Status of the Auger – Telescope Array surface detector cross-calibration effort (Auger@TA)

Auger@TA is a joint experimental program of the Telescope Array (TA) and the Pierre Auger Observatory (Auger), the two leading Ultra-High Energy Cosmic-Ray (UHECR) experiments located respectively in the northern and southern hemispheres. The aim of the program is to achieve a cross-calibration of the Surface Detector (SD) from both experiments. Auger and TA SD stations are based on different detection media and respond differently to the electromagnetic and muonic components of UHECR showers. In this presentation, we discuss the results of the first phase of the effort, a comparative response study of a pair of co-located Auger and TA SD stations deployed within TA. We will also discuss our plan for the second phase, which consists of the deployment of an independently-operated Auger hexagon (7 stations) inside TA to perform event-level comparisons.