Orateur
Description
In the era of the upcoming Electron-Ion Collider (EIC), the importance of accurate modeling of deep inelastic scattering (DIS) events is ever increasing. We aim to improve the modeling of DIS by implementing multi-jet merging capabilities in Pythia, the most widely-used Monte Carlo (MC) event generator among the LHC experiments. Multi-jet merging allows the combination of parton shower algorithms with fixed-order perturbation theory. This approach combines the accurate modeling of logarithmically enhanced emissions in parton showers with hard jets described by QCD matrix elements. A key challenge in this procedure is to avoid double-counting of different event classes. Multi-jet merging algorithms have successfully been implemented for LHC-processes in many MC event generators. For DIS processes, merging algorithms are currently only available in the Sherpa MC generator, where they found significant contribution to jet cross sections from high-multiplicity events.
In our current project we have implemented DIS multi-jet merging in the Vincia parton shower algorithm in Pythia using hard scattering events generated with MadGraph5 and Sherpa. In this talk, we summarise the implementation of jet merging and compare the results of two different merging algorithms, CKKW-L and UMEPS, with experimental HERA data provided by H1 and ZEUS collaborations. We show that multi-jet merging is necessary for an accurate description of DIS jets in a wide range of photon virtuality $Q^2$. We quantify systematic uncertainties by varying the factorization, renormalization and jet merging scales.
