We study a possibility of the Higgs boson, which consists of an SU(2) doublet and a septet. The vacuum expectation value of a septet with hypercharge Y=2 is known to preserve the electroweak rho parameter unity at the tree level. Therefore, the septe
t can give significant contribution to the electroweak symmetry breaking. Due to the mixing with the septet, the gauge coupling of the standard-model-like Higgs boson is larger than that in the standard model. We show the sizable VEV of the Higgs septet can be allowed under the constraint from the electroweak precision data. The signal strengths of the Higgs boson for the diphoton and a pair of weak gauge boson decay channels at the LHC are enhanced, while those for the fermonic decay modes are suppressed. The mass of additional neutral Higgs boson is also bounded by the current LHC data for the standard model Higgs boson. We discussed the phenomenology of the multiply charged Higgs bosons, which come from the septet.
In this paper, the renormalization-group equations for the (flavor-conserving) CP-violating interaction are derived up to the dimension six, including all the four-quark operators, at one-loop level. We apply them to the models with the neutral scala
r boson or the color-octet scalar boson which have CP-violating Yukawa interactions with quarks, and discuss the neutron electric dipole moment in these models.
Current limit on the dark matter relic abundance may suggest that $|mu|$ should be smaller than prediction in the minimal supergravity scenario (mSUGRA) for moderate $m_0$ and $m_{1/2}$. The electroweak-ino parameter $M_1, M_2$ and $|mu|$ are then mu
ch closer to each other. This can be realized naturally in the non-universal Higgs mass model (NUHM). Since the heaviest neutralino ($tildechi^0_4$) and chargino ($tildechi^pm_2$) have significant gaugino components, they may appear frequently in the left-handed squark decay and then be detectable at the LHC. In such a case, we showed that the hierarchy of $M_1, M_2$ and $|mu|$ can be determined. In the light slepton mass scenario with non-vanishing lepton-flavor violation (LFV) in the right-handed sector, NUHM with small $|mu|$ corresponds to region of parameter space where strong cancellation among leading contributions to $Br(muto egamma)$ can occur. We showed that determination of electroweak-ino hierarchy plays a crucial role in resolving cancellation point of $Br(muto egamma)$ and determination of LFV parameters. We also discussed test of the universality of the slepton masses at the LHC and the implications to SUSY flavor models.
