Related papers: Rare B decays in the flip SU(5) Model
A colored weak singlet scalar state with hypercharge 4/3 is one of the possible candidates for the explanation of the unexpectedly large forward-backward asymmetry in $t \bar t$ production as measured by the CDF and D0 experiments. We…
B --> rho l nu decay is analyzed in the effective theory of heavy quark with infinite mass limit. The matrix element relevant to the heavy to light vector meson semileptonic decays is parametrized by a set of four heavy flavor-spin…
We study possible new physics contributions in $B\to\pi\tau\bar\nu $ and $B\to\tau\bar\nu$ employing the model-independent effective Lagrangian that describes the quark-level transition $b \to u \tau\nu$ at low energies. The decay rate of…
We investigate the discovery prospects of a singly produced vector-like bottom quark in the Type-II Two-Higgs-Doublet Model extended by an $SU(2)_L$ vector-like $(T,B)$ doublet. We focus on the non-standard decay chain $B \to \phi b$,…
We study some rare decays of $B_s$ meson governed by the quark level transitions $ b \to s$, in the fourth generation model popularly known as SM4. Recently it has been shown that SM4, which is a simple extension of the SM3, can…
A comparative study of the exclusive rare $B_{c}\rightarrow D_{s}^{\ast}\ell^{+}\ell^{-}$ ($\ell=\mu, \tau$) decays has been made in the minimal supersymmetric models (MSSM) and the SUSY SO(10) GUT models. In this context, various physical…
We study inclusive semileptonic $\bar{B}\to X_c \ell \bar{\nu}$ decays ($\ell = e,\mu$) in the presence of generic physics Beyond the Standard Model (BSM) that is heavy compared to the $b$-quark mass. Its effect is encoded in the Wilson…
In this talk, I present a new framework to understand the long-standing fermion mass hierarchy puzzle. We extend the Standard Model gauge symmetry by an extra local U(1)_S symmetry, broken spontaneously at the electroweak scale. All the SM…
Vector-like quarks are introduced in various new physics models beyond the standard model (SM) at the TeV scale. We especially consider the case that the quark is singlet (triplet) under the SU(2)$_L$ (SU(3)$_c$) gauge group and couples…
New vectorlike quarks have been proposed in many scenarios of new physics beyond the Standard Model, which address the hierarchy problem and may be potentially discovered at the Large Hadron Collider~(LHC). Based on a model-independent…
We investigate the phenomenology of light GeV-scale fermionic dark matter in $U(1)_{L_\mu - L_{\tau}}$ gauge extension of the Standard Model. Heavy neutral fermions alongside with a $S_1(\overline{3}$,$1$,$1/3$) scalar leptoquark and an…
As described previously, in SU(5) gauge theory with massless left-handed $ {\bf 5 \oplus 15 \oplus 40 \oplus 45^*}$ fermions \{QUD\}, an S-Matrix is produced by infra-red anomaly dynamics that might provide an extraordinarily economic…
We investigate the decays of the excited $(b\bar q)$ mesons as probes of the short-distance structure of the weak $\Delta B=1$ transitions. These states are unstable under the electromagnetic or strong interactions although their widths are…
In this paper, we investigate the tree-dominated $\bar{B}^*_{u,d,s,c} \to V \ell^- \bar{\nu}_\ell$ ($V=D^*_{u,d}\,,D^*_s\,,J/\psi$ and $\ell=e\,,\mu\,,\tau$) decays in the Standard Model with the relevant form factors obtained in the…
The exclusive rare decay $B \ra K^\ast \gamma$ takes place in a region of maximum recoil, $q^{2}=0$, posing a problem for nonrelativistic quark models which are usually thought to be most reliable at zero recoil. The Bauer--Stech--Wirbel…
We show that, within the framework of $SU(5)$ Grand Unified Theories (GUTs), multiple vector-like families at the GUT scale which transform under a gauged $U(1)'$ (under which the three chiral families are neutral) can result in a single…
The significant heavy threshold effect is found in the supersymmetric SU(5) model with two adjoint scalars, one of which is interpreted as a massive string mode decoupled from the lower-energy particle spectra. This threshold related with…
Recent anomalies in $B\to K^{(*)}\ell\ell$ meson decays are consistent with exchange of a heavy $Z'$ vector boson. Here we try to connect such new physics to understanding the origin of flavor, by gauging generation number. Phenomenological…
We explore the phenomenology of models containing one Vector-Like Quark (VLQ), $t'$, which can decay into the Standard Model (SM) top quark, $t$, and a new spin-0 neutral boson, $S$, the latter being either a scalar or pseudoscalar state.…
In this paper we investigate the next-to-leading power contribution to the $B_s \to \gamma\gamma$ and $B_s \to \gamma\ell\bar{\ell}$ decays from the strange quark mass effect with the dispersion approach which is QCD inspired and more…