NLO Standard model effective field theory for Higgs and EW precision data

A set of constructs, definitions, and propositions that present a systematic view of the Standard Model Effective Field Theory (SMEFT), i.e. how the influence of higher energy processes is localizable in a few structural properties which can be captured by a handful of Wilson coefficients.Comment: Proceedings for Loops and Legs in Quantum Field Theory, 24-29 April 2016, Leipzig, German

Precision Electroweak Tests of the Standard Model

The study of electron-positron collisions at LEP, together with additional measurements from other experiments, in particular those at SLC and at the Tevatron, has allowed for tests of the electroweak Standard Model with unprecedented accuracy. We review the results of the electroweak precision tests and their implications on the determination of the Standard Model parameters, in particular of the Higgs boson mass, and comment on the constraints for possible new physics effects.Comment: 16 pages 6 figures; to appear in a special issue of Physics Reports dedicated to CERN on the occasion of the laboratory's 50th anniversar

Single-W Production and Fermion-Loop Scheme: Numerical Results

The single-W production mechanism is synonymous to the electron-positron annihilation into electron, neutrino and a W boson with the outgoing electron lost in a small cone around the beam direction. It requires a Renormalization Scheme that preserves gauge invariance and fermion masses cannot be neglected in the calculation. A recently proposed generalization of the so-called Fermion-Loop scheme is applied to the evaluation of observables at LEP 2 energies. Single-W processes are dominated by a regime of low momentum transfer of the outgoing electron and any high-energy Renormalization Scheme fails to give the correct description of the scale. The Fermion-Loop scheme automatically converts all couplings of the theory into couplings that are running at the appropriate scale. Therefore, in addition to represent the only scheme fully justified on a field-theoretical basis, the Fermion-Loop is the best starting point to include radiative corrections into single-W production. Numerical results are presented, showing a decrease in the predictions that can be sizeable. There is no naive and overall rescaling of the e.m. coupling constant, in any pragmatic scheme, that can reproduce the Fermion-Loop results, at the requested accuracy, for all configurations and for all kinematical cuts.Comment: 27 pages(Latex), 7 figure

How well can we guess theoretical uncertainties?

The problem of estimating the effect of missing higher orders in perturbation theory is analyzed with emphasis in the application to Higgs production in gluon-gluon fusion. Well-known mathematical methods for an approximated completion of the perturbative series are applied with the goal to not truncate the series, but complete it in a well-defined way, so as to increase the accuracy - if not the precision - of theoretical predictions. The uncertainty arising from the use of the completion procedure is discussed and a recipe for constructing a corresponding probability distribution function is proposed

Recent Theoretical Developments in LEP 2 Physics

Recent theoretical developments in electron-positron annihilation into fermion pairs are summarized. In particular, two-fermion production, DPA for WW signal, single-W production and ZZ signalComment: 6 pages(Latex), 4 figures. To appear in Proceedings of ICHEP2000, Osaka, Japan, 27 July - 2 August 200

The Twofold Way, a Short Disquisition of LEP Physics

A condensed survey of various aspects of LEP 1 physics is presented with a critical examination of the ingredients that are available for theoretical predictions. A prototype of comparisons for 2f calculations can be found in hep-ph/9902452.Comment: 16 pages(Latex). To appear in the Proceedings of "XIVth International Workshop: High Energy Physics and Quantum Field Theory (QFTHEP99)", Moscow, Russia, 27 May - 2 June 199