Strangeness Enhancement in Event Generators*

Cosmic ray air showers and their associated cascades of hadronic daughter particles are often studied using Monte Carlo simulations of hadron-nucleus collisions. However, these simulations often fail to account for high muon fluxes observed in data collected from cosmic ray observatories (such as the Pierre Auger Observatory), a problem known as the Muon Puzzle. In this work, I study how such event generators (namely Pythia 8.308, EPOS-LHC, and Sibyll-2.3) account for strangeness enhancement (increased production of strange hadrons), a possible physical explanation for the Muon Puzzle at TeV energies. By simulating up to 100,000 proton-proton collisions at both 7 TeV and 13 TeV energies in all three event generators, I computed charged particle multiplicity classes based on definitions used in experimental analyses conducted by the ALICE collaboration (2017). I then computed yields ratios of strange particle counts for all three event generators at both energy levels for each multiplicity class to investigate whether strangeness enhancement was simulated in these event generators, which would show up as an increase in strangeness as a function of the multiplicity class. As expected, strangeness enhancement was observed in EPOS-LHC and not observed in Pythia 8.308 and Sibyll-2.3, where this effect is not physically modeled. These results and the analysis code that I wrote will be used in future LHCb studies and similar collider experiments to compare simulated strangeness with experimental strangeness production in data and will help to discern which event generators are useful representations of real-life hadron collision physics.