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Possible composition of the primary particles at ultrahigh energies observed at the Yakutsk array. By L.G. Dedenko 1 , A.V. Glushkov 2 , G.F. Fedorova 1 , S.P. Knurenko 2 , A.K. Makarov 2 , L . T . Makarov 2 , M.I. Pravdin 2 , T.M. Roganova 1 , A.A. Saburov 2 , I.Ye. Sleptzov 2 - PowerPoint PPT Presentation

Text of By L.G. Dedenko 1 , A.V. Glushkov 2 ,

  • Possible composition of the primary particles at ultrahigh energies observed at the Yakutsk array

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • By L.G. Dedenko1, A.V. Glushkov2, G.F. Fedorova1, S.P. Knurenko2, A.K. Makarov2, L.T. Makarov2, M.I. Pravdin2, T.M. Roganova1, A.A. Saburov2 , I.Ye. Sleptzov21. M.V. Lomonosov Moscow State University, Faculty of Physics and D.V. Skobeltsin Institute of Nuclear Physics, Moscow, 119992,Leninskie Gory, Russian Federation2. Insitute of cosmic rays and aeronomy. Yakutsk, Russian Federation

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • Motivation Testing the overall CR spectrum formation scenarios

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • The dip scenario of the overall CR spectrum formation In the model of uniformly distributed extragalactic sources with a power law spectrum of generation, the proton flux must first decrease (a dip), then increase (a bump) and drop steeply (the GZK effect) [3, 4]. [3] Berezinsky V S and Grigorieva S I 1988 Astron. Astrophys. 199 1[4] Berezinsky V S, Gazizov A Z, Grigorieva S I 2006 Phys. Rev. D 74 043005

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • The ankle scenario

    In the alternative ankle scenario [6] the extragalactic component dominates at energies above 1019 eV. The CR composition in this scenario is considerably heavier at energies 1018 1019 eV

    [6] Wibig T and Wolfendale W 2005 J. Phys. G: Nucl. Part. Phys. 31 255

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • The scenario by Berezhko E G The peak of rather heavy composition is predicted at energies ~ 1017 eV followed by a sharp decrease of atomic number A within of the energy interval 1017 1018 eV. It is regarded as a signature of the transition from galactic to extragalactic CR. The second peak of heavy elements in the atomic number distribution is predicted at energy ~ 1019 eV. So a profound increase of heavy composition should be observed within the energy interval 1018 1019 eV [5]. [5] Berezhko E G 2009 Astrophys. J. 698 L138

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • Study of compositionStandard approach:The depth Xmax of shower maximum vs. E

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • Before LHC

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • After LHC

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • 23-d European cosmic ray symposiumConclusion by T. Pierog, KIT, Karlsruhe, Germany (03.07.2012)light composition is excluded at high energies

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • Question by Angela OlinteThe UHECR in CERNFebrary 2012do we have pure protons anywhere???

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • We believe the answer is Yes

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • Alternative approachTHE FRACTION OF MUONS at 600 m from the shower core: =s(600)/s(600) s(600) a signal in the underground detector s(600) a signal in the surface detector

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • Yakutsk arrayThe Yakutsk array includes the surface scintillation detectors (SD), detectors of the Vavilov-Cherenkov radiation, underground detectors of muons (UD) with suggested the threshold energy ~1 GeV. It was shown that the less energetic muons may hit the underground detectors.

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • Simulations Simulations of the individual shower development in the atmosphere have been carried out with the help of the code CORSIKA-6.616 [7] Heck D, Knapp J, Capdevielle J-N et al. 1998 CORSIKA: A Monte Carlo Code to Simulate Extensive Air ShowersReport FZKA 6019 Forschungszentrum Karlsruhe

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • Simulations Simulationsin terms of the models QGSJET2 [8] Ostapchenko S S 2006 Nucl. Phys. Rev. B (Proc. Suppl.) 151 143 and Gheisha 2002 [9] Fesefeldt H C 1985 GHEISHA program Technical report PITHA 85-02, III Physikalisches Institut, RWTH Aachen. Physikzentrum

    with the weight parameter =10-8 (thinning).

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • SimulationsThe program GEANT4 [10] The GEANT4 Collab. Available from http://geant4.web.cern.ch/geant4/support/gettingstarted.shtmlhas been used to estimate signals in the scintillation detectors from electrons, positrons, gammas and muons in each individual shower.

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • Study of the chemical composition

    Muon density with energies above 1 GeVfor the primary protons with the energy E: (600, >1 GeV)=aEbDecay processes are decreasing for higher energies E. b

  • Study of the chemical compositionMuon density for the primary nuclei with atomic number A (600)=aAcEb c>0 (c=1-b)QGSJET2: b=0.895, c=0.105 For Fe: A0.105=1.53

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • Study of the chemical compositionThe signals are calibratedin the surface detectors s(600)=Es(600)/Es(600)and in the underground detectors s(600)=Eu(600)/Eu(600)Es(600) and Eu(600) from the EAS particles Es(600) and Eu(600) from the one vertical muon

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • Standard approach of energy estimation at the Yakutsk array s(600) the signal at 600 m in the vertical EAS measured in VEMs (VERTICAL EQUIVALENT MUON) is used to estimate the energy E of EAS.

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • Standard approach of energy estimation at the Yakutsk arrayDATA:1. The CIC method to estimate s(600) from data for the inclined EAS. 2. The signal s(600) is calibrated with help of the Vavilov-Cherenkov radiation E=(4.6+-1.2)1017 s(600)0.98, eV

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • Standard AGASA approachLike AGASA:1. The CIC method to estimate s(600) from data for the inclined EAS.2. Calculation s(600) for EAS withthe energy E: E=(3+-0.2)1017s(600), eV

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • SpectrumData: s(600)= E/((4.6+-1.2)1017) Simulation: s(600)= E/((3.+-0.2)1017) The simulated signal larger!The fraction is less!

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • SpectrumData: s(600)= E/((4.6+-1.2)1017) Simulation: s(600)= E/((3.+-0.2)1017) The simulated signal larger!The energy spectra are differentfor these approaches.

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • QuestionIs it possible to increase the signal s(600) more, to be able to decrease the fraction ?

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • points Yakutsk data circles Yakutsk (calculation like AGASA) stars PAO

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • AnswerIn the formula E=a1017s(600)The coefficient a should be less than 4.6 and higher than 3 (difference by a factor 1.53). The magnitude a=3 leads to the maximal signal s(600) and the minimal value of the muon fraction.

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • ResultsResults of calculations

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • The fraction of muons in EAS calculated in terms of the QGSJET-II and Gheisha-2002d models for the primary protons (solid line) and the primary iron nuclei (dashed line) and observed at the YaA[11] (dots with error bars) versus the energy E.

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • QuestionWhere are protons?

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • Another questionAre the models used reliable?

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • At energies above 100 GeVQGSJET2?Kochanov A A, Sinegovskaya T S, Sinegovsky S I 2008 Astrop. Physics 30 219 Panov A D, Adams J H Jr, Ahn H S et al. 2007 Bull. Russ. Acad. Sci. Phys. 71 494

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • The energy spectrum of vertical muons

    The 23-European Symposium and the 32 Russian cosmic ray conference 3-7 July Moscow

  • Ratio R1 of the observed intensities( [21], - [22], [23], [24], [25],+ [26])of the vertical muons to the calculated muon intensityin terms of the QGSJET-II model vs. an impulse p of muons (A.Kochanov).

    The 23-European Symposium and the 32 Russian cosmic ray c