The charge-dependent directed flow of D*+ and D*- mesons and the calibration of the ZDC Q-vectors in Pb-Pb collisions at the LHC with ALICE

Abstract

The charge dependent directed flow ($v_{1}$) of \dstar mesons relative to the spectator plane was determined as a function of pseudorapidity using the ALICE detectors at the LHC in \PbPb collisions at \five (2015 data set). In contrast with the charge dependent directed flow measurements of \dzero mesons, no significant charge dependent directed flow was found within the limits of the statistical uncertainty in both the $3 < p_{\rm T} < 6 \, \si{GeV/\textit{c}}$ and $3 < p_{\rm T} < 36 \, \si{GeV/\textit{c}}$ transverse momentum regions. In order to perform the analysis in the 2018 \PbPb data set, reducing the statistical uncertainty, a calibration of the Q-vectors, built using data from the two ZDC detectors, must be performed. A new code was built to perform the calibration of the 2018 (and future) \PbPb data sets. The aim is to repeat this analysis improving the statistics. A more accurate analysis of the charge dependent directed flow may lead to constraints on theoretical models describing the development of the strong electromagnetic field produced in heavy ion collisions. These constraints are crucial to find a signal of the chiral magnetic effect in heavy ion collisions.