Undeground Muon Hall (GAMMA Experiment)  Undeground Muon Hall (GAMMA Experiment)

150 plastic scintillators (1x1x0.05 m3, muon carpet) disposed under 2500 g/cm2 of rock at the center of EAS ground-based array to detect EAS muon component with energy more than 5 GeV.
The expected accuracy of EAS truncated muon size reconstruction (within 50 m radius from EAS core) is about 20-35% for the muon size range 105-103 respectively.
   Muon carpet allows to select the high energy (~1015 eV) gamma showers (no-muon signal events), the multicore EAS muon events originated from hard jet productions at ~1016 eV, and improves the EAS inverse problem solution - that is the reconstruction of energy and kind of primary nucleus by detected EAS parameters.

 

CURRENT RESULTS (2007-2009)

Romen M. Martirosov, Samvel V. Ter-Antonyan, Anatoly D. Erlykin, Alexandr P. Garyaka, Natalya M. Nikolskaya, Yves A. Gallant and Lawrence W. Jones, "Galactic diffuse gamma-ray flux at the energy about 175 TeV", arXiv:0905.3593 [astro-ph] (2009). Submitted to the 31-th International Cosmic Ray Conference, Lodz, Poland (2009).

A.P. Garyaka, R.M. Martirosov, S.V. Ter-Antonyan, A.D. Erlykin, N. Nikolskaya, Y.A. Gallant, L. Jones, and J. Procureur:
"All-particle primary energy spectrum in the 3-200 PeV energy range"
Journal of Physics G: Nuclear and Particle Physics, 35 (2008) 115201.
available from: http://stacks.iop.org/0954-3899/35/115201 or arXiv:0808.1421 v1 [astro-ph] (2008).

A.P. Garyaka, R.M. Martirosov, S.V. Ter-Antonyan, N. Nikolskaya, Y.A. Gallant, L. Jones, J. Procureur. "Rigidity-dependent cosmic ray energy spectra in the knee region obtained with the GAMMA experiment". Astroparticle Physics, Volume 28, issue 2 (2007) p. 169 / available from: arXiv:0704.3200v1 [astro-ph].

PRELIMINARY DATA (2005)

S.V. Ter-Antonyan, R.M. Martirosov, A.P. Garyaka, V. Eganov, N. Nikolskaya, T. Episkoposyan, J. Procureur, Y. Gallant, L. Jones: "Primary Energy Spectra and Elemental Composition. GAMMA Experiment".
astro-ph/0506588 (2005).  and
S.V. Ter-Antonyan, Y.A. Gallant, A.P. Garyaka, L.W. Jones, R.M.Martirosov, N.M. Nikolskaya, J. Procureur: "All-particle primary energy spectrum in the knee region" Proceedings 29th ICRC, Pune, India, (2005). 

First Results (GAMMA-2004)

EAS muon size spectra (GAMMA Experiment)

GAMMA data:
Detected EAS muon truncated size spectra at different EAS sizes and different interaction models (presented to GAMMA workshop 2004).

 

 

The "strange" behavior of Ne-Nm plot at Nch>107 (workshop GAMMA).

 

 

Multicore EAS event (GAMMA experiment)

Example of the multicore EAS event detected by GAMMA underground muon scintillator carpet. 

According to the quark-parton model of particle production with large transverse momenta in hadron interactions, the events with large Pt are due to hard scattering of quark-parton (gluons) which then are hadronized in the form of jets. It follows from the dynamics of these processes that the jets produced by spectator quarks are located on the interaction axis, and the other two jets (or a jet and gamma-quanta) generated from the hard collision of quarks (or a quark with gluon) emit under large transverse momemta. If the jet longitudinal momentum xjet > 0.05, and the transverse momentum Pt >>1 GeV/c, then at the energy of collision ~1015 eV if a cosmic ray nucleon with an air atom nucleus, the hadronized hard jet from the fragmentation region will be a source of a subcore of EAS whose major core is produced by a jet of spectator quarks.

Presented event corresponds to primary energy E0 =7x1016 eV, xjet ~ 0.05 and Pt >20 GeV  (Samvel Ter-Antonyan Workshop GAMMA2004).