201 research outputs found
The Effects of Non-Local Interactions in Rare B Decays, B -> X_s l^+l^-
The effects of non-local interactions in rare B decays, \Bsll, are
investigated. We show the correlation between the branching ratio and the
forward-backward asymmetry via two coefficients of the non-local interactions.
This will certainly help us find any deviations from the standard model through
the non-local interactions.Comment: 16 pages, 5 figures, LaTeX, Accepted for IJMP
Longitudinal polarization asymmetry of leptons in the pure leptonic B decays
Longitudinal lepton polarization asymmetry in B_q -> l l (q = d, s$ and l =
e, mu, tau) decays is investigated. The analysis is done in a general manner by
using the effective operators approach. It is shown that the longitudinal
lepton polarization asymmetry would provide a direct search for the scalar and
pseudoscalar type interactions, which are induced in all variants of
Higgs-doublet models.Comment: 7 page
CP Asymmetry of in Low Invariant Mass Region
I analyzed the CP asymmetry of based on model-independent
analysis which includes twelve independent four Fermi operators. The CP
asymmetry is suppressed in the Standard Model, however, if some new physics
make it much larger, the present or the next generation B factories may catch
the CP violation in this decay mode. In this paper, we studied the correlation
of the asymmetry and the branching ratio, and then we will find only a type of
interactions can be enlarge the asymmetry. Therefore, in comparison with
experiments, we have possibility that we can constrain models beyond the
standard model.Comment: 12 pages, 5 figures, LaTeX, Accepted for Physical Review
Possible Supersymmetric Effects on Angular Distributions in Decays
We investigate the angular distributions of the rare B decay, , in general supersymmetric extensions of the standard
model. We consider the new physics contributions from the operators
in small invariant mass region of lepton pair. We show that the
azimuthal angle distribution of the decay can tell us the new physics effects
clearly from the behavior of the distribution, even if new physics does not
change the decay rate substantially from the standard model prediction
New Physics Effects in Decays
We present a model-independent analysis of rare B decays, . The effect of possible new physics is written in terms of dimension-6
four-fermi interactions. The lepton number violating scalar- and tensor-type
interactions are included, and they induce decays. We show systematically how the branching ratios and
missing mass-squared spectrum depend on the coefficients of the four-fermi
interactions.Comment: 20 pages with 7 figure
A Systematic Analysis of the Lepton Polarization Asymmetries in the Rare B Decay, B -> X_s\tau^+\tau^-
The most general model-independent analysis of the lepton polarization
asymmetries in the rare B decay, \Bstt, is presented. We present the
longitudinal, normal and transverse polarization asymmetries for the
and , and combinations of them, as functions of the Wilson coefficients
of twelve independent four-Fermi interactions, ten of them local and two
nonlocal. These procedures will tell us which type of operators contributes to
the process. And it will be very useful to pin down new physics systematically,
once we have the experimental data with high statistics and a deviation from
the Standard Model is found.Comment: 24 pages, 8 figures, LaTe
Lepton Polarization and Forward-Backward Asymmetries in b -> s tau+ tau-
We study the spin polarizations of both tau leptons in the decay b -> s tau+
tau-. In addition to the polarization asymmetries involving a single tau, we
construct asymmetries for the case where both polarizations are simultaneously
measured. We also study forward-backward asymmetries with polarized tau's. We
find that a large number of asymmetries are predicted to be large, >~ 10%. This
permits the measurement of all Wilson coefficients and the b-quark mass, thus
allowing the standard model (SM) to be exhaustively tested. Furthermore, there
are many unique signals for the presence of new physics. For example,
asymmetries involving triple-product correlations are predicted to be tiny
within the SM, O(10^{-2}). Their observation would be a clear signal of new
physics.Comment: 21 pages, LaTeX, 4 figures (included). Paper somewhat reorganized,
references greatly expanded, conclusions unchange
Lepton Polarization Asymmetry in B\to\ell^{+}\ell^{-} decay Beyond the Standard Model
The lepton polarization asymmetry in the B\to\ell^{+}\ell^{-} decay, when one
of the leptons is polarized, is investigated using the most general form of the
effective Hamiltonian. The sensitivity of the asymmetry to the new Wilson
coefficients is studied.Moreover, correlations between the lepton polarization
asymmetry and the branching ratio is studied. It is observed that, there are
not exist such regions of new Wilson coefficients, which the value of branching
ratio coincides with SM result while the lepton polarization does not, i.e new
physics effects can be established by studying lepton polarization only.Comment: 9 pages,4 figure
Exclusive semileptonic rare decays K,K^*) \ell^+ \ell^- in supersymmetric theories
The invariant mass spectrum, forward-backward asymmetry, and lepton
polarizations of the exclusive processes are analyzed under supersymmetric context. Special attention is paid to
the effects of neutral Higgs bosons (NHBs). Our analysis shows that the
branching ratio of the process \bkm can be quite largely modified by the
effects of neutral Higgs bosons and the forward-backward asymmetry would not
vanish. For the process \bksm, the lepton transverse polarization is quite
sensitive to the effects of NHBs, while the invariant mass spectrum,
forward-backward asymmetry, and lepton longitudinal polarization are not. For
both \bkt and \bkst, the effects of NHBs are quite significant. The partial
decay widths of these processes are also analyzed, and our analysis manifest
that even taking into account the theoretical uncertainties in calculating weak
form factors, the effects of NHBs could make SUSY shown up.Comment: Several references are added, typo are correcte
General analysis of the rare Bc->D^*_s l^+ l^- decay beyond the standard model
The general analysis of the rare Bc->D^*_s l^+ l^- decay is presented by
using the most general, model independent effective Hamiltonian. The
dependencies of the branching ratios, longitudinal, normal and transversal
polarization asymmetries for l^- and the combined asymmetries for l^- and l^+
on the new Wilson coefficients are investigated. Our analysis shows that the
lepton polarization asymmetries are very sensitive to the scalar and tensor
type interactions, which will be very useful in looking for new physics beyond
the standard model.Comment: 27 Pages, 14 Figure
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