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“The Cosmic Ray composition in the knee region and the hadronic interaction models” G. Navarra

“The Cosmic Ray composition in the knee region and the hadronic interaction models” G. Navarra INFN and University, Torino, Italy For the EAS-TOP Collaboration. XIII International Symposium on Very High Energy Cosmic Ray Interactions Pylos Greece, 6 -12 September 2004. EAS-TOP at LNGS

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“The Cosmic Ray composition in the knee region and the hadronic interaction models” G. Navarra

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  1. “The Cosmic Ray composition in the knee region and the hadronic interaction models” G. Navarra INFN and University, Torino, Italy For the EAS-TOP Collaboration XIII International Symposium on Very High Energy Cosmic Ray InteractionsPylos Greece, 6 -12 September 2004

  2. EAS-TOP at LNGS Campo Imperatore 2000 m a.s.l. 820 g.cm-2 data taking: 1989-2000

  3. DIRECT EXP. KNEE The Cosmic Ray primary spectrum THE HIGH ENERGY GALACTIC RADIATION

  4. EAS-TOP Energy range from the direct measurements up to above the knee: Cosmic Ray primary spectrum & composition Verification of the hadronic physics DETECTORS: HADRONS ATMOSPHERIC C.l. ELECTROMAGNETIC MUONS (E > 1 GeV) + MUONS (E > 1.3 TeV) Deep underground GS labs.: MACRO, LVD

  5. EAS-TOP: THE CALORIMETER& MUON TRACKER 8 x 13 cm Fe layers; 144 m2 streamer + q. proportional tubes

  6. DETECTORS & METHODS Hadrons  p-spectrum @ E0 ~ 0.5 - 50 TeV Cherenkov light + TeV muons  p, He, CNO fluxes @ E0 ~ 100 TeV e.m.  spectrum in “knee” region E0 ~ 103 - 104 TeV e.m. + GeV muons  composition in “knee” region e.m. + TeV muons  composition in “knee” region Verifications of methods and HE physics used e.m.  anisotropies & search for gamma primaries  CORSIKA-QGSJET 

  7. Size and energy spectra: Ne Eo Astrop. Phys. 10 (1999) 1

  8. Ne-Nm distributions 3-component fit: L, CNO, H in DLogNe = 0.2 intervals of Ne c2 = Si (fci – fexpi)2/si2 fci = wLfsLi + wCNOfsCNOi + wHfsHi Simulations with g = 2.75 spectra L = “p” or “50%p + 50% He” ; CNO = N; H = Fe Fraction of events Fraction of events

  9. The composition in the ‘knee’ region gCNO ~ 2.75 gl > 3.1 gFe = 2.3 – 2.7 Mass group g Heavier primary spectra harder  Ek Z ?

  10. TeV muon multiplicity fits in MACRO (TeV m) L = p + He H = Mg + Fe L+H Measured

  11. EAS-TOP & MACRO (TeV m) L = p + He H = Mg + Fe Astrop. Phys., 20 (2004) 641

  12. < ln A > vs. E0

  13. particle and energy flux in p-p E. M. MACRO EAS-TOP

  14. The hadronic interaction models (CORSIKA) • Primary protons: • Nm Nea • = 0.820 ± 0.007 • = 0.792 ± 0.007 • = 0.789 ± 0.008 • = 0.77 ± 0.02

  15. Evolution of composition< Ne-Nm > aEXP= 0.907 ± 0.004 aEXTRCMP= 0.79 ± 0.02 QGSJET: agreement with extrapolated direct measurements! aMAX-VENUS= 0.820 ± 0.007 NO INTERACTION MODEL CAN ACCOUNT FOR THE INCREASING Nm vs. Ne WITHOUT INCREASING PRIMARY MASS

  16. Component dominating at the “knee”? JACEE RUNJOB EAS-TOP From “direct” measurements: JACEE RUNJOB He – p spectra similar RUNJOB He spectrum harder JACEE

  17. A different approach: EAS-TOP & MACRO Astrop. Phys., 21 (2004) 223 Proc. 28th ICRC, 1 (2003) 115

  18. MACRO and EAS-TOP are separated by 1100-1300 m of rock: Em 1.3 - 1.6 TeV EAS-TOP (Cherenkov detector): total energy through the amplitude of the detected Cherenkov light signal. MACRO (muondetector): EAS primaries with En > 1.3 TeV/n EAS geometry through the m track ( r ~ 20 m, q ~ 10 uncertainties)

