20,637 research outputs found
Fermion mass hierarchy and new physics at the TeV scale
In this talk, I present a new framework to understand the long-standing
fermion mass hierarchy puzzle. We extend the Standard Model gauge symmetry by
an extra local U(1)_S symmetry, broken spontaneously at the electroweak scale.
All the SM particles are singlet with respect to this U(1)_S. We also introduce
additional flavor symmetries, U(1)_F's, with flavon scalars F_i, as well as
vectorlike quarks and leptons at the TeV scale. The flavon scalars have VEV in
the TeV scale. Only the top quark has the usual dimension four Yukawa coupling.
EW symmetry breaking to all other quarks and leptons are propagated through the
messenger field, S through their interactions involving the heavy vector-like
fermions and S, as well as through their interactions involving the vector-like
fermions and F_i. In addition the explaining the hierarchy of the charged
fermion masses and mixings, the model has several interesting predictions for
Higgs decays, flavor changing neutral current processes in the top and the b
quark decays, decays of the new singlet scalars to the new Z' boson, as well as
productions of the new vectorlike quarks. These predictions can be tested at
the LHC.Comment: 10 pages, 2 figures; Plenary talk presented at the 17th International
Conference on Supersymmetry and the Unification of Fundamental Interactions
(SUSY09) at Northeastern University, Boston, MA, 5-10 June, 200
Shaking during Ion-Atom Collisions
Shaking (shakeup + shakeoff) probabilities accompanying ion-atom collisions
are studied using hydrogenic wavefunctions for K-, L-, M- shell electrons in
the sudden approximation limit. The role of recoil velocity in the shaking
processes is discussed. Further, it is found that the suddenness of collision
between projectile and target nuclei plays a major factor in shaking of
respective atomic system than the recoil of nuclei.Comment: 10 page
Topflavor: A Separate SU(2) for the Third Family
We consider an extended electroweak gauge group: SU(2) SU(2) U(1) where the first and second generation of fermions couple to
SU(2) and the third generation couples to SU(2). Bounds based on heavy
gauge boson searches and current precision electroweak measurements are placed
on the masses of the new heavy gauge bosons. In particular we find that the
mass of the heavy W boson can not be less than 800 GeV. For some range of the
allowed parameter space, these heavy gauge bosons produce observable signals at
the Tevatron and LEP-II.Comment: LaTeX, 11 pages, some comments on FCNC interactions and single top
production added, additional references include
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