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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 M.Tamada Kinki University ISVHECRI2012, Berlin, 10~15 Aug. 2012
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
(Mt. Chacaltaya, 5200m, Bolivia) 32 blocks 45 scintillation counters
hadron calorimeter(burst detector) emulsion chamber
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
Air-shower Ne, age Burst Snb, nb(max) Family SE, ng, nh, R
EAS: CORSIKA+QGSJET01c, EPOS 1.99 etc Simulations Families : EM cascade(E≥1TeV) : Okamoto-Shibata Hadron-Pb : QGSJET Burst : GEANT4.9.2
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
(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.
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
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
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 )
Data of the other hybrid experiments ✔ Tibet AS-g experiment ✔ Tien-Shan experiment Air-shower & families
Distribution of nb(max)/Ne with family
Comparison with the other experiment Tibet AS-g Phys. Rev. D62 (2000) 072007 Chacaltaya
Ne - <nb(max)/Ne> with family
nb(max) – family energy QGSJET01c QGSJET-II-03
nb(max) – family energy SIBYLL2.1 EPOS1.99
No analysis on bursts vs. families in Tibet and Tien-Shan
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 ?
✔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) ]
inclusion of fluctuation of cross-section of hadron-Air interaction in CORSIKA
No fluctuation with fluctuation w=0.3
Hadron component e,g component Fluctuation of cross-section Increase of Hadron component No change of e,g component
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 ?