Radiatively Generated Maximal Mixing Scenario for the Higgs Mass and the Least Fine Tuned Minimal Supersymmetric Standard Model

TL;DR

It is argued that given the experimental constraints on the Higgs boson mass the leastfine-tuned parameter space of the minimal supersymmetric standard model is with negative top-squark masses squared at the grand unification scale, which alleviates constraints on possible models for supersymmetry breaking in which fine-tuning is absent.

Abstract

We argue that given the experimental constraints on the Higgs mass the least fine tuned parameter space of minimal supersymmetric standard model is with negative stop masses squared at the grand unification scale. While stop mass squared is typically driven to positive values at the weak scale, the contribution to the Higgs mass squared parameter from the running can be arbitrarily small, which reduces fine tuning of electroweak symmetry breaking. At the same time the stop mixing is necessarily enhanced and the maximal mixing scenario for the Higgs mass can be generated radiatively even when starting with negligible mixing at the unification scale. This highly alleviates constraints on possible models for supersymmetry breaking in which fine tuning is absent.

Figures (1)

• Figure 1: Renormalization group running of relevant SSBs for $\tan \beta = 10$ and GUT scale boundary conditions: $-A_t = M_3 = 200$ GeV, $m_{\tilde{t}}^2 = -(400 \, {\rm GeV})^2$ and $m_{H_u}^2 = 0 \, {\rm GeV}^2$. In order to have both mass dimension one and two parameters on the same plot and keep information about signs, we define $m_{H_u} \equiv m_{H_u}^2/\sqrt{|m_{H_u}^2|}$ and $m_{\tilde{t}}\equiv m_{\tilde{t}}^2/\sqrt{|m_{\tilde{t}}^2|}$.