Measurement of anisotropies in cosmic ray arrival directions with the AMS Detector on the Space Station

Abstract

A measurement of the dipole anisotropy in the arrival directions of galactic positrons, electrons and protons has been performed with the Alpha Magnetic Spectrometer onboard the International Space Station using the first 5 years of data taking. Relative anisotropies in the positron to electron ratio and in the high rigidity to low rigidity protons are presented together with the absolute anisotropy on positrons, electron and protons. Results are consistent with isotropy and upper limits on the true dipole amplitude are computed. A 95% C.L. upper limit of $\delta < 0.02$ and $\delta < 0.005$ was obtained for positrons and electrons respectively in the energy range 16 to 350 GeV, and $\delta < 0.01$ for protons in the rigidity range from 300 to 1800 GeV.