Related papers: Constraints on Extended Technicolor Models from B …
Many models of Beyond the Standard Model physics involve heavy colored fermions. We study models where the new fermions have vector interactions and examine the connection between electroweak precision measurements and Higgs production. In…
In usual extended technicolor (ETC) theories based on the group ${\rm{SU}(N_{ETC}})_{ETC}$, the quarks of charge 2/3 and -1/3 and the charged leptons of all generations arise from ETC fermion multiplets transforming according to the…
We examined the rare decays $B\to X_s\ell^+\ell^-$ and $B_s\to\ell^+\ell^-\gamma$ in the minimal supersymmetric model with large $\tan\beta$. Taking into account the gluino-loop and neutralino-loop effects, we found that for a large…
The experimental decay branching ratios of mesons like $B_s\to \ell\bar \ell$ and $B_d\to \ell\bar \ell$ ($\ell=e$ or $\mu$) do not agree completely with the standard model (SM). Cartan's supersymmetry predicts relation of the coupling of…
It is notorious that, contrary to all other precision electroweak data, the forward-backward asymmetry for b quarks $A_{FB}^b$ measured in Z decays at LEP1 is nearly three standard deviations away from the predicted value in the Standard…
We show that the $\eta\gamma Z$ anomaly can be measured by analysing parity-violating effects in the $\eta-->\gamma\mu+\mu-$ decay. In this sense, we find that the longitudinal polarization of the outgoing $\mu^+$ is an appropriate…
We study the forward-backward asymmetries in the decays of $K^+\to\pi^+\ell^+ \ell^-$ ($\ell=e$ and $\mu$) in the presence of scalar or tensor terms. We find that with the scalar (tensor) type interaction the asymmetry can be up to ${\cal…
The HyperCP collaboration has recently reported the observation of three events for the decay Sigma^+ -> p mu^+ mu^-. They have suggested that new physics may be required to understand the implied decay rate and the observed M_{mumu}…
I review the status of the rare decays B_s --> mu+mu- and B_d --> mu+mu-. The latest Standard Model predictions for the corresponding branching ratios are discussed. An overview of additional observables that are accessible in the B_s -->…
The very rare Bd0 --> mu+ mu- decay may be the last chance for New Physics in flavor sector at the LHC, before the 13 TeV run in 2015. Partially motivated by the known tension in sin(2beta/phi_1), enhancement beyond (3-4) x 10^-10 would…
B decays in and beyond the standard model are reviewed. I specifically discuss right-handed B decays, rare B decays, B_c decays, B_s-B_s(bar) mixing, and T violation. (Plenary talk given at the `Workshop on B Physics at Hadron…
The measured rate for D_s -> l nu decays, where l is a muon or tau, is larger than the standard model prediction, which relies on lattice QCD, at the 3.8 sigma level. We discuss how robust the theoretical prediction is, and we show that the…
We revisit the rare decays of the Higgs boson to two different quarks in the Standard Model, which arise at the one-loop level. We perform Taylor series expansions to the complete form factors of the decay amplitudes, according to their…
I discuss recent progress in our understanding of exclusive rare and semileptonic decays. I show the impact of HQET when combined with the predictions in the Large Energy Limit of QCD, focusing first on applications to $B\to…
We study the q^2 dependence of the exclusive decay mode B \to D tau \bar{nu} in type II two Higgs doublet models and show that this mode may be used to put stringent bounds on tan(beta)/m_H. There are currently rather large theoretical…
We study the differential branching ratio, branching ratio and the CP-violating asymmetry for the exclusive $B_{d}->(\eta, \eta^{\prime}) \ell^+ \ell^-$ decays in the standard model. We deduce the $B_{d}->(\eta, \eta^{\prime})$ form factors…
The radiative decay b to s gamma is examined in the Standard Model and in nine classes of models which contain physics beyond the Standard Model. The constraints which may be placed on these models from the recent results of the CLEO…
Physics beyond the Standard Model could be measured indirectly, through its effects on Standard Model observables. One place to look for such effects is in the semileptonic decays of B mesons. In order to constrain the possible role of new…
A detailed analysis on the rare $\tau$ decay {\it via} $\taumue$ and $\taumus$ in the string models with $\e6$ symmetry is reported. It is found that $\Gamma(\taumue)\sim(6-7)\Gamma(\taumus)$ and these rates are in general about 1000 times…
Theoretical predictions for the top quark rare decays are reviewed within and beyond the standard model. Expectations at the CERN Large Hadron Collider are discussed.