Precise predictions for photon pair production matched to parton showers in GENEVA

We consider Zγ production in hadronic collisions and present the first computation of next-to-next-to-leading order accurate predictions consistently matched to parton showers (NNLO+PS). Spin correlations, interferences and off-shell effects are included by calculating the full process pp → ℓ+ℓ−γ. We extend the recently developed MiNNLOPS method to genuine 2 → 2 hard scattering processes at the LHC, which paves the way for NNLO+PS simulations of all diboson processes. This is the first 2 → 2 NNLO+PS calculation that does not require an a-posteriori multi-differential reweighting. We find that both NNLO corrections and matching to parton showers are crucial for an accurate simulation of the Zγ process. Our predictions are in very good agreement with recent ATLAS data.

Section: Discussionmentioning

confidence: 95%

Advancing MıNNLOPS to diboson processes: Zγ production at NNLO+PS

Lombardi

Wiesemann

Zanderighi

2021

“…This kick-started steady progress of incorporating higher QCD orders and/or a more accurate treatment of the other SM interactions . Apart from a few impressive examples [32,33], this progress has slowed in recent years, and is being complemented with improvements of all-order parton showers. Parton showers form the backbone of matching fixed-order calculations to event generators, by e.g.…”

Section: Jhep11(2021)041mentioning

confidence: 99%

Matching N3LO QCD calculations to parton showers

Prestel

2021

The search for new interactions and particles in high-energy collider physics relies on precise background predictions. This has led to many advances in combining precise fixed-order cross-section calculations with detailed event generator simulations. In recent years, fixed-order qcd calculations of inclusive cross sections at n3lo precision have emerged, followed by an impressive progress at producing differential results. Once differential results become publicly available, it would be prudent to embed these into event generators to allow the community to leverage these advances. This note offers some concrete thoughts on me+ps matching at third order in qcd. As a method for testing these thoughts, a toy calculation of e+e− → u$$ \overline{u} $$ u ¯ at $$ \mathcal{O} $$ O ($$ {\alpha}_s^3 $$ α s 3 ) is constructed, and combined with an event generator through unitary matching. The toy implementation may serve also as blueprint for high-precision qcd predictions at future lepton colliders. As a byproduct of the n3lo matching formula, a new nnlo+ps formula for processes with “additional” jets is obtained.

“…Inclusive diphoton production pp → γγ + X has been studied extensively at NNLO in QCD [1][2][3][4][5]. Prior work also includes NLO QCD corrections [6] or electroweak effects [7], as well as photon isolation [8].…”

Section: Introductionmentioning

confidence: 99%

NNLO QCD corrections to diphoton production with an additional jet at the LHC

Chawdhry

Czakon

Mitov

et al. 2021

We calculate the NNLO QCD corrections to diphoton production with an additional jet at the LHC. Our calculation represents the first NNLO-accurate prediction for the transverse momentum distribution of the diphoton system. The improvement in the accuracy of the theoretical prediction is significant, by a factor of up to four relative to NLO QCD as estimated through scale variations. Our calculation is exact except for the finite remainder of the two-loop amplitude which is included at leading color. The numerical impact of this approximated contribution is small. The results of this work are expected to further our understanding of the Higgs boson sector and of the behavior of higher-order corrections to LHC processes.