2 research outputs found
Rare B decays and Tevatron top-pair asymmetry
The recent Tevatron result on the top quark forward-backward asymmetry, which
deviates from its standard model prediction by 3.4, has prompted many
authors to build new models to account for this anomaly. Among the various
proposals, we find that those mechanisms which produce via - or
-channel can have a strong correlation to the rare B decays. We demonstrate
this link by studying a model with a new charged gauge boson, . In terms of
the current measurements on decays, we conclude that the branching
ratio for is affected most by the new effects.
Furthermore, using the world average branching ratio for the exclusive B decays
at level, we discuss the allowed values for the new parameters.
Finally, we point out that the influence of the new physics effects on the
direct CP asymmetry in B decays is insignificant.Comment: 15 page, 6 figures, typos corrected and references added, final
version to appear journa
Phenomenology of a light gluon resonance in top-physics at Tevatron and LHC
We present a phenomenological analysis of the recent Tevatron results on the
forward-backward asymmetry and invariant-mass spectrum assuming a
new contribution from an s-channel gluon resonance with a mass in the range
from 700 to 2500 GeV. In contrast to most of the previous works, this analysis
shows that for masses below ~1 TeV resonant New Physics could accommodate the
experimental data. In general, we find that axial-like couplings are preferred
for light and top quark couplings, and that only top quark couples strongly to
New Physics. We find that composite model scenarios arise naturally from only
phenomenological analyses of the experimental results. We show that our results
are compatible with recent LHC limits in dijet and production, and
find some tension for large resonance mass ~2.5 TeV. We indicate as best
observables for discriminating a relatively light new gluon a better resolution
in CDF forward-backward asymmetry, as well as the charge asymmetry
and invariant-mass spectrum at the LHC.Comment: 22 pages with 5 figure