# Vector-like Quark Interpretation of Excess in Higgs Signal Strength

## TL;DR

This paper proposes a vector-like quark extension to the Standard Model to explain a slight excess in Higgs signal strength and address discrepancies in bottom quark observables, fitting data better than the standard model.

## Contribution

It introduces a vector-like quark doublet with specific mixing properties that reduce the bottom Yukawa coupling and improve agreement with Higgs and LEP data.

## Key findings

- Reduced bottom Yukawa coupling improves Higgs signal fit.
- Enhanced Z-b coupling addresses LEP bottom asymmetry.
- Model aligns better with experimental data than the Standard Model.

## Abstract

There is a $+2\sigma$ deviation in the average Higgs-signal strength for all the $7+8+13$ TeV data up to Summer 2018. We find that a slight reduction of the bottom-Yukawa coupling can fit the data better than the standard model. We suggest an extension with a vector-like quark doublet, of which the right-handed component of $b'$ mixes nonnegligibly with the standard model $b$ quark. We show that the mixing would induce a reduction of the bottom Yukawa coupling. Simultaneously, the coupling of the $Z$ boson to the right-handed $b$ quark increases, which could reduce the forward-backward asymmetry of bottom production at LEP and bring it closer to the experimental value.