Delta r and the W-boson mass in the Singlet Extension of the Standard Model

TL;DR

This paper investigates how adding a real scalar singlet to the Standard Model affects the W-boson mass prediction through electroweak precision parameters, providing constraints on the model using recent experimental data.

Contribution

It computes the electroweak parameter Delta r in the singlet extension and derives new bounds on model parameters from W-boson mass measurements.

Findings

Predicted W-boson mass aligns with experimental data within certain parameter regions.

Identified parameter space regions with the most stringent current experimental constraints.

Provided theoretical predictions for electroweak precision parameters in the singlet extension.

Abstract

The link between the electroweak gauge boson masses and the Fermi constant via the muon lifetime measurement is instrumental for constraining and eventually pinning down new physics. We consider the simplest extension of the Standard Model with an additional real scalar SU(2)_L x U(1)_Y singlet and compute the electroweak precision parameter Delta r, along with the corresponding theoretical prediction for the W-boson mass. When confronted with the experimental W-boson mass measurement, our predictions impose limits on the singlet model parameter space. We identify regions where these correspond to the most stringent experimental constraints that are currently available.