相关论文: BELLE Data on the $\pi^0 \gamma* \gamma$ Form Fact…
It has previously been shown that a measurement of Arg$(V_{ub})=\gamma$ can be obtained from a triangle construction using ${\cal B}(B^0\to K^+\pi^-)$, ${\cal B}(\bar{B^0}\to K^-\pi^+)$, ${\cal B}(B^\pm\to K^0_s\pi^\pm)$, and ${\cal…
The measurements of the nucleon electromagnetic form factors in the time-like region are reviewed. Several unexpected features deserving new high precision, high statistics measurements are emphasised.
Stringent relations between the $B^{(*)} \to D^{(*)} $ form factors exist in the heavy quark limit and the leading symmetry breaking corrections are known. We reconsider their uncertainty and role in the analysis of recent Belle data for…
We report clear finite size effects in the specific heat and in the relaxation times of a model glass former at temperatures considerably smaller than the Mode Coupling transition. A crucial ingredient to reach this result is a new Monte…
We discuss $(\pi^0,\eta,\eta')\to\gamma^*\gamma$ transition form factors using the light-front quark model. Our discussion includes the analysis of the mixing angles for $\eta-\eta'$. Our results for $Q^2…
For the spacelike momenta k of the virtual photon gamma^*, the pi^0(p) gamma^*(k) gamma(k') transition form factor is considered in the coupled Schwinger-Dyson and Bethe-Salpeter approach in conjunction with the generalized impulse…
We briefly summarize the status with electromagnetic nucleon form factors, and give in this framework, arguments to study the angular dependence of the differential cross section and single-spin polarization phenomena (polarized target or…
By means of QCD sum rules in local-duality limit, we analyze the behaviour of the form factors for the transitions of a real and a virtual photon to some pseudoscalar meson as functions of the involved momentum transfer. Except for the…
We report on recent improvements for the $B\to\pi$ form factor. The updated value of $|V_{ub}|$ is presented.
A new approach to the parameterization of pion form factors is presented and for illustration applied to the pion vector form factor. It has the correct analytic structure, is at low energies consistent with recent high accuracy analyses of…
We reconsider the QCD predictions for the radiative decay $B\to \gamma \ell \nu_\ell$ with an energetic photon in the final state by taking into account the $1/E_\gamma, 1/m_b$ power-suppressed hard-collinear and soft corrections from…
We report the observation of the decay $D^{0} \to \phi \gamma$ with a statistical significance of $5.4\sigma$ in $78.1 \ifb$ of data collected by the Belle experiment at the KEKB $e^+ e^-$ collider. This is the first observation of a…
Determination of the fine structure constant alpha and search for its possible variation are considered. We focus on a role of the fine structure constant in modern physics and discuss precision tests of quantum electrodynamics. Different…
We consider the issue of determining the D0-Dbar0 width difference Delta Gamma_D experimentally. The current situation is reviewed and suggestions for further study are given. We propose a number of D0 decay modes in addition to those…
We reconsider the `long-range' component of the radiative transition $B \to K^* \gamma$. A careful analysis of the vector dominance amplitude $B \to V_1 V_2 \to V_1 \gamma$ is carried out, with emphasis on the role of gauge invariance. The…
We summarise our current results for calculations of the form factors for $B \to K^* \gamma$, and their extrapolation to the physical b-quark mass.
Large discrepancy of the p-wave phase shift data $\delta_{1}(\nu)$ of the $\pi$-$\pi$ scattering from those of the dispersion calculation is pointed out. In order to determine which is correct, the pion form factor $F_{\pi}(\nu)$, which is…
To further precision studies with $B \to K^{(*)} \ell \ell$ decays in the high-$q^2$ window uncertainties related to the operator product expansion (OPE) need to be scrutinized. How well can the OPE describe $B \to K^* (\to K \pi) \ell…
We obtain the electromagnetic form factors of the $\gamma N\Delta$ transition by analyzing recent pion-electroproduction data using a fully relativistic dynamical model. Special care is taken to satisfy Ward-Takahashi identities for the…
We analyse various $U(1)_{EM}$ form factors of mesons at strong coupling in an $\mathcal{N}=2$ flavored version of $\mathcal{N}=4$ $SYM$ which becomes conformal in the UV. The quark mass breaks the conformal symmetry in the IR and generates…