Study of quark and gluon jet identification in photoproduction at EIC

Abstract

We investigate the substructure of jets produced in photoproduction events with center-of-mass energies $\sqrt{s} = 30\text{--}140$ GeV at the proposed Electron-Ion Collider (EIC). Events are generated using PYTHIA and contributions from direct and resolved photoproduction subprocesses are analyzed at different center-of-mass energies. Jets are reconstructed using longitudinally invariant $k_T$ algorithm within the FastJet framework. Substructure of quark- and gluon-initiated jets in the selected di-jet photoproduction sample is studied in detail by using jet-shape variables. Predictions for subjet multiplicities and integrated jet shapes are presented in the gluon-initiated and quark-initiated jets. These results demonstrate the feasibility of distinguishing quark and gluon jets in the photo-production events at the EIC and provide a baseline for further QCD studies.

Figures (12)

• Figure 1: Direct (a) and Resolved (b) Photoproduction Processes
• Figure 2: The $E_{T}$ and $\eta$ distribution of jets in the generated GG and QQ dijet photoproduction subsamples.
• Figure 3: The differential jet shape is the average fraction of the jet’s transverse energy $E_{T,jet}$ contained inside an annulus of radius r, centred around the jet-axis.
• Figure 4: Differential jet shape distribution $\rho(r)$ for GG (blue) and QQ (red) dijet photoproduction subsamples at different $ep$ energies in four pseudorapidity bins: $-1 < \eta < 0$ (top left), $0 < \eta < 1$ (top right), $1 < \eta < 1.5$ (bottom left), and $1.5 < \eta < 2$ (bottom right).
• Figure 5: Integrated jet shape distribution $\Psi(r)$ for GG (blue) and QQ (red) dijet photoproduction subsamples at different $ep$ energies in four pseudorapidity bins: $-1 < \eta < 0$ (top left), $0 < \eta < 1$ (top right), $1 < \eta < 1.5$ (bottom left), and $1.5 < \eta < 2$ (bottom right).