IceCube PMT efficiency measurement with atmospheric muons

Parallel talk presented at the XXI International Workshop on Neutrino Telescopes - Padova 29 September - 3 October 2025 (https://agenda.infn.it/event/44606/) On behalf of the IceCube Collaboration Abstract: The IceCube neutrino observatory - comprised of a cubic kilometer of ice instrumented with over 5000 photo-multiplier tubes (PMTs) - has achieved world-leading precision measurements of atmospheric neutrino oscillation parameters in recent years. Such measurements inherently perform a simultaneous optical calibration of the detector, constraining relevant systematic uncertainties such as the efficiency of IceCube's PMTs. Independent calibration of this quantity would reinforce future oscillation measurements. In this talk, an in situ PMT efficiency calibration method is presented, with atmospheric muons - detected abundantly in IceCube at several kHz - serving as a “standard candle” light source. A small sample of well-reconstructed, minimum ionizing muon events is procured, and used to measure the PMT efficiency. The current results of this analysis are presented, as well as other potential applications of the aforementioned muon event sample for data-driven validation of event reconstruction algorithms.