Measuring nuclear modification factors for φ-mesons in p + Pb and Pb + Pb collisions in the ALICE experiment at the large hadron collider

Abstract

Investigations of light vector mesons allow us to understand the mechanisms of hadron production in more detail and to investigate the properties of the dense and hot medium formed in central collisions of heavy ultrarelativistic nuclei. One of the most useful objects for investigations are φ-mesons, since their properties are sensitive to such effects as strangeness enhancement, the restoration of chiral symmetry, and the loss of parton energy that accompanies a phase transition. To investigate these phenomena, meson production must be measured not only in collisions of heavy nuclei but in proton-proton and proton-nuclear collisions as well. Measurements in elementary nucleon-nucleon collisions are used as the basis for comparison to heavier interacting systems. The collision of light and heavy nuclei allows us to evaluate the effects of cold nuclear matter and to interpret the effects of a hot nuclear medium more precisely. Invariant differential production spectra of φ-mesons were measured in the ALICE experiment as a function of transverse momenta in p + p, p + Pb, and Pb + Pb interactions. The distributions of the nuclear modification factors were constructed for φ-mesons on the basis of these data.