Antarctic detector catches cosmic ray quirk that stumps physics models
Scientists using IceCube found that high-energy muons from cosmic rays match predictions, but low-energy muons don't—exposing a crack in widely used physics simulations. The discrepancy could reshape how researchers model particle interactions, affecting cosmic ray studies and potentially detector designs across the field.
Originaltitel: Measurement of the mean number of muons with energies above 500 GeV in air showers detected with the IceCube Neutrino Observatory
<p>We present a measurement of the mean number of muons with energies larger than 500 GeV in near-vertical extensive air showers initiated by cosmic rays with primary energies between 2.5 and 100 PeV. The measurement is based on events detected in coincidence between the surface and in-ice detectors of the IceCube Neutrino Observatory. Air showers are recorded on the surface by IceTop, while a bundle of high-energy muons (TeV muons) from the shower can subsequently produce a tracklike event in the IceCube in-ice array. Results are obtained assuming the hadronic interaction models Sibyll 2.1, QGSJet-II.04, and EPOS-LHC. The measured number of TeV muons is found to be in agreement with predictions from air-shower simulations. The results have also been compared to a measurement of low-energy muons by IceTop, indicating an inconsistency between the predictions for low- and high-energy muons in simulations based on the EPOS-LHC model.</p>