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Report on UHE cosmic rays WG

Report on UHE cosmic rays WG. Piera L. Ghia IFSI-INAF, Torino, and LNGS-INFN, Assergi, Italy Tom Gaisser University of Delaware, USA. TeV Particle Astrophysics II University of Wisconsin, Madison. What we had in mind :

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Report on UHE cosmic rays WG

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  1. Report on UHE cosmic rays WG Piera L. Ghia IFSI-INAF, Torino, and LNGS-INFN, Assergi, Italy Tom Gaisser University of Delaware, USA TeV Particle Astrophysics II University of Wisconsin, Madison

  2. What we had in mind: Experimental overview over all the spectrum (from direct measurements up to highest energies/EAS indirect mea) Theoretical point of view CR interactions in the atmosphere Direct meas (balloons/satellites) EAS meas Interaction in air CR WG Summary

  3. Theoretical point of view CR interactions Came “for free” in the plenary session (P. Blasi, Open problems on the origin of cosmic rays) & S.Yoshida (EHE signals)WG: Acceleration at astrophysical shocksP.Blasi S.OstapchenkoN. Solomey (MIPP)+G. Catanesi (Hadroproduction @ CERN, plenary) CR WG Summary

  4. Experimental status of the art From PeV to EeVA.Haungs Direct Cherenkov @ kneeS.Wakeley Around and Above EeVB.DawsonC.FinleyM.TeshimaJ. Cronin (PS)Bai, Gaisser et al (poster) Direct measurementsS.Swordy CR WG Summary

  5. Below the knee Lower end of the spectrumDirect measurementsS.Swordy CR WG Summary

  6. CR history ACE (Advanced Composition Explorer, NASA, 1997-2000) measurements: CR materials & history (400 MeV energy range) CR lifetime from mea of secondary radionuclides (10Be, 26Al, 36Cl, 54Mn, and 14C) Time between nucleosynthesis and acceleration Isotopic abundances CR WG Summary S.Swordy

  7. CR lifetime from meas of secondary radionuclides: Namely, from the abundances of radioactive secondaries with t comparable with confinement time, relative to primaries t=15±1.6 Myr CR WG Summary S.Swordy

  8. Time between nucleosynthesis and accelerationand isotopic abundances Decay 59Ni to 59Co by electron capture. Cannot happen if the parent has been accelerated (electrons stripped off) ACE data indicate that the decay has happened -> time > life time of 59Ni has elapsed before acceleration (>7.4 104yrs) CR isotopic abundances ≈ 400 MeV/N very similar to Solar System But notable difference for 58Fe (excess due to Wolf-Rayet ejecta?) CR WG Summary S.Swordy

  9. Below the knee Towards the kneeDirect measurementsS.Swordy CR WG Summary

  10. H and He spectra Thin calorimeters (JACEE, RUNJOB, ATIC) Differences here: He intensity larger for Jacee than Runjob Magnetic spectrometers (AMS, BESS, CAPRICE…) Same magnetic rigidity spectra (parallel with E), power law CR WG Summary S.Swordy

  11. Heavier elements and composition Up to 1000 TeV/n Runjob: constant (but Jacee: mass increase towards the knee) Tracer (heavy nuclei), magnetic rigidity spectra, consistent with Runjob CR WG Summary S.Swordy

  12. To go further towards the knee:Ultra long duration balloon flightsCREAM S.Swordy Oxigen Carbon CR WG Summary

  13. I kneeEAS measurementsA.Haungs CR WG Summary

  14. I knee Questions: Knee position Composition @ knee CR anisotropy Spectrum structure CR WG Summary A.Haungs

  15. Experimental answers Studies on spectrum/composition from Kascade, EAS-TOP, Tibet Asg, Ooty… CR WG Summary

  16. Kascade Analysis depends crucially on interaction models Unfolding performed for Different interactions models (Sybill, QGSJET) Different low energy interaction models (Gheisha, Fluka) CR WG Summary A.Haungs

  17. Kascade Knee @ 5PeV A.Haungs CR WG Summary

  18. Tibet Tibet results Proton and Helium do not bend at the knee (already steeper than direct meas.) Fraction of nuclei heavier than He increases with E at the knee Knee due to component heavier than He CR WG Summary A.Haungs

