相关论文: Unparticle effects in rare (t -> c g g) decay
Inspired by the recent Georgi's unparticle proposal, we study the flavor structures of the standard model (SM) particles when they couple to unparticles. At a very high energy scale, we introduce $\BZ$ charges for the SM particles, which…
We study the impact of unparticle physics to the chromomagnetic dipole moment (CMDM) of the top quark. We compute the effect induced by unparticle operators of scalar and vector nature coupled to fermions on the CMDM. We find that this…
In this work, we explore the flavour changing decays $H_i \to b s$ in a general supersymmetric scenario. In these models, the flavour changing decays arise at loop-level but, originating from a dimension-four operator, do not decouple and…
We recalculate the branching ratios for $t\to cV$ ($V=g,\gamma,Z$) induced by SUSY FCNC couplings within the general unconstrained MSSM framework using mass eigenstate approach. Our results show that the branching ratios for these decays…
We address Standard Model predictions for flavor-changing radiative transitions of the pseudoscalar charm mesons. Short-distance contributions in $D$ radiative transitions are contrasted with those in B decays. A full analysis is presented…
We study the CP asymmetries of the rare top-quark decays $t \to c \gamma$ and $t \to cg$ in the aligned two-Higgs-doublet model (A2HDM), which is generically characterized by new sources of CP violation beyond the Standard Model (SM).…
We investigate the effects of flavor dependence on the rare weak decays of $ B_c^{*} $ and $B_s^{*}$ mesons to psuedoscalar and vector mesons in the final state. We use the Bauer-Stech-Wirbel model framework to calculate the flavor…
Deviations from the standard model prediction have been observed in several leptonic and semileptonic $B$ meson decays to $\tau\nu$ final states mediated via $b \to u$ and $b \to c$ charged current interactions. The measured value of ratio…
We examine the decays $t\rightarrow c\gamma$ and $c Z^0$ in the Standard Model with an extra scalar doublet and no discrete symmetry preventing tree-level flavour changing neutral currents. The Yukawa couplings of the new scalars are…
The tau is the only known lepton that can decay hadronically. From this class of decays, high precision measurements of several quantities can be extracted: the CKM matrix element $V_{us}$, the mass of the strange quark, etc. Also, as a…
A tree-level flavor changing neutral current in the up-like quark sector appears in one of the variations of the Littlest Higgs model. We investigate the effects of this coupling in the D+ -> pi+ l+ l- and D0 -> rho0 l+ l- decays, which are…
Recent advances in the calculation of the $b\to s\gamma$ decay branching ratio are presented in the context of supersymmetric theories. Theoretical accuracy increased by inclusion of the next-to-leading order QCD corrections makes it…
We study the contribution of the tensor unparticle mediation to the branching ratios of the radiative lepton flavor violating decays and predict a restriction region for free parameters of the scenario by using experimental upper limits. We…
In the standard model (SM), we re-investigate the rare decay $B\to \phi\pi$, which has been viewed as an ideal probe to detect the new physics signals beyond the SM. Contributions in the naive factorization method, the radiative…
This dissertation investigates the flavor mixing effects in supersymmetric models on electroweak precision observables, Higgs boson mass predictions, B-physics observables, quark flavor violating Higgs decays, lepton flavor violating…
We combine recent progress in measuring the branching ratio of the decay B->X_d gamma$ with the discovery that hadronic uncertainties in the CP-averaged branching ratio drop out to a large extent. Implications of these improvements on the…
The recently observed mass difference of the $D^0-\overline{D^0}$ mixing is used to predict the branching ratios of the rare top quark decays $t\to u\gamma$ and $t\to ug$ in a model independent way using the effective Lagrangian approach.…
The flavor structure in unified theory is probed with superparticle mass spectrum observed in future particle experiments. A key ingredient is the generation dependence of scalar mass non-degeneracy. The observed non-degeneracy in…
The coupling of an unparticle operator O_U to Standard Model particles opens up the possibility of unparticle decays into standard model fields. We study this issue by analyzing the pole structure (and spectral function) of the unparticle…
The reactions e+e- -> t bar-c nu_e bar-nu_e, t bar-c e+ e- are very sensitive probes of the flavor-changing-scalar couplings which can occur in a model with one extra Higgs doublet. At the Next Linear Collider, with a center of mass energy…