Higgs Boson Mass, Proton Decay, Naturalness and Constraints of LHC and Planck Data

Abstract

A Higgs boson mass $\sim 126$ GeV as determined by the LHC data requires a large loop correction which in turn implies a large sfermion mass. Implication of this result for the stability of the proton in supersymmetric grand unified theories is examined including other experiments constraints along with the most recent result on cold dark matter from Planck. It is shown that over the allowed parameter space of supergravity unified models, proton lifetime is highly sensitive to the Higgs boson mass and a few GeV shift in its mass can change the proton decay lifetime for the mode $p\to \bar νK^+$ by as much as two orders of magnitude or more. An analysis is also given on the nature of radiative breaking of the electroweak symmetry in view of the high Higgs boson, and it is shown that most of the parameter space of universal and non-universal supergravity unified models lies on the Hyperbolic Branch of radiative breaking of the electroweak symmetry, while the Ellipsoidal Branch and the Focal Point regions are highly depleted and contain only a very small region of the allowed parameter space. Also discussed are the naturalness criteria when the proton stability constraints along with the electroweak symmetry breaking are considered together. It is shown that under the assumed naturalness criteria the overall fine tuning is improved for larger values of the scalar mass with the inclusion of the proton stability constraint. Thus the naturalness criteria including proton stability along with electroweak symmetry breaking constraints tend to favor the weak scale of SUSY in the several TeV region. Implications for the discovery of supersymmetry in view of the high Higgs mass are briefly discussed.