  19. EAS-TOP EAS-TOP results Also in correlation with underground TeV muon detector MACRO CR WG Summary A.Haungs

  20. Composition around/above knee and max accelerated energy Composition results: knees for different components, rigidity dependent => Protons up to 1016 eV (>>max E predicted by diffusive shock acceleration) [and consequently Fe up to 1017eV] CR WG Summary P.Blasi

  21. Non linear particle acceleration required Paradigm for galactic CR origin: acceleration at non-relativistic shock waves developping in supersonic motion of the ejecta of SN explosion (similar shocks in AGN/radio lobes for Xgal CRs) Max E=balance between acceleration time and SN age. For a SN 1000 yrs old -> fractions of GeV!!!! (depends on D coefficient) CR acceleration possible only if D coeff much smaller near the shock -> self-generation of magnetic turbulence by the accelerated particles -> max E up to 1013-1014 eV (still too low) Non linear theories needed -> shock modifications (CR spectrum modifies spectrum of magnetic fluctuations, which in turn modifies diffusion and hence the CR spectrum. Amplification of magnetic field enhances B, that in turn enhances shock modification CR WG Summary P.Blasi

  22. II knee, dip ankle: towards EeVEAS measurementsA.HaungsB.DawsonT.Gaisser et al CR WG Summary

  23. Questions: Transition galactic/Xgalactic Iron knee Anisotropies CR WG Summary A.Haungs

  24. Experimental answers Spectrum/composition from Yakutsk, HIRES, Akeno, and in the near future from Kascade-Grande, Icetop-Icecube, Tale, Auger @1018 eV CR WG Summary

  25. Energy spectrum HIRES claims the evidence of a II knee CR WG Summary A.Haungs

  26. Composition HIRES claims the evidence of a II knee HIRES/MIA claims a change of composition @ II knee (lighter one) CR WG Summary A.Haungs

  27. New detectors, e.g. Kascade-Grande CR WG Summary A.Haungs

  28. New detectors, e.g. Icetop/Icecube 100 TeV - 1 EeV CR WG Summary

  29. New detectors, e.g. Auger at “low” energies Surface Array 1600 detector stations 1.5 km spacing 3000 km2 • Auger was primarily designed for energies beyond 1019eV • but significant aperture at lower energies Fluorescence Detectors 4 Telescope enclosures 6 Telescopes per enclosure 24 Telescopes total ~2/3 tanks in field, completed in early 2007. Routine data taking since Jan. 2004. CR WG Summary B.Dawson

  30. FD-only apertures for completed Auger.Trigger aperture. Significant aperture at lower energies SD aperture 3 tanks with TOT = 3TOT (fully efficient at ~ 3 EeV)4 tanks with TOT = 4TOT (fully efficient at ~ 7 EeV) CR WG Summary B.Dawson

  31. EeV and aboveEAS measurementsC. FinleyM.TeshimaJ.Cronin CR WG Summary

  32. HIRES • Stereo observations provide the sharpest angular resolution for searching for small-scale anisotropy • In simulations, 68% of events above 10 EeV are reconstructed within 0.6° of their true arrival direction • Monocular observations currently provide the largest exposure for measuring the energy spectrum • HiRes-I was built first and obtained almost three-years more data than HiRes-II • HiRes consists of two sites • 12 km apart in the Utah desert (US Army Dugway Proving Ground) • Rings of mirrors at each site observe night sky CR WG Summary C.Finley

  33. HiRes-I and HiRes-II Data Sets • Current analysis of HiRes-I • May 1997 - June 2005 • Current analysis of HiRes-II • Dec. 1999 - Aug. 2004 • HiRes-I has more exposure than HiRes-II • Include only pure monocular statistics for HiRes-I when doing fits CR WG Summary C.Finley

  34. Broken Power Law Fits • Fit Spectra to broken power law: • Allow break point to float • No break point: • Bad fit: c2=154 / 39 DOF • One break point: • Better fit: c2=67.0 / 37 DOF • Find Ankle at 4 EeV • Two break points: • Good fit: c2=40.0 / 35 DOF • Reduce c2 by 27 • HE break at 60 EeV CR WG Summary C.Finley

