A simple dirac prescription for two-loop anomalous dimension matrices.

A novel method to treat effects from evanescent operators in next-to-leading order (NLO) computations is introduced. The approach allows, besides further simplifications, to discard evanescent-to-physical mixing contributions in NLO calculations. The method is independent of the treatments of γ 5 and can therefore be combined with different renormalization schemes. We illustrate the utility of this result by reproducing literature results of two-loop anomalous dimension matrices for both | Δ F | = 1 and | Δ F | = 2 transitions.

Computing tools for effective field theories: SMEFT-Tools 2022 Workshop Report, 14-16th September 2022, Zürich.

In recent years, theoretical and phenomenological studies with effective field theories have become a trending and prolific line of research in the field of high-energy physics. In order to discuss present and future prospects concerning automated tools in this field, the SMEFT-Tools 2022 workshop was held at the University of Zurich from 14th-16th September 2022. The current document collects and summarizes the content of this workshop.

Confronting the vector leptoquark hypothesis with new low- and high-energy data.

In light of new data we present an updated phenomenological analysis of the simplified U 1 -leptoquark model addressing charged-current B-meson anomalies. The analysis shows a good compatibility of low-energy data (dominated by the lepton flavor universality ratios R D and R D ∗ ) with the high-energy constraints posed by p p → τ τ ¯ Drell-Yan data. We also show that present data are well compatible with a framework where the leptoquark couples with similar strength to both left- and right-handed third-generation fermions, a scenario that is well-motivated from a model building perspective. We find that the high-energy implications of this setup will be probed at the 95% confidence level in the high-luminosity phase of the LHC.

ε ' / ε in the Standard Model at the Dawn of the 2020s.

We reanalyse the ratio ε ' / ε in the Standard Model (SM) using most recent hadronic matrix elements from the RBC-UKQCD collaboration in combination with most important NNLO QCD corrections to electroweak penguin contributions and the isospin-breaking corrections. We illustrate the importance of the latter by using their latest estimate from chiral perturbation theory (ChPT) based on the octet approximation for lowest-lying mesons and a very recent estimate in the nonet scheme that takes into account the contribution of η 0 . We find ( ε ' / ε ) SM ( 8 ) = ( 17.4 ± 6.1 ) × 10 - 4 and ( ε ' / ε ) SM ( 9 ) = ( 13.9 ± 5.2 ) × 10 - 4 , respectively. Despite a very good agreement with the measured value ( ε ' / ε ) exp = ( 16.6 ± 2.3 ) × 10 - 4 , the large error in ( ε ' / ε ) SM still leaves room for significant new physics (BSM) contributions to this ratio. We update the 2018 master formula for ( ε ' / ε ) BSM valid in any extension beyond the SM without additional light degrees of freedom. We provide new values of the penguin parameters B 6 ( 1 / 2 ) ( µ ) and B 8 ( 3 / 2 ) ( µ ) at the µ -scales used by the RBC-UKQCD collaboration and at lower scales O ( 1 GeV ) used by ChPT and Dual QCD (DQCD). We present semi-analytic formulae for ( ε ' / ε ) SM in terms of these parameters and Ω ^ eff that summarizes isospin-breaking corrections to this ratio. We stress the importance of lattice calculations of the O ( α em ) contributions to the hadronic matrix elements necessary for the removal of renormalization scheme dependence at O ( α em ) in the present analyses of ε ' / ε .