Multiplicity dependence of $\pi $ , K, and p production in pp collisions at $\sqrt{s}=13$ TeV

This paper presents the measurements of ${\pi }^{±}$ , ${K}^{±}$ , $\text{p}$ and $\overline{p}$ transverse momentum ( ${p}_{\text{T}}$ ) spectra as a function of charged-particle multiplicity density in proton–proton (pp) collisions at $\sqrt{s}\phantom{\rule{4pt}{0ex}}=\phantom{\rule{4pt}{0ex}}13\phantom{\rule{4pt}{0ex}}\text{TeV}$ with the ALICE detector at the LHC. Such study allows us to isolate the center-of-mass energy dependence of light-flavour particle production. The measurements reported here cover a ${p}_{\text{T}}$ range from 0.1 to 20 $\text{GeV}/c$ and are done in the rapidity interval $|y|<0.5$ . The ${p}_{\text{T}}$ -differential particle ratios exhibit an evolution with multiplicity, similar to that observed in pp collisions at $\sqrt{s}\phantom{\rule{4pt}{0ex}}=\phantom{\rule{4pt}{0ex}}7\phantom{\rule{4pt}{0ex}}\text{TeV}$ , which is qualitatively described by some of the hydrodynamical and pQCD-inspired models discussed in this paper. Furthermore, the ${p}_{\text{T}}$ -integrated hadron-to-pion yield ratios measured in pp collisions at two different center-of-mass energies are consistent when compared at similar multiplicities. This also extends to strange and multi-strange hadrons, suggesting that, at LHC energies, particle hadrochemistry scales with particle multiplicity the same way under different collision energies and colliding systems.