Multidifferential study of identified charged hadron distributions in $Z$-tagged jets in proton-proton collisions at $\sqrt{s}=$13 TeV

TL;DR

This paper presents the first measurements of jet fragmentation functions for identified charged hadrons in proton-proton collisions at 13 TeV, providing new insights into hadronization processes and transverse-momentum-dependent fragmentation functions.

Contribution

It introduces the first measurements of charged hadron fragmentation functions within jets recoiling against a Z boson at 13 TeV, including triple differential distributions.

Findings

Differences observed in distributions for various hadron species.

Data constrains transverse-momentum-dependent fragmentation functions.

Provides new insights into light-quark jet hadronization.

Abstract

Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a $Z$ boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 $< p_{\textrm{T}} < 100$ GeV and in the pseudorapidity range $2.5 < \eta < 4$. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb$^{-1}$. Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse-momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.