Sb for gamma / hadron separation in SWGO

INDIRA D. VERGARA QUISPE; P M HANSEN; LUKAS NELLEN; A.G. MARIAZZI; DIEGO GABRIEL MELO

Nagoya

Conferencia; 38th International Cosmic Ray Conference (ICRC2023); 2023

The Southern Wide-field Gamma-ray Observatory (SWGO) is an international collaboration work-ing on a ground-based gamma-ray observatory that will be located in the southern hemisphere.A crucial step in the analysis is to identify the showers produced by gamma rays and separatethem from the abundant background of hadronic showers. In this work, we propose to adapt theobservable, 𝑆 𝑏 , used successfully to composition studies in the Pierre Auger Observatory to theSWGO detector. This observable takes into account the signal and the position of each triggereddetector. It characterizes the shape of the lateral distribution of the signal, which depends on thenature of the primary particle. The value of 𝑆 𝑏 is therefore suited to identify gamma inducedshowers and to reject the more frequent hadronic showers. This analysis has been performedusing a scaling factor to link the observable, 𝑆 𝑏 , between the central and outrigger array. Also weexplore how this new observable improves the separation of primary proton and gamma-inducedair showers in terms of the merit factor.