Seasonal variation of the underground cosmic muon flux observed at Daya Bay

The Daya Bay Experiment consists of eight identically designed detectors\nlocated in three underground experimental halls named as EH1, EH2, EH3, with\n250, 265 and 860 meters of water equivalent vertical overburden, respectively.\nCosmic muon events have been recorded over a two-year period. The underground\nmuon rate is observed to be positively correlated with the effective\natmospheric temperature and to follow a seasonal modulation pattern. The\ncorrelation coefficient $\\alpha$, describing how a variation in the muon rate\nrelates to a variation in the effective atmospheric temperature, is found to be\n$\\alpha_{\\text{EH1}} = 0.362\\pm0.031$, $\\alpha_{\\text{EH2}} = 0.433\\pm0.038$\nand $\\alpha_{\\text{EH3}} = 0.641\\pm0.057$ for each experimental hall.\n