Related papers: A General Lower Bound for Radiative B Decay
Top flavour-changing neutral decays are extremely suppressed within the Standard Model (SM) by the GIM mechanism, but can reach observable rates in some of its extensions. We compute the branching ratios for t -> c gamma and t -> c g in…
We report on recent theoretical progress in radiative B decays. We focus on a calculation of logarithmically enhanced QED corrections to the branching ratio and forward-backward asymmetry in the inclusive rare decay anti-B --> X(s) l+ l-,…
We report results of a search for the rare radiative decay B0 -> D*0 gamma. Using 9.7 million BB meson pairs collected with the CLEO detector at the Cornell Electron Storage Ring, we limit Br(B0->D*0 gamma) < 5.0 * 10^-5 at 90% CL. This…
The standard model prediction for the $B\to X_{s,d}\gamma$ decay amplitude with a right-handed photon is believed to be tiny, suppressed by $m_{s,d}/m_b$, compared to the amplitude with a left-handed photon. We show that this suppression is…
We investigate the bounds on axionlike states from flavor-changing neutral current b->s decays, assuming the axion couples to the standard model through mixing with the Higgs sector. Such GeV-scale axions have received renewed attention in…
It is argued that the topcolor models recently proposed by Hill [1] may face significant constraints from flavor-changing neutral current processes (such as $B-\bar{B}$ mixing) unless the mixing angles between down-type quarks are small.…
We study the weak radiative decays of ${\bf B}_b \to {\bf B}_n \gamma$ with ${\bf B}_{b(n)} $ the anti-triplet-bottom (octet) baryons in the light front quark model. We obtain that ${\cal B}(\Lambda_b \to \Lambda \gamma)= (7.1 \pm 0.3…
A bound on the angle gamma of the unitarity triangle is derived using experimental information on the CP-averaged branching ratios for the rare decays B^+- -> pi^+- K^0 and B^+- -> pi^0 K^+-. The theoretical description is cleaner than the…
We study the $B$ meson radiative decay $B \to X_s \gamma$ in the vector quark model. Deviation from the Standard Model arises from the non-unitarity of the charged current KM matrix and related new FCNC interactions. We establish the…
Recent results in radiative B decays from the Belle and BaBar collaborations are discussed. New measurements of the decay rate and CP asymmetries in b -> s gamma and b -> d gamma decays are presented, together with measurements of the…
We report a fully inclusive measurement of the flavor changing neutral current decay $B\to X_s\gamma$ in the energy range $1.7 \GeV\le E^\mathrm{c.m.s}_\gamma\le 2.8 \GeV$, covering 97% of the total spectrum, where c.m.s is the center of…
We present an analysis on the exclusive rare radiative decay modes Sigma_b->Sigma gamma and Xi_b->Xi gamma. The transition form factors which parameterize these processes are calculated using QCD light-cone sum rules. The decay widths we…
We reanalyse the recent version of the chiral model of weak radiative hyperon decays, proposed by Borasoy and Holstein. It is shown that predictions of the analysed model are significantly changed when one accepts the usual classification…
A plethora of ultraviolet completions of the Standard Model have extra U(1) gauge symmetries. In general, the associated massive $Z^\prime$ gauge boson can mediate flavor-changing neutral current processes at tree level. We consider a…
The flavour changing decays of the top quark are severely suppressed in the Standard Model by virtue of the Glashow-Iliopoulos-Maiani mechanism. Many beyond Standard Model extensions predict the decay rates at a level that is observable in…
We present an overview of the recent neutral current $B$ decays focusing on the deviations with respect to the Standard Model predictions that are observed in $b \to s \ell^+\ell^-$ transitions, and discuss their implications for new…
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…
An exact calculation of the Higgs boson decays $H\to q_i q_j$ mediated by flavor changing neutral currents is presented in the context of the Standard Model. Using up-to-date experimental data, branching ratios of the order of $10^{-7}$,…
Recent BABAR and Belle results on rare B decays involving photons or lepton pairs are reviewed. New preliminary limits from both experiments for B-->rho gamma and B-->omega gamma, and from BABAR for B --> K nu nu and B --> tau nu are…
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…