2,217 research outputs found
About gauge invariance in compactified extra dimensions
Gauge theories formulated in a space-time manifold that includes compact
extra dimensions can show a nontrivial gauge structure. Depending on whether
the gauge parameters propagate or not in the extra dimensions, two different
Kaluza--Klein theories can arise when the extra dimensions are compactified. A
comparison between these two possibilities, in the context of a five
dimensional theory, is presented from both the theoretical and phenomenological
viewpoints. The phenomenological implications of these theories are contrasted
by discussing the one--loop decay of the Higgs boson into two photons. It is
shown that the amplitude for this decay differs substantially from one approach
to the other and that such a difference is intimately related to gauge
invariance.Comment: 5 pages, 1 figur
Higgs mediated lepton flavor violating tau decays and in effective theories
The size of the branching ratios for the and decays induced by a lepton flavor violating Higgs
interaction is studied in the frame of effective field theories.
The best constraint on the vertex, derived from the know
measurement on the muon anomalous magnetic moment, is used to impose the upper
bounds and , which are more stringent than current experimental
limits on this class of transitions.Comment: 6 pages, 3 figure
Effective Lagrangian description of Higgs mediated flavor violating electromagnetic transitions: implications on lepton flavor violation
Higgs mediated flavor violating electromagnetic interactions, induced at the
one--loop level by a nondiagonal vertex, with and charged
leptons or quarks, are studied within the context of a completely general
effective Yukawa sector that comprises --invariant
operators of up to dimension--six. Exact formulae for the one--loop and couplings are presented and their related
processes used to study the phenomena of Higgs mediated lepton flavor
violation. The experimental limit on the decay is used to
derive a bound on the branching ratio of the
transition, which is 6 orders of magnitude stronger than the current
experimental limit. Previous results on the and decays are reproduced. The possibility of detecting signals
of lepton flavor violation at colliders is explored through the
reaction, putting special emphasis on the
final state. Using the bound imposed on the vertex by the current
experimental data on the muon anomalous magnetic moment, it is found that about
half a hundred events may be produced in the International Linear Collider.Comment: 18 pages, 12 figure
Higgs mediated Double Flavor Violating top decays in Effective Theories
The possibility of detecting double flavor violating top quark transitions at
future colliders is explored in a model-independent manner using the effective
Lagrangian approach through the () decays. A
Yukawa sector that contemplates invariants of up to
dimension six is proposed and used to derive the most general flavor violating
and CP violating and vertices of renormalizable type.
Low-energy data, on high precision measurements, and experimental limits are
used to constraint the and vertices and then used to
predict the branching ratios for the decays. It is found
that this branching ratios may be of the order of , for a
relative light Higgs boson with mass lower than , which could be more
important than those typical values found in theories beyond the standard model
for the rare top quark decays () or . %% LHC experiments, by using a total integrated luminosity of of data, will be able to rule out, at 95% C.L., DFV top quark
decays up to a Higgs mass of 155 GeV/ or discover such a process up to a
Higgs mass of 147 GeV/.Comment: 24 pages, 11 figure
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