Related papers: b -> s Decays in a model with Z-mediated flavor ch…
Searches for flavor changing neutral currents in top production and decay using data collected by the Compact Muon Solenoid (CMS) experiment at $\sqrt{s}$ = 7 and 8 TeV are presented, corresponding to an integrated luminosity of around 5…
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…
We discuss two models with 1 extra CP phase in $b\leftrightarrow s$ transition. The CP phase $\arg (V_{t^\prime s}V_{t^\prime b})$ with fourth generations, previously ignored, could impact on $b\to s\ell^+\ell^-$, $\Delta m_{B_s}$ and…
Rare radiative decays based on b->s+gamma transitions are among the most prominent examples of flavor-changing neutral current processes. They benefit from good theoretical control and experimental accessibility, large sensitivity to…
The flavor-changing neutral current semileptonic decays of $B$ mesons provide an excellent platform for indirectly probing New Physics (NP) beyond the Standard Model (SM). Recent measurements of lepton flavor universality (LFU) ratios such…
We study the contribution of charged Higgs boson to the rare decay of the top quark t->q+WZ (q=d,s,b) in models with Higgs sector that includes doublets and triplets. Higgs doublets are needed to couple charged Higgs with quarks, whereas…
We have systematically investigated the semi-inclusive B decays $B\to MX$, which are manifestations of the quark decay $b \to Mq$, within a framework inspired by QCD-improved factorization. These decays are theoretically clean and have…
We try to understand the polarization puzzle in $B\to \phi K^*$ decays with a simple Higgs model associated with flavor changing neutral current at tree level. The new interactions can effectively reduce the longitudinal polarization…
Models with a non-universal Z' exhibit in general flavor changing neutral currents (FCNC) at tree-level. When the Z' couplings favor the third generation, flavor changing transitions of the form Z'tc and Z'tu could be large enough to be…
The simplest extension of the SM that generally introduces new sources of flavour and CP violation as well as right-handed currents is the addition of a U(1) gauge symmetry to the SM gauge group. If the corresponding heavy gauge boson Z'…
We address the recent anomalies in semi-leptonic $B$-meson decays using a model of fermion masses based on the $U(2)$ flavor symmetry. The new contributions to $b \to s \ell \ell$ transitions arise due to a tree-level exchange of a…
We present an effective Lagrangian formalism for the calculation of flavour changing neutral and charged scalar currents in weak decays including $SU(2)\times U(1)$ symmetry breaking effects and the effects of the electroweak couplings…
The charmed B decays, $B\to DP, ~D^*P$ and $DV$, are re-analyzed using the latest experimental data, where $P$ and $V$ denote the pseudoscalar meson and vector meson, respectively. We perform global fits under the assumption of flavor SU(3)…
Time-dependent measurements of the decays B_s^0(t)-->\phi K_s and B_d^0(t) --> K^0 \bar{K}^0 can be used to compare the weak phases of B_d^0-\bar{B}_d^0 mixing and the t-quark contribution to the b->d penguin. Since these two phases are…
We investigate the possibility of having sizable effects from flavor changing neutral currents at the tree level in a particular class of Two Higgs Doublet Models. Constraints from existing experimental information are discussed. Some…
The D0 Collaboration reported a 3.2sigma deviation from the standard model prediction in the like-sign dimuon asymmetry. Assuming that new physics contributes only to B_{d,s} mixing, we show that the data can be analyzed without using the…
In models where an additional SU(2)-doublet that does not have couplings to fermions participates in electroweak symmetry breaking, the properties of the Higgs boson are changed. At tree level, in the neighborhood of the SM-like range of…
The flavor-changing neutral current decays of heavy bottom quark, alongside the flavor-changing charged current processes mediated by $b \to (c, u)$ in semileptonic $B$ decays are emerged as powerful tools for exploring physics beyond the…
Recent measurements of semileptonic B-meson decays seemingly imply violations of lepton flavor universality beyond the Standard Model predictions. With three-level explanations based on extended Higgs sectors being strongly challenged by…
In extended Higgs models, a discrete symmetry is needed in the quark sector to avoid tree-level flavor-changing neutral currents. However, this is not necessary the case in the lepton sector. We consider a model in which one Higgs couples…