Related papers: Analysis of ${\Lambda}_b\rightarrow{\Lambda}l^+ l^…
We study the differential decay rate for the rare $\Lambda_b \to \Lambda (\to N \pi)\ell^+\ell^-$ transition, including a determination of the complete angular distribution, assuming unpolarized $\Lambda_b$ baryons. On the basis of a…
We study the semileptonic decays of $\Lambda_c^+ \to \Lambda(n)\ell^+ \nu_{\ell}$ in two relativistic dynamical approaches of the light-front constituent quark model (LFCQM) and MIT bag model (MBM). By considering the Fermi statistic…
We propose two different and complementary observables for singling out possible signals of physics beyond the standard model in the semi-leptonic decays $\Lambda_b \to \Lambda_c \ell{\bar \nu}_{\ell}$, both with the $\tau$ lepton and with…
Leptophobic Z' gauge bosons can appear in models with an E_6 gauge symmetry. We show that flavour-changing neutral currents can be generated in some of these models due to the mixing of the ordinary d_R, s_R and b_R quark fields with the…
Rare flavour-changing neutral-current transitions of the type $s \to d \ell^+\ell^-(\nu\bar\nu)$ and $b \to s \ell^+\ell^-(\nu\bar\nu)$ are analysed in supersymmetric extensions of the Standard Model with generic flavour couplings. It is…
Using the general, model independent form of the effective Hamiltonian, the general expressions of the longitudinal, normal and transversal polarization asymmetries for (l^-) and (l^+) and combinations of them for the exclusive (B -> K l^+…
We study the dilepton forward-backward and the longitudinal, normal and transverse lepton polarization asymmetries in the heavy baryon decays of $\Lambda_b\to\Lambda l^+l^-$. We show that the asymmetries have a less dependence on the…
The Belle-II experiment has recently reported the first measurement of $B^+ \to K^+ \nu\bar{\nu}$ decay which exceeds the Standard Model prediction by approximately 2.7$\sigma$. The deviation may indicate the presence of new physics beyond…
New neutral heavy gauge bosons ($Z^\prime$) are predicted within many extensions of the Standard Model. While in case they couple to quarks the LHC bounds are very stringent, leptophilic $Z^\prime$ bosons (even with sizable couplings) can…
Motivated by the recent measurement on ${\cal B}(\bar{B}_s\to \phi \mu^+\mu^-)$ by CDF collaboration, we study the effects of a family non-universal $Z^{\prime}$ boson on rare semileptonic $\bar{B}_s \to \phi\mu^+\mu^-$ decay. In our…
We present an overview of rare K, D and B decays. Particular attention is devoted to those flavour-changing neutral-current processes of K and B mesons that offer the possibility of new significant tests of the Standard Model. The…
In a covariant quark-diquark model, we investigate the rare decay of $\Lambda_b \rightarrow n l^+ l^-$ and $\Lambda_b \rightarrow n \gamma$ in the Bethe-Salpeter equation approach. In this model the baryons are treated as bound states of a…
A model-independent analysis for the exclusive, rare B -> pi^+ pi^- l^+ l^- decay is presented. The dependence of the various physically measurable asymmetries and CP violating asymmetry on the new Wilson coefficients is studied in detail.…
We present a detailed theoretical analysis of very rare, exclusive hadronic decays of the electroweak gauge bosons V=W, Z from first principles of QCD. Our main focus is on the radiative decays V->M+gamma, in which M is a pseudoscalar or…
b to s transitions are flavour-changing neutral current (FCNC) processes that play an important role in the search for physics beyond the Standard Model (SM). Contributions from virtual particles in the loop are predicted to deviate…
We present a general analysis of B_{s,d}-> l^+ l^- and K_L -> l^+ l^- decays in supersymmetric models with non-minimal sources of flavour mixing. In spite of the existing constraints on off-diagonal squark mass terms, these modes could…
Rare radiative, leptonic and semileptonic B meson decays are valuable probes of physics beyond the Standard Model. This talk reviews the sensitivity to new physics of observables related to two rare B decays to be measured in the near…
The weak decays of doubly heavy $\Xi_{QQ}$ baryon induced by flavor changing $b \to d$ and $ c \to u$ flavor changing neutral current within the light cone sum rules are studied. Using the parallel components of the light cone distribution…
In this talk an analysis of the rare exclusive $B$ decays $B\to K\nu\bar\nu$ and $B\to K^{*}\nu\bar\nu$ within and beyond the Standard Model is presented. Combining new form factor determinations from lattice QCD with light-cone sum rule…
Flavour changing neutral current (FCNC) transitions $c\to u\gamma$ and $c\to ul^+l^-$ are very rare in the standard model and present an interesting probe for the physics beyond it. We study long distance contamination to these short…