Enhanced Production of Multi-strange Hadrons in Proton-Proton Collisions

Strangeness enhancement is proposed as a signature of QGP formation in high-energy nuclear collisions. The observed relative yield enhancements of hadrons increase with the strangeness content but not with the mass and baryon number of the hadron. To understand this behavior, we have studied on the simulation models. We have found the models EPOS and AMPT are not able to explain simultaneously the effect of strangeness canonical suppression in low-multiplicity events and QGP-like effect in high-multiplicity pp collisions at LHC energies.