Anisotropy in the mass composition from the Telescope Array Surface Detector data
2019 August 20
The mass composition of the Telescope Array surface detector data is analyzed with the use of the Boosted Decision Trees (BDT) technique, which assigns one parameter $\xi$ for each event, which is then concequently used for the determination of the average atomic mass of the primary particle. Itself, $\xi$ parameter may be distributed unevenly across the sky and indicate the mass composition anisotropy of the ultra-high-energy cosmic rays. The sensitivity of the BDT-based mass composition technique to the possible anisotropies is tested with the use of the $\xi$ distribution for the proton and iron Telesope Array surface detector Monte-Carlo sets.