When heavy ions meet cosmic rays : potential impact of QGP formation on the muon puzzle

The deficit of muons in the simulation of extensive air showers is a long-standing problem and the origin of large uncertainties in the reconstruction of the mass of the high energy primary cosmic rays. Hadronic interaction models, re-tuned after early LHC data, have a more consistent description of the muon content among them but still disagree with data. Collective hadronization due to the formation of a quark gluon plasma (QGP) has already been studied as a possible cause for a larger production of muons under extreme conditions (rare, very central nuclear interactions), but without real success. However, in the view of the most recent LHC data, a collective hadronization phase might not only be limited to such extreme conditions. And because of its different ratio of electromagnetic to hadronic energy, a QGP may have the properties to solve the muon puzzle. This hypothesis is demonstrated using a theoretical approach and tested in a realistic way by the modification of hadronic model spectra in CONEX to mimic the production of a QGP also in less extreme conditions with a possible large impact on air shower physics.