Year: 2026
Type: preprint
Abstract: Prompt-photon predictions with experimentally relevant isolation criteria retain a residual dependence on parton-to-photon fragmentation functions, whose phenomenological uncertainties remain only weakly constrained. We present a pragmatic study of photon fragmentation functions extracted from Pythia parton-shower events and stored in LHAPDF grids. We briefly review the role of photon fragmentation in perturbative QCD and then construct shower-level estimates of the flavour-dependent functions $D^{\mathrm{PS}}_{γ/i}(z,μ_D)$ as functions of the photon momentum fraction $z$ and fragmentation scale $μ_D$. The extracted distributions show the expected qualitative hierarchy between quark and gluon channels and an increasing fragmentation contribution with scale. In parallel, we convert the commonly used BFG, GRV, and GDRG parameterizations into LHAPDF grids and study their interpolation. We find that the default logcubic interpolation in LHAPDF reproduces the non-trivial $z$- and scale-dependence of the tabulated fragmentation functions more faithfully than the linear interpolation commonly used in legacy implementations. We also define a simple collider-oriented envelope set, based on the BFG and GRV families. These results provide a portable baseline for future phenomenological studies and for more systematic extractions of photon fragmentation functions.
Source: arXiv (Cornell University)
Author: Neuwirth, Alexander Puck
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G2760725075, G4955048828, G6813585582
OpenAlex ID: W7203697561