Empirical Model Extrapolate to signal domain Tune Npe IceSim IceSim In-Ice data Standard Candle 9-strings unblinded data Eff. Area Cos(zenith) Log(Npe) Cos(zenith) NDOM Energy Log(Npe) Log(Npe)
9-strings working data NDOM >80 NDOM >80 Npe>104 Npe>104
9-strings working data Needs statistics ! to understand Intensity(Npe, zenith), DOM response in EHE regime Npe>104 ~ 500 Events/yr
9-strings“EHE”REAL DATA Build Empirical Model Cos(zenith) IceSim Log(Npe) Muon bundles 1PeV bundle of 1000 muons (1TeV/muon) • Npe only wouldnotbe able to resolve tracks • We donotknow cosmic ray intensity in EHE • We donotknow cosmic ray composition in EHE • Corsika hasnotreconstructed AGASA/Auger data
Why no problem in unblinding? Signal stats in the following data is by far large. Almost independent confirmation!! Expected Event Rate [/year] Y2008 x 1.5 Y2007 x 2 This Year
This cut? Or this cut? This cut? Or this cut? Why no problem in unblinding? Background and Signals are so different in Energies (Npe’s) and cos(1st-guess zenith)
Sensitivity/Bound Quasi-differential method This is MODEL independent!! Bound: energy dependent!! S. Yoshida et. al. (2004) Phys. Rev. D 69 103004
Beyond Npe and First-guessEnergy/Geometry reco Waveform-based likelihood (proposed by Gary) Utilize unscattered photon hits? (suggested by Lutz in 2004) cos(1st guess q) cos(reco q) Including more non-contained events Log(Npe) Log(Energy)
Introducing “Yoshida” bottle(s) Your WG wins them if you publish your results earlier than anybody else! Our Bread and Butter Photo by David Boersma