  35. Statistical Significance • Significance of observed events beyond break point compared with expected: • Expect 44.9 events • Observe 14 • P(14 ; 44.9) = 7x10-8 • 5s is 3x10-7 • 6s is 1x10-9 CR WG Summary C.Finley

  36. Search for possible sources: BL Lac Correlations • Six results which we wish to test with independent data (all objects with m<18): • Note: • These are not independent results: the samples overlap. • Analysis has been a posteriori, so F values are not true probabilities. • Must be tested with independent data • Data taking through March 2006 has yielded an independent data set ~ 70% of the current sample size: Analysis is ongoing R.U. Abbasi et al., Astrophys.J. 636 (2006) 680 [astro-ph/0507120] Fraction of MC sets with greater ln(R) value than data CR WG Summary C.Finley

  37. AGASA 0 4km Closed in Jan 2004 S(600) as energy estimator 111 Electron Det. 27 Muon Det. Atmospheric depth CR WG Summary M.Teshima

  38. Conversion to energy and spectrum 11 obs. / 1.3~2.6 exp. CR WG Summary M.Teshima

  39. Critical review of energy estimation and sepctrum • Acceptance of Array • AGASA fast simulation (based on empirical formula and toy simulation) • Based on CORSIKA M.C. • Essentially acceptance is saturated  No difference • Lateral distribution of showers • Lateral distribution determined by experiment • Lateral distribution estimated by Corsika M.C. •  No difference • Attenuation of S(600) • Attenuation curve determined by experiment • Attenuation curve estimated by Corsika M.C. • There is systematic difference of 10-20% CR WG Summary M.Teshima

  40. Preliminary spectra with recent Corsika ~10% ~15% No difference in Models and Compositions Energy shift to lower direction ~10% at 1019eV ~15% at 1020eV Above 1020eV 11events  5~6 events Featureless spectrum very close to E-3 CR WG Summary M.Teshima

  41. Arrival Direction Distribution >4x1019eV, q <50˚ • Isotropic in the large scale  Extra-Galactic origin • But, Clusters in small scale (x<2.5deg) • 1triplet and 6 doublets (2.0 doublets are expected from random) CR WG Summary M.Teshima

  42. Pierre Auger Observatory Hybrid EAS array under construction in Argentina 1600 detector stations 1.5 km spacing 3000 km2 4 fluorescence eyes (6 telescopes each) CR WG Summary J.Cronin

  43. Conversion to energy and spectrum S(1000) energy estimator Conversion to energy through FD data No montecarlo! ICRC 2005 CR WG Summary J.Cronin

  44. Galactic center, small scale anisotropy 5 deg 20 deg 2.2 deg Point-like source search, with different bin sizes +: GC Solid line: GP Dashed line: field of view limit for Agasa Small circle: SUGAR excess Large circle: AGASA excess CR WG Summary B.Dawson

  45. CR WG Summary J.Cronin

  46. Need for models Models relate cross sections and particle production Models treat proton-proton, pion-proton,kaon-proton… General caveat: calibrated at “low” energies, with fixed target data and extrapolated over many decades in E CR WG Summary

  47. Hadronic interaction models Main challenge for models: treatment of non linear interactions effects at high energies and small impact parameter • QGSJET I: Pomeron formalism • QGSJET II: + non linear effects (Pomeron-pomeron interactions) • Sybill 2.1: phenomenological description of “hard” screening • EPOS (Pomeron approach as QGSJET) • Black Disk Limit (BDL): semi-classical QCD • + other VERY phenomenological appoaches CR WG Summary S.Ostapchenko

  48. Important predictions for EAS • p-air cross sections • Inelasticity • Cosmic ray muons: • Multiplicity and EAS muon content • Spectra and flux CR WG Summary S.Ostapchenko

  49. e.g., p-air cross section predictions Results depend on calibration with spp data (10% uncertainties) LHC data (1% accurcay) will solve the problem (Totem/CMS results) CR WG Summary S.Ostapchenko

  50. Cosmic ray muons - multiplicity CR experiments would like to have more muons…(EAS arrays favor iron-dominated composition, fluorescence proton-dominated) CR WG Summary S.Ostapchenko

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