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UHECRs: Spectra, Composition & Arrival Distribution

UHECRs: Spectra, Composition & Arrival Distribution. Tom Jones University of Minnesota. Special thanks to Mike DuVernois, UM (Auger & ANITA). The CR Flux Spectrum. Galactic & extra-Galactic ~ 10 9 eV to > 10 20 eV. E -2.7. 32 orders of magnitude. E -3.1. 12 orders of magnitude.

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UHECRs: Spectra, Composition & Arrival Distribution

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  1. UHECRs: Spectra, Composition & Arrival Distribution Tom Jones University of Minnesota Special thanks to Mike DuVernois, UM (Auger & ANITA) KAW4, Daejeon

  2. The CR Flux Spectrum • Galactic & extra-Galactic • ~ 109 eV to > 1020 eV E-2.7 32 orders of magnitude E-3.1 KAW4, Daejeon 12 orders of magnitude

  3. All particle cosmic ray spectrum UHECR KAW4, Daejeon LHC ppCM ZeV Nagano & Watson 00

  4. Where and How? Below ~ (1018 Z) eV galactic magnetic fields control charged particle trajectories Expect transition from diffusive propagation Confinement at low energies to weak deflection Above ~ (few x 1019 Z) eV little local deflection quasi-isotropy suggests extragalactic origins At highest energies arrival directions may point to source direction KAW4, Daejeon

  5. Proton propagation limited by interaction With CMB photons (Greisen-Zatsepin-Kuzmin; GZK)1 Photo-pair production Photo-pion production Path limit:  is cross section  is fractional energy loss per collision 1Assuming ‘standard physics’ KAW4, Daejeon

  6. Resulting Propagation Limits Pair losses Pion losses CMB conditions matched to look back time, adiabatic losses Included Concordance CDM KAW4, Daejeon

  7. Observed High Energy Spectra AGASA: 11 events above 1020 eV Hayashida etal 1999 KAW4, Daejeon

  8. Spectrum above 0.1ZeV not yet clear HiRes Collab ‘02 KAW4, Daejeon

  9. Important for small statistics: photopion losses are discrete: GZK feature much less clear: arguments probably premature De Marco, Blasi & Olinto (APh, 20, 53 (2003)) KAW4, Daejeon

  10. Early AUGER SD spectral results Mantsch etal, ICRC 2005 KAW4, Daejeon

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  13. Where is the transition to EGCR? transition to extragalactic ? ankle: pair production dip KAW4, Daejeon LHC ppCM ZeV Nagano & Watson 00

  14. Potential reinterpretation of the ankle:p+CMB leads to 3 possible features Berezinsky etal 2005 KAW4, Daejeon

  15. Features are composition dependent Allard etal 2005 Universal spectrum? 2.2-2.3? Pure proton EGCR composition, =2.6 is best fit and a good reproduction of ankle with the pair production dip Mixed composition case, ==2.2-2.3 down to the ankle KAW4, Daejeon

  16. So, what composition? GCRs show increasing heavies around the knee Kaskade KAW4, Daejeon

  17. Typical Decomposition C,O,… He Fe knee p KAW4, Daejeon LHC ppCM ZeV Nagano & Watson 00

  18. On the other hand UHECR Composition could be almost all p Best Fit: 80% p; QGSJet 60% p; SIBYLL Abbasi etal, ApJ 2005 KAW4, Daejeon

  19. Especially top-down models generate UHE  &: Photon Fraction Limits (sec. muons) 16 Auger hybrid events Xmax Risse etal, ICRC 2005 KAW4, Daejeon

  20. Current limits still allow top-down models SHDM SUSY Busca etal 2006 KAW4, Daejeon

  21.  constraints will soon be better Auger SD 2 yrs, E > 20 EeV Auger coll. preprint KAW4, Daejeon

  22. Must be some  & ; eg photopion decay Top-down models especially prolific there ‘Cosmogenic’ propagation,  &  from p injection ~(1+z)m E-, E < Emax Example case m = 3,  = 1 zmax = 2 Emax varied Semikoz & Sigl, JCAP, 04, 03 (2004) KAW4, Daejeon

  23. NeutrinosANITA: The Askaryan Effect e- UHE event will induce an e/ shower: In electron-gamma shower in matter, there will be ~20% more electrons than positrons. Compton scattering:  + e-(at rest)   + e- Positron annihilation: e+ + e-(at rest)   +  Excess charge emits Cherenkov radiation in matter, including coherent microwaves lead KAW4, Daejeon

  24. Solar panels Antenna array ANITA Gondola & Payload Overall height ~8m Antarctic Impulsive Transient Antenna • NASA SR&T start in 2003 (ANITA-LITE, EM) • launch in ‘06-07, every two years after • UH (P. Gorham, C. Hebert, J. Learned, J. Link, S. Matsuno, P. Miocinovic, B. Stokes, G. Varner), UCI (S. Barwick, J. Nam), JPL (K. Liewer, C. Naudet), Ohio State U. (J. Beatty, R. Nichol), U. Del. (D. Seckel, J. Clem), UCLA (D. Saltzberg, A. Connolly), U.Minn. (M. DuVernois, E. Lusczek), Univ. Kansas (D. Besson) M. Rosen, Univ. of Hawaii Instantaneous balloon field of view KAW4, Daejeon

