Cosmic Muon Modulation Analyses with Borexino

The Borexino Experiment is situated at the Laboratori Nazionali del Gran Sasso and aims for the measurement of low energetic solar neutrinos. Even though the cosmic muon flux is reduced by a factor 10⁶ due to the 3800 mwe. of rock overburden at the experimental side, a residual cosmic muon flux of (3.41±0.01).10^-4 m^-2 s^-1 with a mean energy of 270 GeV is still present. These muons are detected by a highly efficient muon veto. Most of the cosmic muons reaching the detector are produced in the decay of pions that originate from collisions of the primary cosmic radiation with atoms of the atmosphere. Since only pions that decay in flight without undergoing any interactions before produce muons with enough energy to reach the detector, a seasonal modulation of the cosmic muon flux is expected due to density changes in the atmosphere that alter the mean free path of the pions. In this talk, an analysis of the cosmic muon flux based on almost 10 years of data from the Borexino experiment is presented. Besides the seasonal modulation, other periods are searched for and their significance is checked with the help of a Lomb-Scargle periodogram.