Updated Results on the UHECR Hotspot Observed by the Telescope Array Experiment
2019 July 22
The Telescope Array Experiment has observed an indication of intermediate-scale anisotropy in the UHECR arrival directions, called the Hotspot, with $E>57$ EeV around the Ursa Major using the first 5-year data during a period between May 2008 and May 2013 collected by the TA surface detector array. The chance probability of this hotspot in an isotropic cosmic-ray sky was calculated to be 3.4$\sigma$ (post trial). In this paper, we will report on an update of this result using the 11-year data collected by the TA surface detectors with more than doubled exposure since the first publication.