  25. Current Neutrino Limits: ANITA-Lite excludes Z-bursts: UHE-CB showers Future experiments will constrain GZK contributions Barwick etal PRL 2006 KAW4, Daejeon

  26. UHECR Anisotropies1? • AGASA and SUGAR report galactic center excess. • AGASA reports small scale clustering [should reflect source (cosmogenic) granularity @highest energies] . • Suggested correlations with AGNs/BL-Lac objects (several analyses), clusters, etc. 1Below ~50 EeV galactic magnetic deflections of charged CRs are at least several degrees KAW4, Daejeon

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  29. Auger: Sky Map of Data set Auger latitude= -36. Always sees South with limited coverage in North. Mantsch etal KAW4, Daejeon

  30. North  South Auger-S >60o Auger-N >60o KAW4, Daejeon Cronin, astro-ph/0402487

  31. Auger Results: Galactic Center KAW4, Daejeon

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  34. AGASA Small Scale Clustering for E >4x1019eV • Isotropic in large scale  Extra-Galactic • But, Clusters in small scale (Δθ<2.5deg) • 1triplet and 6 doublets (2.0 doublets are expected from random) • One doublet  triplet(>3.9x1019eV) and a new doublet(<2.6deg) Uchihori etal 2000 KAW4, Daejeon

  35. Auger All Sky Search for Flux Excess • No excess observed. KAW4, Daejeon

  36. BL Lac /UHECR Cross-correlations? logE>19.5 Gorbunov etal 2004 KAW4, Daejeon

  37. Independent analysis results vary Original claims + maximum Hires likelihood Abbasi etal 2006 KAW4, Daejeon

  38. Sometimes they agree: Reanalysis of Gorbunov etal data Abbasi etal 2006 KAW4, Daejeon

  39. Conclusions • UHECRs above 0.1ZeV exist, but data still • inadequate to establish GZK feature (or not). • Source energy index ~ 2.2 -2.6, depending • on composition • Transition point from GCR to EGCR not yet clear • UHECR composition consistent with all protons • New photon and neutrino measures should help resolve • these issues • Anisotropy hints (AGNs?), intriguing, but statistics still small • Stay tuned for coming data KAW4, Daejeon

  40. The End KAW4, Daejeon

  41. (Ultra-)High Energy Physics of Cosmic rays & Neutrinos • Neither origin nor acceleration mechanism known for cosmic rays above 1019 eV • A paradox: • No nearby sources observed • distant sources excluded due to GZK process • Neutrinos at 1017-19 eV required by standard-model physics through the GZK process--observing them is crucial to resolving the GZK paradox galactic extragalactic KAW4, Daejeon

  42. Model n fluxes(Protheroe review 1999) atmosphere AGN pg GRB GZK GeV WIMPs TDs MGUT KAW4, Daejeon

  43. Gurgen Askaryan Excess charge moving faster than c/n in matter emit Cherenkov Radiation Each charge emits field |E|  eik•r and Power  |Etot|2 In dense material RMoliere~ 10cm. <<RMoliere(optical case), random phases P N >>RMoliere(microwaves), coherent  P N2 Confirmed with Modern simulations + Maxwell’s equations: Halzen, Zas, Stanev, Alvarez-Muniz, Seckel, Razzaque, Buniy, Ralston, DuVernois, Gorham, McKay … KAW4, Daejeon

  44. Upward and Horizontal Air-shower Rates Versus Neutrino Cross-section HAS UAS KAW4, Daejeon

  45. KAW4, Daejeon

  46. Comparison of Detector Discovery Potential: [A]@tlive KAW4, Daejeon

  47. Energy losses for protons Berezinsky et al. 03 redshift pair GZK attenuation factor: Jobserved (E,z) = (E,z) x Jinjected(E) KAW4, Daejeon

  48. 29th ICRC Pune Auger Hybrid Paul Sommers (this conference) Log (E) = -0.79 + 1.06 Log(S38) E = 0.16 S381.06 (E in EeV, S38 in VEM) Uncertainty in this rule increases from 15% at 3 EeV to 40% at 100 EeV KAW4, Daejeon

  49. IceCube Yoshida et al PRD 69 103004 (2004) KAW4, Daejeon

  50. The Estimated Spectrum vs. Log(E) Error bars on points indicate Poisson statistical uncertainty (or 95% CL upper limit) based on the number of events. Systematic uncertainty is indicated by double arrows at two different energies. Horizontal: Systematic E. Vertical: Exposure uncertainty. KAW4, Daejeon

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