English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We discuss the impact of many previously neglected effects of higherdimensional operators when fitting to Electroweak Precision data (EWPD) in theStandard Model Effective Field Theory (SMEFT). We calculate the general case of$2 \rightarrow 2$ fermion scattering in the SMEFT to order$\mathcal{O}(\bar{v}_T^2/\Lambda^2)$ valid on and off the $Z$ pole, in themassless fermion limit. We demonstrate that previously neglected correctionsscale as $\Gamma_Z M_Z/\bar{v}_T^2$ in the partial widths extracted frommeasured cross sections at LEPI, compared to the leading effect of dimensionsix operators in anomalous $Z$ couplings. Further, constraints on leadingeffects of anomalous $Z$ couplings are also modified by neglected perturbativecorrections and dimension eight operators. We perform a minimal EWPD fit toillustrate the size of the error these corrections induce, when boundingleading effects. These considerations relax bounds compared to a naive leadingorder analysis, and show that constraints that rise above the percent level aresubject to substantial theoretical uncertanties. We also argue thatrenormalization group running global constraints expressed through $\chi^2$functions to a common scale, and then minimizing and performing a global fit ofall data allows more consistent constraints to be obtained in the SMEFT.

Towards consistent Electroweak Precision Data constraints in the SMEFT