Hadronic interaction model dependence in cosmic Gamma-ray flux estimation using an extensive air shower array with a muon detector

Observation techniques of high-energy gamma rays using air showers have remarkably progressed via the Tibet ASγ, HAWC, and LHAASO experiments. These observations significantly contributed to gamma-ray astronomy in northern sky’s sub-PeV region. Moreover, southern sky, ALPACA experiment is underway at 4,740 m altitude on Chacaltaya plateau Bolivia. This estimates flux from difference between number on-source off-source events by real data, utilizing detection efficiency calculated through Monte Carlo simulations, which turn depends hadronic interaction models. Even though cosmic-ray background can be experimentally estimated, this model dependence affects estimation efficiency. However, previous reports assumed that negligible not included it error estimation. Using ALPAQUITA, prototype ALPACA, we quantitatively evaluated models for first time. We evaluate interactions as less than 3.6 % typical performed ALPAQUITA; compared with other uncertainties such energy scale uncertainty range 6 300 TeV, dominated statistics. upper limit expected apply ALPACA.