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

Through precision straits to next standard model heights

After the LHC Run 1, the standard model (SM) of particle physics has been completed. Yet, despite its successes, the SM has shortcomings vis-\`{a}-vis cosmological and other observations. At the same time, while the LHC restarts for Run 2 at 13 TeV, there is presently a lack of direct evidence for new physics phenomena at the accelerator energy frontier. From this state of affairs arises the need for a consistent theoretical framework in which deviations from the SM predictions can be calculated and compared to precision measurements. Such a framework should be able to comprehensively make use of all measurements in all sectors of particle physics, including LHC Higgs measurements, past electroweak precision data, electric dipole moment, $g-2$, penguins and flavor physics, neutrino scattering, deep inelastic scattering, low-energy $e^{+}e^{-}$ scattering, mass measurements, and any search for physics beyond the SM. By simultaneously describing all existing measurements, this framework then becomes an intermediate step, pointing us toward the next SM, and hopefully revealing the underlying symmetries. We review the role that the standard model effective field theory (SMEFT) could play in this context, as a consistent, complete, and calculable generalization of the SM in the absence of light new physics. We discuss the relationship of the SMEFT with the existing kappa-framework for Higgs boson couplings characterization and the use of pseudo-observables, that insulate experimental results from refinements due to ever-improving calculations. The LHC context, as well as that of previous and future accelerators and experiments, is also addressed.Comment: 19 pages, 3 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

Large-Angle Bhabha Scattering at LEP 1

A critical assessment is given of the theoretical uncertainty in the predicted cross-sections for large-angle Bhabha scattering at LEP 1, with or without t-channel subtraction. To this end a detailed comparison is presented of the results obtained with the programs ALIBABA and TOPAZ0. Differences in the implementation of the radiative corrections and the effect of missing higher-order terms are critically discussed.Comment: 10 pages, Late

Veltman, renormalizability, calculability

Dedicated to the memory of Prof. Veltman, one of the founding fathers of our discipline: his legacy lives on. Many times we have to turn back and follow his footprints to find the right path. After reviewing general aspects of high energy physics where he gave a seminal contribution we will introduce recent developments in the standard model effective field theory, showing how the whole movement from renormalization to predictions plays from Veltman to SMEFT.Comment: to appear in Acta Physica Polonica, 27 page