image Ratio in Di-Hadron Correlations

Particle ratios are important observables used to constrain models of particle production in heavy-ion collisions. In this work we report on a measurement of the image ratio in the transverse momentum range image, associated with a charged trigger particle of image, in 0–10% central Pb–Pb collisions at image. The ratio is measured in the jet peak and in a region at large Δη separation from the peak (bulk region). The presented results are based on 14M minimum-bias Pb–Pb collisions, recorded by the ALICE detector. It is observed that the image ratio in the bulk region is compatible with the image ratio of an inclusive measurement, and is much larger than the image ratio in the jet peak. The image ratio in the jet peak is compatible with a PYTHIA reference, in which fragmentation in the vacuum is the dominant mechanism of particle production.