Related papers: Rare radiative charm decays within the standard mo…

We present a calculation of the rare decay mode D^0 -> gamma gamma, in which the long distance contributions are expected to be dominant. Using the Heavy Quark Chiral Perturbation Theory Lagrangian with a strong g coupling as recently…

To the leading order, the radiative leptonic decays $B_c \to \gamma \ell \bar \nu$ ($ \ell=e, \mu$) are studied carefully. In the study, a non-relativistic constituent quark model and the effective Lagrangian for the heavy flavour decays…

The experimental decay branching ratios of mesons like $B_s\to \ell\bar \ell$ and $B_d\to \ell\bar \ell$ ($\ell=e$ or $\mu$) do not agree completely with the standard model (SM). Cartan's supersymmetry predicts relation of the coupling of…

Rare charm decays offer the unique possibility to explore flavour-changing neutral-currents in the up-sector within the Standard Model and beyond. Due to the lack of effective methods to reliably describe its low energy dynamics, rare charm…

We compute 10 radiative three-body decays of charged charmed mesons $D^+ \to P^+ P^0 \gamma$ and $D_s \to P^+ P^0 \gamma$, $P=\pi, K$, in leading order QCDF, HH$\chi$PT and the soft photon approximation. We work out decay distributions and…

We study the available data on exclusive leptonic and semileptonic $c\to s\ell^+\nu$ decays within the Standard Model and beyond. Our analysis accounts for theory correlations between the relevant hadronic matrix elements through…

We present a systematic analysis for the rare baryonic exclusive decays of $\Lambda_b\to\Lambda l^+ l^- (l=e,\mu,\tau)$. We study the differential decay rates and the di-lepton forward-backward, lepton polarization and various CP…

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 persistent tensions between inclusive and exclusive determinations of $|V_{cb}|$ and $|V_{ub}|$ weaken the power of theoretically clean rare $K$ and $B$ decays in the search for new physics (NP). We demonstrate how this uncertainty can…

Using the large data sample accumulated by the Belle experiment at KEKB asymmetry energy $e^+e^-$ Collider, we report the preliminary measurements of the branching fractions of the radiative decays $D^0 \rightarrow V\gamma$, where $V$ =…

With heavy quark limit and hierarchy approximation $\lambda_{QCD}\ll m_D\ll m_B$, we analyze the $B\to D^0\bar D^0$ and $B_s\to D^0\bar D^0$ decays, which occur purely via annihilation type diagrams. As a roughly estimation, we calculate…

The problem of possible deviations from the Standard Model is considered in the framework of a variant of dynamical electroweak symmetry breaking. The parameters of the theory are obtained, which describe deviations from SM in $Z\to \bar b…

FCNC processes offer important tools to test the Standard Model (SM), and to search for possible new physics. In this work, we investigate the $s\to d\nu\bar{\nu}$ rare hyperon decays in SM and beyond. We find that in SM the branching…

We study charmless pure annihilation type radiative B decays within the QCD factorization approach. After adding the vertex corrections to the naive factorization approach, we find that the branching ratios of $\bar{B}^0_d\to\phi\gamma$,…

We investigate the physics potential of the annihilation decays $\bar{B}^0_{s,d} \to J/\psi$ $\gamma$ in the Standard Model and beyond. In naive factorization approach, the branching ratios are estimated to be $\mathcal{B}(\bar{B}^0_s \to…

This study examines the rare decay $B \to K_0^*(1430)\,\ell^+ \ell^-$ as a possible probe for new physics beyond the standard model (SM). We first analyze this channel within the SM and then include scalar leptoquark (LQ) contributions. We…

Polarized $\Lambda_b \to \Lambda \gamma$ decays at the Z pole are shown to be well suited for probing a large variety of New Physics effects. A new observable is proposed, the angular asymmetry between the $\Lambda_b$ spin and photon…

Rare decays $\Lambda_b \to \Lambda \gamma$ and $\Lambda_b \to \Lambda l^{+} l^{-}$ (l= e, $\mu$) are examined. We use QCD sum rules to calculate the hadronic matrix elements governing the decays. The $\Lambda$ polarization in the decays is…

Rare $|\Delta c|=|\Delta u|=1$ transitions into dineutrinos are strongly GIM-suppressed and constitute excellent null tests of the standard model. While branching ratios of $D \to P \,\nu \bar \nu$, $D \to P^+ P^- \, \nu \bar \nu$, $P=\pi,…

We describe two recent theoretical calculations of the $B \to K^* \gamma$ decay. The first method is based on an effective lagrangian incorporating chiral symmetry for the light degrees of freedom and the heavy quark spin-flavor symmetries…