Measurement of charged hadron production in $Z$-tagged jets in proton-proton collisions at $\sqrt{s}=8$ TeV

Understand

The production of charged hadrons within jets recoiling against a $Z$ boson is measured in proton-proton collision data at $\sqrt{s}=8$ TeV recorded by the LHCb experiment.

• The charged-hadron structure of the jet is studied longitudinally and transverse to the jet axis for jets with transverse momentum $p_{\mathrm{T}}>20$ GeV and in the pseudorapidity range $2.5<\eta<4$.
• These are the first measurements of jet hadronization at these forward rapidities and also the first where the jet is produced in association with a $Z$ boson.
• In contrast to previous hadronization measurements at the Large Hadron Collider, which are dominated by gluon jets, these measurements probe predominantly light-quark jets which are found to be more longitudinally and transversely collimated with respect to the jet axis when compared to the previous gluon dominated measurements.