Loop suppressed electroweak symmetry breaking and naturally heavy superpartners

A model is presented in which $\mathcal{O}(10\mathrm{TeV})$ stop masses, typically required by the Higgs boson mass in supersymmetric models, do not originate from soft supersymmetry breaking terms that would drive the Higgs mass squared parameter to large negative values but rather from the mixing with vectorlike partners. Their contribution to the Higgs mass squared parameter is reduced to threshold corrections and, thus, it is one loop suppressed compared to usual scenarios. New fermion and scalar partners of the top quark with $\mathcal{O}(10\mathrm{TeV})$ masses are predicted.

Figure 1

RG evolution of top Yukawa coupling, $y_t$, the Higgs quartic coupling in the SM, ${\lambda }_{h,\mathrm{SM}}$, and in the SM with electroweak gauginos and Higgsinos (indicated by dashed line). RG evolution of the tree level prediction for ${\lambda }_h$ in the MSSM is shown in shaded region with the solid line representing its maximum value, ${\lambda }_{h,\mathrm{SUSY}-\text{tree}}=(g_2^2+g_Y^2)/4$. The $m/M$ line and shaded region indicate the value required to obtain the correct $y_t(Q)$ for $\lambda =1\pm 0.1$ at $Q=(M^2+m^2{)}^{1/2}$.

Figure 2

The $m_{{\tilde{t}}_{1,2}}/M$ (left) and $m_{{\tilde{t}}_{3,4}}/M$ (right) plotted in the $m/M$-${\tilde{m}}_F^2/M^2$ plane, assuming ${\tilde{m}}_f^2=0$.

Figure 3

Contours of constant contribution to ${\tilde{m}}_{H_u}^2/|{\tilde{m}}_{H_u}^2{|}^{1/2}[\mathrm{GeV}]$ from threshold corrections plotted in the ${\tilde{m}}_F^2/M^2$-${\tilde{m}}_{\overline{F}}^2/M^2$ plane, for $M=23\mathrm{TeV}$, $\lambda =1$ ($m$ is fixed by the top quark mass) and ${\tilde{m}}_f^2=0$. Along the green line (and shaded area) $m_h=125\mathrm{GeV}$ ($\pm 1\%$) in our approximation. The matching scale is $Q=m_{{\tilde{t}}_{1,2}}$ ($\simeq 9\mathrm{TeV}$ in this case).

Figure 4

The same as in Fig. 3 plotted in the ${\tilde{m}}_F^2/M^2$-$M$ plane assuming ${\tilde{m}}_F^2={\tilde{m}}_{\overline{F}}^2$.