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A systematic study of the hybrid experiment at Mt.Chacaltaya

This study presents a systematic analysis of the hybrid experiment conducted at Mt. Chacaltaya, focusing on air-shower characteristics and burst detectors. Data from diverse experiments are compared to evaluate burst-triggered families with varying energy levels and chemical compositions.

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A systematic study of the hybrid experiment at Mt.Chacaltaya

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  1. A systematic study of the hybrid experiment at Mt.Chacaltaya M.Tamada Kinki University ISVHECRI2012, Berlin, 10~15 Aug. 2012

  2. H.Aoki^1, K.Honda^2, N.Inoue^3, N.Kawasumi^4, N.Ochi^5, N.Ohmori^6, A.Ohsawa^7, H.Semba^8, M.Tamada^9 1 Faculty of Engineering, Soka University, Hachioji, Tokyo 192-8577, Japan 2 Faculty of Engineering, University of Yamanashi, Kofu 400-8510, Japan 3 Faculty of Science, Saitama University, Saitama 388-8570, Japan 4 Faculty of Education, University of Yamanashi, kofu 400-8510, Japan 5 General Education, Yonago National College of Technology, Yonago 683-8502, Japan 6 Faculty of Science, Kochi University, Kochi 780-8520, Japan 7 Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582, Japan 8 Faculty of Comprehensive Welfare, Urawa University, Urawa 337-0974, Japan 9 Faculty of Science and Engineering, Kinki University, Osaka 577-8502, Japan N.Martinic, R.Ticona Insitute de Investigaciones Fisicas, Universidad Mayor de San Andres, La Paz, Bolivia

  3. (Mt. Chacaltaya, 5200m, Bolivia) 32 blocks 45 scintillation counters

  4. hadron calorimeter(burst detector) emulsion chamber

  5. EAS-array: shower size, Ne time,theta, phi primary energy Hadron calorimeter: “burstdensity”, nb time,position sensitive to hadron component of the air-showers position,theta, phi Emulsion chamber: atmospehric family (ng,nh,SEg, SEh) high threshold energy (E≥2〜4TeV): sensitive to production spectra

  6. Air-shower Ne, age Burst Snb, nb(max) Family SE, ng, nh, R

  7. EAS: CORSIKA+QGSJET01c, EPOS 1.99 etc Simulations Families : EM cascade(E≥1TeV) : Okamoto-Shiｂata Hadron-Pb : QGSJET Burst : GEANT4.9.2

  8. EAS above the detector CORSIKA + QGSJET01c, EPOS1.99 etc. shower size Ne : NKG-option Ecut=0.3GeV for hadrons, muons Ecut=0.003GeV for e,gamma Thinning energy = 10 GeV (fixed) E0≥1015eV : proton & Fe primaries with power index -2.8 : proton-dominant (~40% proton, ~15% Fe) : heavy-dominant (~15% proton, ~40% Fe) Sampling : 40,000 primaries each

  9. (e,g) & hadrons in the families : E≥1TeV Atmospheric families:detection in the emulsion chamber EM-cascade : Okamoto-Shibata algorithm Hadron-Pb int. : QGSJET01c • electron number ---> spot darkness • shower transition on spot darkness • fitting using standard cascade curve :DT, E(g) showers of DT > 6 c.u. : hadron-induced ng, SEg, nh, SEh(g), <R>, <ER> etc.

  10. GEANT4.9.2: (Hadron-shower model : QGSP) applied to hadrons, muons, e,g of E≥10 GeV Calculation of Burst-density nb Scintillator (5cm plastic) response Deposit energy  particle number Sampling from approximated function n(particle,Eh,tanq), which reproduce GEANT4 results

  11. Burst density (nb): number of particles detected in scintillation counter / 0.25 m2 • Snb :sum of burst density • nb(max) :maximum burst density in 32 blocks Hadron Calorimeter (Burst detector) 0.25 m^2 32 blocks

  12. Ne ≥ 106 • nb(max) ≥ 104 • n_blk(nb≥100) ≥ 10 • R_AS_Bs ≤ 1m Selection of the events Chacaltaya: • 1037 events • 62 events with family • ( ng(≥2TeV)≥5 )

  13. air-showers vs. families

  14. SEg/Ne

  15. Data of the other hybrid experiments ✔ Tibet AS-g experiment ✔ Tien-Shan experiment Air-shower & families

  16. air-showers vs. bursts

  17. Distribution of nb(max)/Ne with family

  18. Comparison with the other experiment Tibet AS-g Phys. Rev. D62 (2000) 072007 Chacaltaya

  19. Ne - <nb(max)/Ne> with family

  20. Burstsvs. families

  21. nb(max) – family energy QGSJET01c QGSJET-II-03

  22. nb(max) – family energy SIBYLL2.1 EPOS1.99

  23. SEg/nb(max)

  24. SEg/Snb

  25. No analysis on bursts vs. families in Tibet and Tien-Shan

  26. Correlation between family- energy and burst-size is not well described by the models change of chemical composition doesn’t work ! ✔ change of x-distribution in p-A int. ? : not compatible with LHCf results !? ✔ large fluctuation of p-Air cross-section ? ✔ large fluctuation of inelasticity ? ✔ largefluctuation of charge states ?

  27. ✔hadronic cross-section fluctuation ? [ B.Blattel et al., PRD 47 (1993) 2761 ] ✔ nonexponential behaviour of cosmic-ray data by cross-section fluctuation [ G.Wilk & Z.Wlodarczyk, PRD 50 (1994) 2313, 32nd ICRC (2011, Beijing) ]

  28. inclusion of fluctuation of cross-section of hadron-Air interaction in CORSIKA

  29. No fluctuation with fluctuation w=0.3

  30. events with families

  31. Hadron component e,g component Fluctuation of cross-section Increase of Hadron component No change of e,g component

  32. summary 1. Ne – SEg: SEg/Ne gradually decreases with Neheavy component increases with Ne ? 2. Ne – nb(max) : well described by mixed chemical composition but burst size of the eventswith family is systematically larger than model calculation 3. nb(max)-SEg : No model can describecharacteristics of burst-triggered families. 4. Inclusion of fluctuationof h-Air cross-section improves the situation but not enough. 5. Another fluctuations are necessary !? fluctuation of inelasticity, charge states ?

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