  19. DATA SET September 1998 – May 2000 Tot. Time T = 208 h 5 telescopes exposure G 830 day m2 sr angular window: D : 16 < q < 58 , 127 < f < 210 MACRO events in T and D: 35814 with EAS-TOP in Dt = 7ms: 3830 (expected accidental events < 3.0) Event coincidence is established off-line (GPS system - sT < 1ms) Coincidence Peak tMACRO–t Cherenkov (ms) Dt = 7ms Dt = 7ms 7

  20. C.l. + TeV muon analysis p He Fe Mg CNO E ≈ 80 TeV Nmp ≈ NmHe E ≈ 250 Tev Nmp ≈ NmHe ≈ NmCNO C.l. yield: p ~ He ~ CNO

  21. p, He, CNO @ ~ 100-200 TeV p+He p+He+CNO x 10-7 m-2s-1sr-1TeV-1 EAS-TOP & MACRO data EAS-TOP & MACRO data + p-flux

  22. The Cherenkov light LDF WITH JACEE FLUX Test of energy release in the atmosphere of QGSJET: R = r (42 m) / r (134 m) = Ne (370 g/cm2) / Ne (505 g/cm2) (Rexp – Rth)/Rth = 0.14 ± 0.09

  23. Ne and Nm spectra Ne Nm

  24. Decreasing with increasing zenith angle Secq g1g2 Ik*107 Nk chi**2/df m-2s-1sr-1 1.00-1.05 2.56 2.96  0.06 1.1  0.1 6.08  0.03 7.8/11 1.05-1.10 2.56 2.86 0.05 1.3 0.2 5.95 0.04 8.4/11 1.10-1.15 2.56 2.84 0.04 1.0 0.1 5.95 0.04 5.3/11 1.15-1.20 2.56 2.82 0.08 0.8 0.2 5.92 0.06 7.6/11 1.20-1.25 2.56 2.92 0.09 0.5 0.1 5.94 0.05 4.6/11 1.25-1.30 2.56 2.75 0.07 1.4 0.4 5.62 0.07 2.8/11 chi**2/df (1slope) 1.00-1.05 3.21  0.06 3.42  0.10 1.2  0.3 4.65  0.10 10.4/10 18.7/12 1.05-1.10 3.18 0.08 3.45 0.10 1.4 0.2 4.65 0.10 9.3/10 20.7/12 1.10-1.15 3.18 0.09 3.40 0.20 0.6 0.2 4.75 0.15 6.9/10 9.9/12 1.15-1.20 3.12 0.15 3.4 0.10 1.6 0.5 4.55 0.15 5.9/10 14/12 • Nm Nea • = (ge –1) /(gm-1) = 0.7 – 0.8 In agreement with models • SAME BENDING COMPONENT ? Ne Nm 2 slopes Agreement inside errors (~ 30%)

  25. IF SAME BENDING COMPONENT in Ne and Nm spectra We can identify it. We construct for each component (p, He, CNO, Mg, Fe) the energy spectrum fitting the size spectrum in the region of the knee. From such energy spectra we construct for each component the corresponding Nm spectrum, to be compared with the measured one. The result of such comparison 

  26. Muon size spectrum: measured and expected for different primaries on the base of the Ne spectrum If “Knee” on Helium primaries Ek (He) = (3.5  0.3) 1015 eV VENUS QGSJET NEXUS

  27. The primary spectrum from EAS-TOP

  28. Natural evolution….. KASCADE-Grande

  29. KASCADE-Grande If : E k,Z = Z * E k,1 SEARCH FOR IRON “KNEE” AT ~ 1017eV PRIMARY COMPOSITION: 1016- 1018eV STUDY OF C.R. INTERACTIONS AT UHE N (> 1018 eV) ~ 250 (3 y data taking) At the threshold of Auger (High Resolution) EAS-TOP/KASCADE Eknee = 3 – 4 PeV P,He iron

  30. Hadron spectrum at 820 g/cm2 &comparison with sea level (1033 g/cm2) Calculated QGSJET Exp. KASCADE/EAS-TOP

  31. E0 = 0.5 – 50 TeVProton spectrum at TOP S(Eo) = (9.8  1.1stat  1.6sys) 10–5 (Eo/1000) –2.80  0.06 m-2 s-1 sr-1 GeV-1 He contribution subtracted Astrop. Phys. 19 (2003) 329

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