NLO QCD predictions for $Z+\gamma$ + jets production with Sherpa

Abstract

We present precise predictions for prompt photon production in association with a $Z$ boson and jets. They are obtained within the Sherpa framework as a consistently merged inclusive sample. Leptonic decays of the $Z$ boson are fully included in the calculation with all offshell effects. Virtual matrix elements are provided by OpenLoops and parton shower effects are simulated with a dipole parton shower. Thanks to the NLO QCD corrections included not only for inclusive $Z\gamma$ production but also for the $Z\gamma$ + 1-jet process we find significantly reduced systematic uncertainties and very good agreement with experimental measurements at $\sqrt{s}=8$ TeV. Predictions at $\sqrt{s}=13$ TeV are displayed including a study of theoretical uncertainties. In view of an application of these simulations within LHC experiments, we discuss in detail the necessary combination with a simulation of the $Z$ + jets final state. In addition to a corresponding prescription we introduce recommended cross checks to avoid common pitfalls during the overlap removal between the two samples.

20 pages, 15 Figures

References in corpus (8)

• Event generation with SHERPA 1.1
• Comparative study of various algorithms for the merging of parton showers and matrix elements in hadronic collisions
• OneLOop: for the evaluation of one-loop scalar functions
• The complex-mass scheme for perturbative calculations with unstable particles
• Soft Photon Radiation in Particle Decays in SHERPA
• Reweighting QCD matrix-element and parton-shower calculations
• A modified CKKW matrix element merging approach to angular-ordered parton showers
• W gamma production in hadronic collisions using the POWHEG+MiNLO method

Cited by in corpus (8)

• Event Generation with Sherpa 2.2
• Advancing MiNNLO${}_{\mathrm{PS}}$ to diboson processes: $Z\gamma$ production at NNLO+PS
• Measurement of the $Z(\to {\ell }^{+}{\ell }^{-})\gamma$ production cross-section in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Probing the Interactions of Axion-Like Particles with Electroweak Bosons and the Higgs Boson in the High Energy Regime at LHC
• Electroweak, QCD and flavour physics studies with ATLAS data from Run 2 of the LHC
• Search for a new pseudoscalar decaying into a pair of muons in events with a top-quark pair at $\sqrt{s}=13$ TeV with the ATLAS detector
• Exploring Higgs-Photon Production at the LHC
• Measurements of $Z\gamma +$jets differential cross sections in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector