Using Z boson events to study parton-medium interactions in PbPb collisions

Understand

The spectra measurements of charged hadrons produced in the shower of a parton originating in the same hard scattering with a leptonically decaying Z boson, are reported in lead-lead (PbPb) and proton-proton (pp) collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV.

• Both PbPb and pp data sets are recorded by the CMS experiment at the LHC, and correspond to an integrated luminosity of 1.7 nb$^{-1}$ and 320 pb$^{-1}$, respectively.
• Hadronic collision data with one reconstructed Z boson candidate with the transverse momentum $p_\mathrm{T}$ $\gt$ 30 GeV/$c$ are analyzed.
• The Z boson constrains the initial energy and direction of the associated parton.