相关论文: Two Photon Contribution to Polarization in $K^+ \r…
The long-distance contribution via the two-photon intermediate state to the forward-backward asymmetries in decays K+ --> pi+ l+ l- (l=e and mu) has been studied within the standard model. In order to evaluate the dispersive part of the K+…
We revisit the calculation of the long-distance contribution to the muon-polarization asymmetry \Delta_{LR}, which arises, in K^+\to\pi^+\mu^+\mu^-, from the two-photon intermediate state. The parity-violating amplitude of this process,…
We reexamine, update and extend a suggestion we made fifteen years ago for measuring the photon polarization in $b \to s\gamma$ by observing in $B \to K\pi\pi\gamma$ an asymmetry of the photon with respect to the $K\pi\pi$ plane.…
The photon polarization in $D_{(s)} \to K_1 (\to K\pi\pi) \gamma$ decays can be extracted from an up-down asymmetry in the $K \pi \pi$ system, along the lines of the method known to $B \to K_1 (\to K\pi\pi) \gamma$ decays. Charm physics is…
We calculate the transverse muon polarization in the decay $K^{\pm}\to\pi^0\mu^{\pm}\nu$ induced by the electromagnetic two-photon final-state interaction. For the central part of the Dalitz plot the typical value of this polarization is…
The effect of anomalous right-handed top couplings on the photon polarization in $B\to K_{\rm res}\gamma$ is investigated. It is recently reported that the photon polarization can be measured through the up-down asymmetry of the photon…
The rare three body decay of a Higgs boson to a lepton-anti lepton pair and a photon has begun to attract attention, after the first evidence for the $H\to Z\gamma$ at CMS and ATLAS, which is a sub process of $H \to \ell^+ \ell^- \gamma$ .…
We present an analysis of the Beam-Target double polarization asymmetry for the photoproduction of $\Theta^+$ in $\gamma n\to \Theta^+ K^-$. We show that this quantity can serve as a filter for the determination of the $\Theta^+$'s…
The two-pion contribution to hadronic vacuum polarization can be extracted from tau decay data when isospin violating and radiative corrections are taken into account. When the dominant corrections are applied to the photon-inclusive decay…
We estimate two-photon exchange contribution to the process $e^+ +e^- \to p + \bar{p}$. The two-photon exchange corrections to double spin polarization observables and form factors in the time-like region are calculated. The corrections are…
Transverse muon polarization in the $K^+ \rightarrow \mu^+ \nu \gamma$ decay is calculated in the model with scalar and pseudo scalar four-Fermi interactions. Combined with a similar calculation in the $K^+ \rightarrow \mu^+ \nu \pi^0$…
Double polarized forward-backward asymmetries in $B\rightarrow K_{1}(1270,1400)\ell^{+}\ell^{-}$ with $\ell=\mu , \tau$ decays are studied, using most general non-standard local four-fermi interactions, where the mass eigenstates…
We systematically compute and discuss meson and muon polarized radiative decays. Doubly differential distributions in terms of momenta and helicities of the final lepton and photon are explicitly computed. The undergoing dynamics giving…
Polarization properties of the photons emitted in the two-photon decay of hydrogen-like ions are studied within the framework of the density matrix and second-order perturbation theory. In particular, we derive the polarization correlation…
We present a theoretical framework within which both the real and imaginary parts of the complex, two-photon exchange amplitude contributing to $K_L\rightarrow\mu^+\mu^-$ decay can be calculated using lattice QCD. The real part of this…
The origin of the large CP-odd and T-odd asymmetry observed in the decay K_L -> pi^+ pi^- e^+ e^- is traced to the polarization properties of the photon in the decay K_L -> pi^+ pi^- gamma. The Stokes vector of the photon S = (S_1, S_2,…
We have examined the physics and the experimental feasibility of studying various kaon decay processes in which the polarization of a muon in the final state is measured. Valuable information on CP violation, the quark mixing (CKM) matrix,…
We re-examine the possibility to measure the photon polarization in $B \to K^*\gamma$ decays, via decays in which the photon subsequently undergoes nuclear conversion to a lepton pair. We obtain compact expressions for the full…
Based on analyticity, unitarity, and Lorentz invariance the contribution from hadronic vacuum polarization to the anomalous magnetic moment of the muon is directly related to the cross section of e^+e^- --> hadrons. We review the main…
The dispersive two-photon contribution to the K_L --> mu+ mu- decay amplitude is analyzed, using chiral perturbation theory techniques and large-N_C considerations. A consistent description of the decays Pi^0 --> e+ e-, Eta --> mu+ mu- and…