Measurement of the atmospheric muon flux with a 4 GeV threshold in the ANTARES neutrino telescope

TL;DR

This paper introduces a new method to measure the deep-sea atmospheric muon flux using coincidence signals in the ANTARES neutrino telescope, with an energy threshold of about 4 GeV, accounting for background sources like 40K decay and bioluminescence.

Contribution

A novel coincidence-based measurement technique for muon flux in deep-sea neutrino detectors, calibrated with natural 40K decay signals.

Findings

Muon flux dependence on depth measured

Calibration of detector efficiency using 40K decay

Effective background discrimination achieved

Abstract

A new method for the measurement of the muon flux in the deep-sea ANTARES neutrino telescope and its dependence on the depth is presented. The method is based on the observation of coincidence signals in adjacent storeys of the detector. This yields an energy threshold of about 4 GeV. The main sources of optical background are the decay of 40K and the bioluminescence in the sea water. The 40K background is used to calibrate the efficiency of the photo-multiplier tubes.