Putting standard model EFT fits to work

Sally Dawson,Samuel Homiller,Samuel D Lane

doi:10.1103/physrevd.102.055012

Sally Dawson, Samuel Homiller + Show 1 more

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https://doi.org/10.1103/physrevd.102.055012

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Abstract

The Standard Model Effective Field Theory (SMEFT) provides a consistent framework for comparing precision measurements at the LHC to the Standard Model. The observation of statistically significant non-zero SMEFT coefficients would correspond to physics beyond the Standard Model (BSM) of some sort. A more difficult question to answer is what, if any, detailed information about the nature of the underlying high scale model can be obtained from these measurements. In this work, we consider the patterns of SMEFT operators present in five example models and discuss the assumptions inherent in using global fits to make BSM conclusions. We find that including renormalization group effects has a significant impact on the interpretation of the results. As a by-product of our study, we present an up-dated global fit to SMEFT coefficients in the Warsaw basis including some next-to-leading order QCD corrections in the SMEFT theory.

Highlights

With the Higgs discovery in hand and the Standard Model (SM) field content complete, one of the primary goals of the LHC is to make precise measurements of SM processes, with the hope of testing its limitations
We perform a series of fits to Higgs, diboson, and electroweak precision observables (EWPOs) data with prior assumptions about the relationships between Standard Model effective field theory (SMEFT) coefficients that are motivated by our example models
We examine how fits to SMEFT coefficients that are predicated on patterns of coefficients generated in different UV complete models give information about the high scale physics

Summary

Introduction

With the Higgs discovery in hand and the Standard Model (SM) field content complete, one of the primary goals of the LHC is to make precise measurements of SM processes, with the hope of testing its limitations. As the search for new particles has been unsuccessful as yet, much attention has shifted towards precision measurements of Higgs processes. In this direction, the SMEFT (SM effective field theory) framework becomes very useful. The SMEFT is useful because it provides a consistent, gaugeinvariant theoretical interpretation of the data, in which higher order corrections can be included, and connects Higgs data with electroweak precision observables at the Z and W poles, diboson data, and top quark measurements. There have been numerous global fits to LHC and LEP data, yielding limits on the allowed values of the SMEFT coefficients [1,2,3,4,5], but far all of these fits are totally

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