The Zγ transverse-momentum spectrum at NNLO+N3LL

Abstract

We consider the transverse-momentum ($p_T$) distribution of $Z{\hat{I}}^3$ pairs produced in hadronic collisions. Logarithmically enhanced contributions at small $p_T$ are resummed to all orders in QCD perturbation theory and combined with the fixed-order prediction. We achieve the most advanced prediction for the $Z{\hat{I}}^3$ $p_T$ spectrum by matching next-to-next-to-next-to-leading logarithmic (N${}^3$LL) resummation to the integrated cross section at next-to-next-to-leading order (NNLO). By considering ${\ell }^{+}{\ell }^{-}{\hat{I}}^3$ production at the fully differential level, including spin correlations, interferences and off-shell effects, arbitrary cuts can be applied to the leptons and the photon. We present results at the LHC in presence of fiducial cuts and find agreement with the $13$\,TeV ATLAS data at the few-percent level.

16 pages, 7 figures, 1 table