Related papers: $B \to X_s \mu^+ \mu^-$ in Technicolor with Scalar…
The $B\to a_1 \ell^+ \ell^-$ decays occur by the electroweak penguin and box diagrams which can be performed through the flavor changing neutral current (FCNC). We calculate the form factors of the FCNC $B \to a_1$ transitions in the…
We perform a complete and detailed analysis of the flavor changing neutral current rare top quark decays t-> cl+l- and t->c nu_i bar nu_i at one-loop level in the Standard Model, Two Higgs Doublet Models (I and II) and in MSSM. The…
Applying the effective Lagrangian method, we study the Flavor Changing Neutral Current $b\to s\gamma$ within the minimal supersymmetric extension of the standard model where baryon and lepton numbers are local gauge symmetries. Constraints…
We present a search for the lepton flavor violating decay B+ --> K+ tau-/+ mu+/- using 383 million B Bbar events collected by the BABAR experiment. The branching fraction for this decay can be substantially enhanced in new physics models.…
We discuss how LHC di-muon data collected to study $B_q \to \mu\mu$ can be used to constrain light particles with flavour-violating couplings to $b$-quarks. Focussing on the case of a flavoured QCD axion, $a$, we compute the decay rates for…
For a model with a fourth family of quarks, new sources of flavor changing neutral currents are identified by confronting the unitary 4x4 quark mixing matrix with the experimental measured values of the familiar 3x3 quark mixing matrix. By…
$B$ meson rare decays play a crucial role in exploring new physics beyond the standard model. In this study, we explore the rare decay process $B_s^0 \rightarrow \mu^+ \mu^-$ in a flavor violating extension of the Minimal Supersymmetric…
Results on $B \to \mu^+ \mu^-$ decays with the CMS experiment are reported, using 61 fb$^{-1}$ of data recorded during LHC Run 1 and 2016. With an improved muon identification algorithm and refined unbinned maximum likelihood fitting…
We search for the rare flavor-changing neutral current process $B^{+}\rightarrow K^{+}\tau^{+}\tau^{-}$ using data from the BABAR experiment. The data sample, collected at the center-of-mass energy of the $\Upsilon{(4S)}$ resonance,…
We report on the search for $B^0_s\to\mu^+\mu^-$, $B^0_d\to\mu^+\mu^-$ decays and $b\to s \mu^+\mu^-$ transitions in exclusive decays of B mesons using the CDF II detector at the Fermilab Tevatron Collider. Using 2 fb$^{-1}$ of Run II data…
We study those dimension 6 effective operators which generate flavor-changing quark-gluon transitions of the third generation quarks, with t -> g + u(c) and b -> g + d(s), and which could be of interest for LHC experiments. We analyze the…
We demonstrate that flavour-changing neutral currents in the top sector, mediated by leptophilic scalars at the electroweak scale, can easily arise in scenarios of new physics, and in particular in composite Higgs models. We moreover show…
We present a search for the decay $B^{+} \to \tau^{+} \nu_{\tau}$ using 288 fb-1 of data collected at the $\Upsilon(4S)$ resonance with the BaBar detector at the SLAC PEP-II $B$-Factory. A sample of events with one reconstructed…
In this paper, we study the light scalar and pseudoscalar invisible particles in the flavor changing neutral current processes of the $B_c$ meson. Effective operators are introduced to describe the couplings between quarks and light…
In supersymmetric grand-unified models, the lepton mixing matrix can possibly affect flavor-changing transitions in the quark sector. We present a detailed analysis of a model proposed by Chang, Masiero and Murayama, in which the…
We propose the $B_c\to B_u^*\gamma$ decay as the most suitable probe for the flavour changing neutral transition $c\to u\gamma$. We estimate the short and long distance contributions to this decay within the standard model and we find them…
In recent times, several discrepancies at the level of $(2-3)\sigma$ have been observed in the decay processes mediated by flavour changing neutral current (FCNC) transitions $b \to s \ell^+ \ell^-$, which may be considered as the…
Quark and lepton flavor signals are studied in four supersymmetric models, namely the minimal supergravity model, the minimal supersymmetric standard model with right-handed neutrinos, SU(5) supersymmetric grand unified theory with…
We study the decays of $B_{s,d} \to l^+ l^- \gamma (l=e, \mu,\tau)$ within the light-front model. We calculate the tensor type form factors and use these form factors to evaluate the decay branching ratios. We find that, in the standard…
Models beyond the Standard Model with extra scalars have been highly motivated by the recent discovery of a Higgs boson. The Two Higgs Doublet Model Type III considers the most general case for the scalar potential, allowing mixing between…