Study of Nuclear Effects on Charm Production in Light-Ion Collisions

The onset of nuclear effects in light-ion collisions is studied by measuring the ratio of D0 meson production between NeNe and OO collisions at a center-of-mass energy per nucleon pair of 5.36 TeV recorded by the LHCb detector. The D0 meson yields are measured differentially in transverse momentum (pT) for 0.5<pT<20 GeV in the rapidity (y) region 2.0<y<4.5, and are normalized to the total number of recorded inelastic nucleus-nucleus collisions in each data sample. The resulting production ratio shows evidence of variation as a function of pT, which is inconsistent with predictions based on nuclear modification of nucleon structure alone. This measurement is consistent with the onset of quark-gluon plasma production with increasing nucleus size in high-energy nuclear collisions.