NNLO QCD study of polarised W+W− production at the LHC

Abstract

Longitudinal polarisation of the weak bosons is a direct consequence of Electroweak symmetry breaking mechanism providing an insight into its nature, and is instrumental in searches for physics beyond the Standard Model. We perform a polarisation study of the diboson production in the pp →$$ {\mathrm{e}}^{+}{v}_{\mathrm{e}}{\mu}^{-}{\overline{v}}_{\mu } $$ e + v e μ − v ¯ μ process at NNLO QCD in the fiducial setup inspired by experimental measurements at ATLAS. This is the first polarisation study at NNLO. We employ the double-pole approximation framework for the polarised calculation, and investigate NNLO effects arising in differential distributions.

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

“…The calculation is performed in the STRIPPER approach [24][25][26]. The approach has already been applied in the calculation of NNLO QCD corrections to top-pair [27][28][29][30][31], inclusive jet [32], three-photon [15], W +c jet [33], identified B-hadron [34] and polarized W -pair [35] production at the LHC. A detailed description of the technical aspects of our implementation has been given in ref.…”

W+W− production at NNLO+PS with MINNLOPS

“…[60], using the q q → V V two-loop helicity amplitudes [118,119]. Recently, NNLO corrections were studied for polarized W + W − production [120]. Also NLO QCD corrections to the loop-induced gluon fusion contribution, which are formally of O(α 3 s ), were evaluated using the gg → V V two-loop helicity amplitudes of refs.…”

NLO EW and QCD corrections to polarized ZZ production in the four-charged-lepton channel at the LHC

“…In order to recover gauge invariance, we use a pole-approximation technique [82][83][84][85][86][87], whose details are discussed in sections 2.1 and 2.2. Another method that is often used to simulate the production and decay of unstable particles is provided by the narrow-width approximation [76][77][78]81].…”

“…Before presenting the numerical results of our calculation, it is worth recalling that the polarization structure of ZZ production at the LHC is expected to be rather different from the one of W + W − [79,81], in spite of the same contributing partonic channels. At LO, the differential cross-sections for on-shell ZZ production in q q annihilation can be written in terms of the CM energy squared s and the scattering angle θ in the CM frame,…”

“…The generation of polarized events in general multi-boson processes is available at LO in the MadGraph framework [75] via the spincorrelated narrow-width approximation [76][77][78]. The separation of polarized signals at the amplitude level has been extended to NLO QCD [79,80] and to NNLO QCD [81] for diboson production in the fully-leptonic channel. The growing interest in the polarization structure of di-boson production and the increased sensitivity to polarization observables have motivated us to extend these polarization studies to NLO EW.…”