Study of the relative mass and width of the Z boson dimuon decay, as a function of centrality, in PbPb collisions with CMS

In the aftermath of high-energy, non-central heavy-ion collisions, a very strong electromagnetic field is expected to be produced before the onset of the quark–gluon plasma (QGP). To characterize the strength of this field, it has been proposed that it could induce potentially measurable modifications to the width and invariant mass of the Z boson, with the effect expected to be maximal in semi-central collisions. We present the status of an ongoing study of the relative changes in the mass and width of the Z boson, as a function of collision centrality, in PbPb collisions, using data collected with the CMS detector.