Estimation of the Upper Limit for the Amplitude of the Dipole Anisotropy of the Total Flux of 25-Gev to 1-Tev Cosmic-Ray Electrons and Positrons

Abstract

Searches for the anisotropy of the total electron and positron fluxes in high-energy galactic cosmic rays are performed. Data collected by the PAMELA magnetic spectrometer from June 2006, when it was launched into Earth’s orbit, to 2016 were used for the respective analysis. The main event selection and a determination of particle arrival directions were accomplished by means of a position-sensitive microstrip calorimeter. A neutron detector was used to suppress additionally the background of protons and nuclei. An analysis of information obtained over a nearly ten-year period of measurements made it possible to set upper limits on the amplitude of the dipole anisotropy of the total electron and positron fluxes for two energy ranges, between 25 and 100 GeV and between 100 GeV and 1 TeV. These results supplement data from other satellite-borne experiments, AMS-02 and Fermi.