UC Berkeley

(Multi-)strange particle production rates and transverse momentum distributions are measured at midrapidity as a function of the charged-particle multiplicity density by the ALICE experiment at the CERN Large Hadron Collider (LHC), using proton-proton collisions at a center-of-mass energy of TeV. This study extends similar studies performed at TeV and TeV to a lower-energy regime, improving the statistical precision and extending the measurement to previously unexplored low-multiplicity regions. While , , and yields can be described with a linear multiplicity dependence within uncertainties, the yields follow a significantly faster than linear increasing trend. For all analyzed particles, the overall production rate is consistent with that observed at higher energy and at similar multiplicity densities. Transverse momentum distributions are observed to evolve with multiplicity. Several state-of-the-art QCD-inspired Monte Carlo models have been compared with the data, testing some recently introduced features to address the findings at higher energies. Models can qualitatively describe the transverse momentum spectra and the spectral ratio only if collectivity is introduced in the evolution of the system.