  Signatures of the formation of a strongly interacting thermalized matter of
partons have been observed in nucleus-nucleus, proton-nucleus, and
high-multiplicity proton-proton collisions at LHC energies. Strangeness
enhancement in such ultra-relativistic heavy-ion collisions is considered to be
a consequence of this thermalized phase, known as quark-gluon plasma (QGP).
Simultaneously, proper modeling of hadronic energy fraction in interactions of
ultra-high energy cosmic rays (UHECR) has been proposed as a solution for the
muon puzzle, an unexpected excess of muons in air showers. These interactions
have center-of-mass collision energies of the order of energies attained at the
LHC or even higher, indicating that the possibility of a thermalized partonic
state cannot be overlooked in UHECR-air interactions. This work investigates
the hadronic energy fraction and strangeness enhancement to explore QGP-like
phenomena in UHECR-air interactions using various high-energy hadronic models.
A core-corona system with a thermalized core undergoing statistical
hadronization is considered through the EPOS LHC model. In contrast, PYTHIA 8,
QGSJET II-04, and SYBILL 2.3d consider string fragmentation without
thermalization. We have found that EPOS LHC gives a better description of
strangeness enhancement as compared to other models. We conclude that
adequately treating all the relevant effects and further retuning the models is
necessary to explain the observed effects.
