Higgs mass via type II seesaw mechanism

We show that the simplest supersymmetric scenario where a large Higgs mass can be attained at tree level for any ratio of the Higgs vacuum expectation values corresponds to the case where the neutrino masses are generated through the type II seesaw mechanism. This allows a standard model-like Higgs with mass around 125 GeV without assuming a heavy spectrum for the top squarks. We show that our results are consistent with the bounds coming from perturbativity up to the grand unified scale and discuss gauge coupling unification and possible signals at the Large Hadron Collider.

Figure 1

The tree-level Higgs mass versus ${\lambda }_1$ with parameters scanned as described in the text. The orange curve represents the upper bound on the tree-level mass, Eq. (5), with ${\lambda }_2=0$ and $\tan \beta =10$. To aid the eye, horizontal lines at 110 and 125 GeV are drawn in green and blue, respectively. The area outside the vertical red dashed lines becomes nonperturbative before the GUT scale under the assumptions discussed in the next section.

Figure 2

Curves of constant tree-level $M_h$ in the ${\lambda }_1-t_{\beta }$ plane. The area outside the vertical red dashed lines becomes nonperturbative before the GUT scale under the assumptions discussed in the next section.

Figure 3

Values of constant $M_h$ at the two-loop level in the $M_{{\tilde{t}}_R}-M_{{\tilde{Q}}_3}$ plane for zero left-right top squark mixing and for ${\lambda }_1=0.16$, 0.18, 0.20 in red solid, green dashed and blue dotted curves, respectively.

Figure 4

Unification of the gauge couplings in the complete model with the colored octet and the new vectorlike pair (upper) and the running of the Yukawa couplings relevant to the Higgs mass (lower). Yukawa couplings not shown are 0.1 at the TeV scale except for $f_{\nu }$, which is insignificantly small due to neutrino masses.