Abstract
Electroweak precision observables, being highly sensitive to loop contributions of new physics, provide a powerful tool to test the theory and to discriminate between different models of the underlying physics. In that context, the $W$ boson mass, $M_W$, plays a crucial role. The accuracy of the $M_W$ measurement has been significantly improved over the last years, and further improvement of the experimental accuracy is expected from future LHC measurements. In order to fully exploit the precise experimental determination, an accurate theoretical prediction for $M_W$ in the Standard Model (SM) and extensions of it is of central importance. We present the currently most accurate prediction for the $W$ boson mass in the Next-to-Minimal Supersymmetric extension of the Standard Model (NMSSM), including the full one-loop result and all available higher-order corrections of SM and SUSY type. The evaluation of $M_W$ is performed in a flexible framework, which facilitates the extension to other models beyond the SM. We show numerical results for the $W$ boson mass in the NMSSM, focussing on phenomenologically interesting scenarios, in which the Higgs signal can be interpreted as the lightest or second lightest CP-even Higgs boson of the NMSSM. We find that, for both Higgs signal interpretations, the NMSSM $M_W$ prediction is well compatible with the measurement. We study the SUSY contributions to $M_W$ in detail and investigate in particular the genuine NMSSM effects from the Higgs and neutralino sectors.
Highlights
Besides the solution of the μ-problem, there are additional motivations to study the Next-to-Minimal Supersymmetric extension of the Standard Model (NMSSM)
A further improvement of our results for the MSSM and the NMSSM is that they are based on contributions to ∆r that can all be evaluated at the correct input value for MW, i.e. MW(N)MSSM, while the evaluation in ref. [78] makes use of the fitting formula for MWSM [58]
The corresponding contribution to ∆r extracted from the fitting formula for MWSM is determined at the input value MWSM rather than MW(N)MSSM, while it is the latter that is needed for the evaluation in the (N)MSSM
Summary
We introduce the NMSSM and specify our notation. We focus on the particle sectors which differ from the MSSM. In addition to the two Higgs doublets of the MSSM, the NMSSM contains a Higgs singlet, S, which couples only to the Higgs sector.. Κ. Like in the MSSM, there is no CP-violation at tree-level in the couplings of the Higgs doublets. The new doublet-singlet couplings allow in principle for CP-violation at tree level, but we will not consider this possibility here. The mixing of the CP-even, CP-odd and charged Higgs fields occurring in the mass eigenstates is described by three unitary matrices U H , U A, and U C, where h1. The superpartner of the singlet scalar enlarging the NMSSM Higgs sector is called the singlino, S. It extends the neutralino sector with a fifth mass eigenstate. Which gives the mass eigenvalues ordered as mχ0i ≤ mχ0j for i < j
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