The search of the anisotropy of the primary cosmic radiation by the difference method

Victor Pavlyuchenko,Anatoly Erlykin,Romen Martirosov,Natalia Nikolskaya,B Pattison

doi:10.1051/epjconf/201614503003

Abstract

On the basis of experimental data obtained in the knee energy region with the GAMMA array an anomaly has been found in the mass composition of primary cosmic rays coming from the region of the VELA cluster. We used an original difference method which has high sensitivity, stability against accidental experimental errors and the possibility to separate anomalies connected with the laboratory coordinate system from anomalies observed in the celestial coordinates. The multiple scattering of the charged particles in the galactic magnetic fields makes it possible to study regions of the sky outside the direct visibility of the array.

Highlights

The blind search of the anisotropy in the primary cosmic rays (PCR) mass composition has been made with experimental data (3.38 · 106events) obtained with the extensive air shower (EAS) array GAMMA, operated at an altitude of 3200 m above sea level on Mount Aragats in Armenia
The PCR mass composition at high energies is determined with large uncertainties by indirect methods studying various EAS characteristics and model dependent simulations
In this study we used the lateral age, S, of EAS where S is the experimental dimensionless parameter connected with the steepness of the lateral distribution function (LDF) of the charged EAS particles approximated by the so called NKG function [11]

Summary

Introduction

In this case the multiple scattering of particles does not prevent, but rather helps to study PCRs from sources outside the direct visibility of the array. To do so we searched for regions of the sky having the maximum difference of the mass composition for particles coming from the opposite directions.

Results

Conclusion