A measurement of the Michel parameters, η, ρ, ξ, ξδ, and the average ντ helicity, hντ, in τ lepton decays is described together with the first measurement of the tensor coupling in the weak charged current. The results are consistent with the V - A structure of the weak charged current in decays of the τ lepton.
Abstract
We present the production cross section for a lepton-neutrino pair at the Large Hadron Collider computed at next-to-next-to-next-to-leading order (N3LO) in QCD perturbation theory. We compute the partonic coefficient functions of a virtual W± boson at this order. We then use these analytic functions to study the progression of the perturbative series in different observables. In particular, we investigate the impact of the newly obtained corrections on the inclusive production cross section of W± bosons, as well as on the ratios of the production cross sections for W+, W− and/or a virtual photon. Finally, we present N3LO predictions for the charge asymmetry at the LHC.
Charged current cross section for massive cosmological neutrinos impinging on radioactive nuclei