526 research outputs found
Top quark chromomagnetic dipole moment in the littlest Higgs model with T-parity
The littlest Higgs model with T-parity, which is called model, predicts
the existence of the new particles, such as heavy top quark, heavy gauge
bosons, and mirror fermions. We calculate the one-loop contributions of these
new particles to the top quark chromomagnetic dipole moment . We find that the contribution of the model is one order of magnitude
smaller than the standard model prediction value.Comment: latex files, 12 pages, 3 figure
Precise limits from lepton flavour violating processes on the Littlest Higgs model with T-parity
We recalculate the leading one-loop contributions to mu > e gamma and mu ->
eee in the Littlest Higgs model with T-parity, recovering previous results for
the former. When all the Goldstone interactions are taken into account, the
latter is also ultraviolet finite. The present experimental limits on these
processes require a somewhat heavy effective scale ~2.5 TeV, or the flavour
alignment of the Yukawa couplings of light and heavy leptons at the ~10% level,
or the splitting of heavy lepton masses to a similar precision. Present limits
on tau decays set no bounds on the corresponding parameters involving the tau
leptonComment: 41 pages, 11 figures; v3: matches published version in JHE
Photon-induced production of the mirror quarks from the model at the
The photon-induced processes at the provide clean experimental
conditions due to absence of the proton remnants, which might produce
complementary and interesting results for tests of the standard model and for
searching of new physics. In the context of the littlest model with
T-parity, we consider the photon-induced production of the mirror quarks at the
. The cross sections for various production channels are calculated and a
simply phenomenology analysis is performed by assuming leptonic decays.Comment: 20 pages, 10 figure
Effects of the littlest Higgs model with T-parity on Higgs boson production at high energy colliders
The Higgs boson production processes , , and
are very important for studying Higgs boson
properties and further testing new physics beyond the standard model() in
the high energy linear
collider(). We estimate the contributions of the littlest
Higgs model with T-parity( model) to these processes and find that the
model can generate significantly corrections to the production cross
sections of these processes.
We expect the possible signals of the model can be detected via these
processes in the future experiments.Comment: 9 pages, 2 figures, references adde
Minimal Flavour Violation and Beyond
Starting from the effective-theory framework for Minimal Flavour Violation,
we give a systematic definition of next-to-minimal (quark) flavour violation in
terms of a set of spurion fields exhibiting a particular hierarchy with respect
to a small (Wolfenstein-like) parameter. A few illustrative examples and their
consequences for charged and neutral decays with different quark chiralities
are worked out in some detail. Our framework can be used as a model-independent
classification scheme for the parameterization of flavour structure from
physics beyond the Standard Model.Comment: 17 pages, no figures, phenomenological discussion extended,
references adde
Muon to electron conversion in the Littlest Higgs model with T-parity
Little Higgs models provide a natural explanation of the little hierarchy
between the electroweak scale and a few TeV scale, where new physics is
expected. Under the same inspiring naturalness arguments, this work completes a
previous study on lepton flavor-changing processes in the Littlest Higgs model
with T-parity exploring the channel that will eventually turn out to be the
most sensitive, \mu-e conversion in nuclei. All one-loop contributions are
carefully taken into account, results for the most relevant nuclei are provided
and a discussion of the influence of the quark mixing is included. The results
for the Ti nucleus are in good agreement with earlier work by Blanke et al.,
where a degenerate mirror quark sector was assumed. The conclusion is that,
although this particular model reduces the tension with electroweak precision
tests, if the restrictions on the parameter space derived from lepton flavor
violation are taken seriously, the degree of fine tuning necessary to meet
these constraints also disfavors this model.Comment: 26 pages, 7 figures, 4 tables; discussion improved, results
unchanged, one reference added, version to appear in JHE
Little Higgs model effects in
Though the predictions of the Standard Model (SM) are in excellent agreement
with experiments there are still several theoretical problems associated with
the Higgs sector of the SM, where it is widely believed that some ``{\it new
physics}'' will take over at the TeV scale. One beyond the SM theory which
resolves these problems is the Little Higgs (LH) model. In this work we have
investigated the effects of the LH model on \gggg scattering
\cite{Choudhury:2006xa}.Comment: Talk given at LCWS06, Bangalore, 4 pages (style files included
Pair production of the heavy leptons in future high energy linear e^{+}e^{-} colliders
The littlest Higgs model with T-parity predicts the existence of the T-odd
particles, which can only be produced in pair. We consider pair production of
the T-odd leptons in future high energy linear collider ().
Our numerical results show that, as long as the T-odd leptons are not too
heavy, they can be copiously produced and their possible signals might be
detected via the processes in future
experiments.Comment: Discussions added, typos and references correcte
The flavor-changing bottom-strange quark production in the littlest Higgs model with T parity at the ILC
In the littlest Higgs model with T-parity (LHT) the mirror quarks induce the
special flavor structures and some new flavor-changing (FC) couplings which
could greatly enhance the production rates of the FC processes. We in this
paper study some bottom and anti-strange production processes in the LHT model
at the International Linear Collider (ILC), i.e.,
and . The results show that the production
rates of these processes are sizeable for the favorable values of the
parameters. Therefore, it is quite possible to test the LHT model or make some
constrains on the relevant parameters of the LHT through the detection of these
processes at the ILC.Comment: 12 pages, 8 figure
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