相关论文: Replay to hep-ph/0606266
The radiative $\phi\to\pi^0\eta\gamma$ decay is discussed emphasizing the effects of the $a_0$(980) scalar resonance which dominates the high values of the $\pi^0\eta$ invariant mass spectrum. In its lowest part, the proposed amplitude…
We perform an amplitude analysis of B+- -> phi(1020) K*(892)+- decay with a sample of about 384 million BBbar pairs recorded with the BABAR detector. Overall, twelve parameters are measured, including the fractions of longitudinal f_L and…
We complete the recalculation of the available two-loop expressions for the reaction \gamma\gamma->\pi\pi in the framework of chiral perturbation theory. Here, we present the results for charged pions. The cross section and the values of…
We propose a parametrization for two-body nonleptonic $B$ meson decays, in which the various topologies of amplitudes are counted in terms of powers of the Wolfenstein parameter $\lambda\sim 0.22$. The weak phases and the amplitudes are…
We present the first ab initio calculation of a radiative transition of a hadronic resonance within quantum chromodynamics (QCD). We compute the amplitude for $\pi\pi \to \pi\gamma^\star$, as a function of the energy of the $\pi\pi$ pair…
The study of radiative phi decays into scalar mesons, with subsequent decay into pi pi gamma, constitutes an important topic at the electron-positron collider DAPHNE. The interference of the respective amplitude with the one for pi+ pi-…
Radiative decays \phi\to\eta\pi^0\gamma and \phi\to\pi^0\pi^0\gamma are studied assuming that these decays are caused through the intermediate a_0(980)\gamma and f_0(980)\gamma states, respectively. Fitting the experimental data of the…
BES data on $J/\psi \to \gamma (\pi^{+} \pi^{-} \pi^{+} \pi^{-})$ have been analyzed into partial waves. We fit with resonances having $J^{PC}=2^{++}$ at 1275 MeV, $0^{++}$ at 1500 MeV, $2^{++}$ at 1565 MeV, $0^{++}$ at 1740 MeV, $2^{++}$…
The amplitude mode is a ubiquitous collective excitation in condensed matter systems with broken continuous symmetry. It is expected in antiferromagnets, short coherence length superconductors, charge density waves, and lattice Bose…
In the SND experiment at VEPP-2M $e^+e^-$ collider the $\phi(1020)\to\pi^0\pi^0\gamma$ decay was studied and its branching ratio was measured: $B(\phi\to\pi^0\pi^0\gamma)=(1.221\pm 0.098\pm0.061)\cdot10^{-4}$. It was shown, that…
The decay $\psi(3686)\to\gamma\pi^+\pi^-\pi^0$ is studied using a sample of $(2712.4\pm14.3)\times10^6$ $\psi(3686)$ events collected with the BESIII detector. The decay $\eta(1405)\to\pi^+\pi^-\pi^0$ is observed for the first time in…
The amplitude analysis has been performed on the pi0 pi0 final state obtained in the pi- p charge exchange process. The pi0 pi0 scattering amplitudes have been obtained for the S and D waves by the Chew-Low extrapolation and the partial…
Amplitude fluctuations of the pairing field are responsible together with phase fluctuations for the pseudogap phenomena in high temperature superconductors. Here we present the more detailed theory of the amplitude and phase fluctuations…
Power-suppressed corrections coming from the end-point integration regions in the amplitude of the process $\gamma^{*}\gamma \to \pi \pi$ at large $Q^2$ and small squared center-of-mass energy $W^2$ are calculated in the QCD hard-scattering…
Partial wave amplitudes have been extracted from accurate data on pbar + p -> pi + pi by a method which incorporates the theoretical constraints of analyticity and crossing symmetry. The resulting solution gives a good fit to the…
Resonances in the reflection probability amplitude r(E) can occur in energy ranges in which the reflection probability R(E)=|r(E)|^2 is 1. They occur as the phase phi(E) defined by r(E) = t*(E)/t(E) = 1e^{i 2phi(E)} undergoes a rapid change…
In this paper we improve and extend a recent analysis which showed that the rho-omega mixing amplitude cannot be unambiguously extracted from the pion electromagnetic form-factor in a model independent way. In particular, we focus on the…
A phenomenological analysis of $K\to \pi\pi\gamma$ ($K_L\to\pi^+\pi^-\gamma$ and $K^+\to\pi^+\pi^0\gamma$) with the direct emission photon is carried out beyond the leading order in the chiral perturbation theory. We show that the…
Three ways are compared of dealing with rescattering effects in $B^{\pm}\to K^0\pi^{\pm}$, in order to determine the weak phase $\gamma$ from these processes and $B^{\pm}\to K^{\pm}\pi^0$. We find that neglecting these contributions…
Based on the effective invariant amplitudes of the transitions $J/\psi\to\gamma X(J^P)$ and $X(J^P)\to\phi\phi$, the spin dependence of the $J/\psi\to\gamma X(J^P)\to\gamma\phi\phi$ decay amplitude is obtained in the case of the…