UC Berkeley

This paper presents the measurements of π±$$\pi ^{\pm }$$, K±$$\mathrm {K}^{\pm }$$, p$$\text {p}$$ and p¯$$\overline{\mathrm{p}} $$ transverse momentum (pT$$p_{\text {T}}$$) spectra as a function of charged-particle multiplicity density in proton–proton (pp) collisions at s=13TeV$$\sqrt{s}\ =\ 13\ \text {TeV}$$ 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 pT$$p_{\text {T}}$$ range from 0.1 to 20 GeV/c$$\text {GeV}/c$$ and are done in the rapidity interval |y|<0.5$$|y|<0.5$$. The pT$$p_{\text {T}}$$-differential particle ratios exhibit an evolution with multiplicity, similar to that observed in pp collisions at s=7TeV$$\sqrt{s}\ =\ 7\ \text {TeV}$$, which is qualitatively described by some of the hydrodynamical and pQCD-inspired models discussed in this paper. Furthermore, the pT$$p_{\text {T}}$$-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.