1,362 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,
journal versio
Implications of the measurements of B_s - B_s bar mixing on SUSY models
We derive constraints on the mass insertion parameters from the recent
measurements of B_s - B_s bar mixing, and discuss their implications on SUSY
breaking mediation mechanisms and SUSY flavor models. Some SUSY flavor models
are already excluded or disfavored by B_s - B_s bar mixing. We also discuss how
to test the SM and SUSY models in the future experiments, by studying other CP
violating observables related to b -> s transition, such as the time-dependent
CP asymmetry in B -> phi K_S and the direct CP asymmetry in B -> X_s gamma.Comment: 29 page
Sflavor mixing map viewed from a high scale in supersymmetric SU(5)
We study flavor violation in a supersymmetric SU(5) grand unification
scenario in a model-independent way employing mass insertions. We examine how
the quark and the lepton sector observables restrict sfermion mixings. With a
low soft scalar mass, a lepton flavor violating process provides a stringent
constraint on the flavor structure of right-handed down-type squarks. In
particular, mu -> e gamma turns out to be highly susceptible to the 1-3 and 2-3
mixings thereof, due to the radiative correction from the top Yukawa coupling
to the scalar mass terms of 10. With a higher scalar mass around the optimal
value, in contrast, the quark sector inputs such as B-meson mixings and hadron
electric dipole moment, essentially determine the room for sfermion mixing. We
also discuss the recent deviation observed in B_s mixing phase, projected
sensitivity of forthcoming experiments, and ways to maintain the power of
leptonic restrictions even after incorporating a solution to fix the incorrect
quark-lepton mass relations.Comment: 40 pages, updated using phi_s from HFAG, conclusion unchange
B0 - B0 bar mixing, B -> J/psi K_S and B -> X_d gamma in general MSSM
We consider the gluino-mediated SUSY contributions to B0 - B0 bar mixing, B
-> J/psi K_S and B -> X_d gamma in the mass insertion approximation. We find
the LL mixing parameter can be as large as |delta_{13}^d_{LL}| < 2*10^-1, but
the LR mixing is strongly constrained by the B -> X_d gamma branching ratio and
we find |delta_{13}^d_{LR}| < 10^-2. The implications for the direct CP
asymmetry in B -> X_d gamma and the dilepton charge asymmetry (A_{ll}) are also
discussed, where substantial deviations from the standard model predictions are
possible.Comment: 14 pages, 4 figure
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