Related papers: Rare Z Decays
In these lectures we give, first, the model-independent analysis of the exclusive rare decays B -> K l(bar) l and B_c -> D(D*) l(bar) l with special emphasis on the cascade decay B_c -> D(*)(-> D pi) l(bar) l. We derive a four-fold angular…
Based on the expectation generated by the discovery of new particles by current colliders, we analyze the decay of the Z' boson in the frame of one of the SU(3)L \otimes U(1)N electroweak extensions of the standard model. The main objective…
We present first theoretical predictions for various observables related to the $\bar B_d \to \mu^+ \mu^- e^+ e^-$ decay within the framework of the Standard Model. Our study encompasses the branching ratios, differential distributions, and…
Rare loop-induced decays are sensitive to New Physics in many Standard Model extensions. In this paper we discuss the potential of the LHCb experiment to very rare $\mathrm{B_s} \to \mu^+ \mu^-$ decays, radiative penguin $\mathrm{b \to…
In U(1) extensions of the Minimal Supersymmetric extension of the Standard Model there is a simple mechanism that leads to a heavy Z' boson with a mass which is substantially larger than the supersymmetry breaking scale. This mechanism may…
Rare decays of the $B$ meson are sensitive to new physics effects. Several experimental results on these decays have been difficult to understand within the standard model (SM) though more precise measurements and a better understanding of…
This report summarizes the latest experimental results on radiative and electroweak rare B meson decays. These rare decay processes proceed through the flavor changing neutral current processes, and thus sensitive to the postulated new…
An interesting extension of the Standard Model is based on the electroweak gauge group SU(3)_L x U(1). It requires three generations to cancel anomalies, treats the third generation differently than the first two, and has a rich…
We briefly review the lepton flavor violating Z-decays at GigaZ as a probe of supersymmetry by focusing on $Z \to \ell_i \overline{\ell}_j$ in two representative supersymmetric models: the minimal supersymmetric model without R-parity and…
The experimental information on b --> s l^+ l^- decays has grown enormously during the last couple of years due to BaBar, Belle, CDF and LHCb. Especially, exclusive modes B --> K^(*) l^+ l^-, which have the largest rate and are easily…
We consider the exclusive flavor changing neutral current processes B -> M \nu \bar{\nu} (M= \pi, K, \rho, K^*) in the leptophobic Z^\prime model, in which the charged leptons do not couple to the extra Z^\prime boson. We find that these…
The rare top decay t-> c l+l-, which involves flavor violation, is studied as a possible probe of new physics. This decay is analyzed with the simplest Standard Model extensions with additional gauge symmetry formalism. The considered…
I report on developments in the experimental and phenomenological understanding of the rare decays of mesons containing b and c quarks, especially as they pertain to the understanding of the CKM matrix and the testing of the standard model.…
Rare leptonic and semi-leptonic decays offer an excellent opportunity to test the Standard Model of Particle Physics. These proceedings report on two recent LHCb measurements. The first is an observation of the rare $J/\psi \to…
Minimal extensions of the Standard Model that are motivated by grand unified theories or superstring models with an E_6 symmetry can naturally predict heavy neutrinos of Dirac or Majorana nature. Such heavy neutral leptons violate the de-…
The realization that first- and second-generation Yukawa couplings can be probed by decays of the Higgs boson to a meson in association with a photon has renewed interest in such rare exclusive decays. We present here a detailed study of…
We present a brief overview of rare K decays, emphasizing the different role of Standard Model and possible New Physics contributions in various channels.
The rare decays of mesons are higher order effects in weak interactions. The main contributions to such decay processes are from the Z-penguin, the photonpenguin and the box diagram. At the quark level, these contributions are well known.…
We study the rare $\Lambda_b\to\Lambda\mu^+\mu^-$ decay in the Standard Model and beyond. Beyond the Standard Model we include new vector and axial-vector operators, scalar and pseudo-scalar operators, and tensor operators in the effective…
We discuss the very rare, exclusive hadronic decays of a Z boson into a meson and a photon. The QCD factorization approach allows to organize the decay amplitude as an expansion in powers of $\Lambda_{\rm QCD}/m_Z\,$, where the leading…