Data-driven method to quantify and correct the corner-clipping effect in segmented muon counters

Segmented muon detectors, such as the Underground Muon Detector (UMD) of the Pierre Auger
Observatory, can suffer from overcounting due to inclined muons generating signals in two adjacent
segments. This effect, known as "corner clipping", introduces a bias in the muon estimator that
increases with the zenith angle. To correct for this, the common approach is to parameterize the
bias as a function of the zenith and azimuth angles using air-shower and full-detector simulations.
This correction, which relies entirely on simulations, is then applied to the data. In this work, we
introduce a data-driven method to quantify and correct the corner-clipping effect. Although we
use the UMD of the Pierre Auger Observatory as an example, this procedure can be applied to any
segmented detector with time resolution.