arXiv:1901.05261
LU TP 19-06
MCNET-19-01
Eur.Phys.J. C79 (2019) 413

by: Helenius, Ilkka (Tubingen U.) et al.

Abstract:
We present a new framework for modeling hard diffractive events in photoproduction, implemented in the general purpose event generator Pythia 8. The model is an extension of the model for hard diffraction with dynamical gap survival in $\mathrm {p}\mathrm {p}$ and $\mathrm {p}\overline{\mathrm {p}}$ collisions proposed in 2015, now also allowing for other beam types. It thus relies on several existing ideas: the Ingelman–Schlein approach, the framework for multiparton interactions and the recently developed framework for photoproduction in $\gamma \mathrm {p}$ , $\gamma \gamma$ , $\mathrm {e}\mathrm {p}$ and $\mathrm {e}^+\mathrm {e}^-$ collisions. The model proposes an explanation for the observed factorization breaking in photoproduced diffractive dijet events at HERA, showing an overall good agreement with data. The model is also applicable to ultraperipheral collisions with $\mathrm {p}\mathrm {p}$ and $\mathrm {p}{\mathrm {Pb}}$ beams, and predictions are made for such events at the LHC.