Possible Formation of QGP-droplets in Proton-Proton Collisions at the CERN Large Hadron Collider

Abstract

Proton-proton (pp) collisions have been traditionally used as a baseline measurement in the search for a deconfined state of matter in heavy-ion collisions at ultrarelativistic energies. The unprecedented collision energies that are available at the Large Hadron Collider (LHC) at the European Laboratory for Nuclear Research (CERN) have illuminated new challenges in understanding the possible formation of droplets of this deconfined matter of partonic degrees of freedom in hadronic collisions, especially in high-multiplicity events. Enhancement of multi-strange particles compared to pions, degree of collectivity, comparable freeze-out temperature with heavy-ion collisions, observation of a long-range ridge-like structure for high-multiplicity events are some of the experimental observations in this direction. In this article, we discuss some of the experimental observables and outline new theoretical directions to understand the possibilities of exploring the formation of QGP-droplets in pp collisions at the LHC.