相关论文: Comments on "eta -> gamma gamma Decay Width via th…

The radiative decays of the pseudoscalar mesons $P=(\pi^0,\eta,\eta')$ are of special interest as they provide an experimental window on the electromagnetic and colour chiral $U_A(1)$ anomalies. $\pi^0\to\gamma\gamma$ is well described by…

We have searched for the bottomonium eta_b(1S) via the hindered magnetic dipole (M1) photon transition Upsilon(3S) -> gamma eta_b(1S). No evidence for such a transition is found in the data sample of 4.7 x 10^6 Upsilon(3S)'s collected with…

The radiative decays $\eta'(\eta)\rta\gamma\gamma$ are discussed. The modifications of the conventional PCAC formulae due to the gluonic contribution to the flavour singlet axial anomaly are given. The decay constants satisfy a modified…

Background: Optical potentials are crucial ingredients for the prediction of nuclear reaction rates needed in simulations of the astrophysical \gamma-process. Associated uncertainties are particularly large for reactions involving…

This study outlines a numerical methodology aimed at rectifying the neutron scattering cross-sections of fundamental elements across a range of low neutron energies typically employed in general neutron scattering experiments. By using the…

Precise data for quasi-free photoproduction of $\eta$ mesons off the deuteron have been measured at the Bonn ELSA accelerator with the combined Crystal Barrel/TAPS detector for incident photon energies up to 2.5 GeV. The $\eta$-mesons have…

Incoherent photoproduction of eta-mesons on the deuteron is considered. The main attention is paid to the region above the S11(1535) resonance where rather narrow resonance like structure in the total cross section extracted for gamma n ->…

We analyse the proton recoil energy and angular distribution of the radiative beta-decay of the neutron to leading order in the large baryon mass expansion by taking into account the contributions of the proton-photon correlations. We show…

A transformation group approach to the prior for the parameters of the beta distribution is suggested which accounts for finite sets of data by imposing a limit to the range of parameter values under consideration. The relationship between…

In cond-mat/9907125 the low-temperature behavior of a model for RNA secondary structure was studied. It is claimed that the model exhibits a breaking of the replica symmetry, since the width of the distribution P(q) of overlaps may converge…

Data for phi -> gamma (eta-pizero) are analysed using the KK loop model and compared with parameters of a0(980) derived from Crystal Barrel data. The eta-pi mass spectrum agrees closely and the absolute normalisation lies just within…

The double polarization observable $E$ and the helicity dependent cross sections $\sigma_{1/2}$ and $\sigma_{3/2}$ were measured for $\eta$ photoproduction from quasi-free protons and neutrons. The circularly polarized tagged photon beam of…

Very recently, a new hadronic exotic state $\eta_1(1855)$ at the invariant mass spectrum of $\eta\eta^{'}$ was observed by the BESIII Collaboration. According to its properties, such as the spectroscopy and decay width, the $\eta_1(1855)$…

eta photoproduction data on the proton up to E=2 GeV are interpreted within a chiral constituent quark formalism, which embodies all known three and four star resonances. This study confirms the need for a new S11 resonance, with M=1.780…

A new measurement of the rare, doubly radiative decay eta->pi^0 gamma gamma was conducted with the Crystal Ball and TAPS multiphoton spectrometers together with the photon tagging facility at the Mainz Microtron MAMI. New data on the…

In above mentioned article [1] assumptions of possible systematic errors of our experiment on measuring of the neutron lifetime [2] have been made. In the given comment we are obliged to explain, that assumptions made in [1] are erroneous.…

In recent years there has been considerable activity in using gamma-ray bursts as cosmological probes for determining global cosmological parameters complementing results from type Ia supernovae and other methods. This requires a…

Nowadays the field of searching for a new physics became a very interesting subject in a light meson decays due to a recent results from KTeV collaboration which found the 3.3\sigma\ disagreement between Standard Model theory and their…

In the Standard Model (SM) we calculate the decay rate of the neutron radiative beta decay to order "O(\alpha^2/\pi^2 ~ 10^{-5})", where "\alpha$"is the fine--structure constant, and radiative corrections to order "O(\alpha/\pi ~ 10^{-3})".…

[Background] Despite the importance of light-ion fusion in nucleosynthesis, a limited amount of data exists regarding the de-excitation following fusion for such systems. [Purpose] To explore the characteristics of alpha emission associated…