5,852 research outputs found
Fermion masses and mixings from heterotic orbifold models
We search for a possibility of getting realistic fermion mass ratios and
mixing angles from renormalizable couplings on the Z_6-I heterotic orbifold
with one pair of Higgs doublets. In the quark sector, we find cases with
reasonable m_c/m_t, m_s/m_b, and V_{cb}, if we ignore the first family. In the
lepton sector, we can fit the charged lepton mass ratios, the neutrino mass
squared difference ratio, and the lepton mixing angles, considering all three
families.Comment: 4 pages, 2 figures, 5 tables; talk presented at PASCOS-05, Gyeongju,
May 30-Jun 4, 2005; to appear in the proceeding
LHC 750 GeV diphoton excess and muon
We consider implications of the diphoton excess recently observed at the LHC
on the anomalous magnetic dipole moment of the muon ,
hypothesizing that the possible 750 GeV resonance is a (pseudo)scalar particle.
The (pseudo)scalar-- interaction implied by the diphoton events
might generically contribute to via 2-loop Barr-Zee type diagrams in a
broad class of models. If the scalar is an singlet, the new
contribution to is much smaller than the current anomaly, ,
since the scalar can complete the Barr-Zee diagrams only through its mixing
with the Standard Model Higgs boson. If the (pseudo)scalar belongs to an
doublet in an extended Higgs sector, then by contrast,
can be easily accommodated with the aid of an enhanced Yukawa coupling of the
(pseudo)scalar to the muon such as in the Type-II or -X two Higgs doublet
model.Comment: 16 pages, added discussions about UV completions with vector-like
fermions as well as consequences for heavy Higgs searches and B-physics,
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