12/22/ Y.Gallant, 1 A.Garyaka, 2 A.D.Erlykin 5 L.Jones, 1 R.Martirosov, 2 N.Nikolskaya, 3 J.Procureur, 1 S.Ter-Antonyan 1 Yerevan Physics Institute 2 Moscow Physics Institute 3 Centre d Etudes Nucleaires Bordeaux-Gradignan, 4 Universite Montpellier II 5 University of Michigan GAMMA Experiment All-particle primary energy spectrum in the knee region or Does the GAMMA experiment detect the polar cap component at energies PeV?

12/22/20152 GAMMA Facility

12/22/20153 Energy estimator: if& then Statistic ErrorsMethodic Errors Let CORSIKA i=1,…10 4, A=1,…4  , All-Particle Energy Spectrum Event-by-event analysis and All-Particle Energy Spectrum

12/22/20154 CORSIKA6031(NKG) EAS Simulations E max =5·10 3 PeV  < 45 0  = -1.5 E e > 1 MeV E  > 150 MeV E  > 4 GeV (e  ) SIBYLL2.1 ApHeOFe E min (PeV) N = 4 x 1.5  10 4 GAMMA Experiment

12/22/20155 E 0 -E 1 plot GAMMA Experiment a1a1a1a11.03 a2a2a2a23.64 a3a3a3a a4a4a4a42.11 a5a5a5a56.44 a6a6a6a61.2 a7a7a7a 0.14 2222~1  2 min (E 0,E 1 ) x = Ln(N ch ),y = Ln(N  ), c = cos(  )

12/22/20156 / ( E PeV ) 0.5 (+0.10) (-0.17 )    = 0.13,  = 0.03   A (E)  (E) Verification

12/22/20157 The distributions of errors are Gaussian !

12/22/20158 Zenith Angular Distribution GAMMA Experiment R<50m,  <45 0

12/22/20159 All-Particle Energy Spectrum GAMMA05: R < 25m; Q < 30 0 GAMMA07: R < 50m; Q < 45 0 GAMMA Experiment

12/22/ Sharpness of the knee  1 = 2.7  2 = 3.2  = 2  = E, PeV E 2.7  F(E) Polar Cap Component Outer Gap Component MHD acceleration

12/22/ Fine structure and additional pulsar components, where Outer gap,  p,1 =1Polar Cap,  p,1 =2 MHD F 1 (X)  dF/dN ch, and F 2 (X)  dF/dN  for  < 30 0, R < 50m

12/22/ Shower Spectra GAMMA Experiment

12/22/ All-particle spectra and pulsar Fe component GAMMA Experiment

12/22/ CONCLUSION  All-particle energy spectrum are obtained using GAMMA facility EAS database. The all-particle spectrum in the range of statistical and methodical errors agrees with the same spectrum obtained using EAS inverse approach in 5-70 PeV energy region. High accuracies of energy evaluations and small statistical errors point out to the existence of explicit irregularity (bump) of energy spectrum in the PeV region. GAMMA Experiment  Multi-parametric event-by-event energy evaluation method provided high accuracies (10-15%) for energy evaluation of primary nuclei regardless of nuclei mass number in PeV energy region;  The bump can be associated with an additional Fe-component from magnetosphere of pulsars.

12/22/ GAMMA TEAM Thanks GAMMA Experiment