相关论文: Analysis of eta production using a generalized Lee…

Data on the total cross sections for the pp -> pp eta, pn -> pn eta, and pn -> d eta reactions and the pp -> pp eta differential cross section near threshold are analysed in a one-meson-exchange model. After including initial and…

Recent data for $\eta$ and $\eta\prime$ photoproduction on protons obtained by the A2 Collaboration at MAMI are presented. The total cross section for $\eta$ photoproduction demonstrates a cusp at the energy corresponding to the…

We extract pole positions for the N(1535) and N(1650) resonances using two different models. The positions are determined from fits to different subsets of the existing $\pi N\to\pi N$, $\pi N\to\eta N$ and $\gamma p\to\eta p$ data and…

The differential cross section for the reaction p(gamma, eta p) has been measured from threshold to 1100 MeV photon laboratory energy. For the first time, the region of the S11(1535) resonance is fully covered in a photoproduction…

Photoproduction of pi0-eta on protons in the energy range from threshold to 1.4 GeV is discussed. The data for representative angular distributions recently obtained at MAMI C are analyzed using an isobar model. The isobars considered are…

Minimum Bias production cross sections of $\eta$ mesons have been measured in 200 AGeV/c S+Au and S+S collisions at the CERN SPS by reconstructing the $\eta \to \gamma\gamma$ decay. The measurements have been made over the rapidity range…

We calculate formation spectra of eta-nucleus systems in (pi,N) reactions with nuclear targets, which can be performed at existing and/or forthcoming facilities, including J-PARC, in order to investigate eta-nucleus interactions. Based on…

We have measured excitation function for dp -> ppp_pi- reaction near the eta production threshold. We observe an enhancement of the counting rate above the threshold which can originate from the production of the eta meson in the reaction…

The N*(1535) resonance contributions to the pn->d\phi reaction are evaluated in an effective Lagrangian model. The \pi-, \eta-, and \rho-meson exchange are considered. It is shown that the contributions from \pi- and \rho-meson exchange are…

Associative photoproduction of $\omega$-meson and $N^{*}(1440)$ on nucleons, $\gamma+N\to\omega+N^{*}(1440)$, in the near threshold region is investigated in a framework employing effective Lagrangians. Besides $\pi$-exchange in t-channel,…

Let $\pi S(t)$ denote the argument of the Riemann zeta-function at the point $s=\tfrac12+it$. Assuming the Riemann hypothesis, we give a new and simple proof of the sharpest known bound for $S(t)$. We discuss a generalization of this bound…

A formalism based on a chiral quark model ($\chi$QM) approach complemented with a one-gluon exchange model, to take into account the breakdown of the $SU(6)\otimes O(3)$ symmetry, is presented. The configuration mixing of wave functions for…

Eta photo- and electroproduction off the nucleon is investigated in an effective lagrangian approach that contains Born terms and both vector meson and nucleon resonance contributions. In particular, we review and develop the formalism for…

Total and differential cross sections for the reaction p(gamma, eta)p have been measured for photon energies in the range from 750 MeV to 3 GeV. The low-energy data are dominated by the S11 wave which has two poles in the energy region…

The pi-N interaction is studied within a meson-exchange model and in a coupled-channels approach which includes the channels pi-N, eta-N, as well as three effective pi-pi-N channels namely rho-N, pi-Delta, and sigma-N. Starting out from an…

The points where diffraction orders emerge or vanish in the propagating spectrum of periodic non-Hermitian systems are referred to as scattering thresholds. Close to these branch points, resonances from different Riemann sheets can…

Pion photo- and electroproduction has been studied at threshold and in the resonance region below W=2GeV. At threshold pi^0 production can be very well explained within a dynamical model derived from an effective chiral Lagrangian. The…

Total cross section for pp->pp eta process has been calculated in meson exchange model. Eta production T-matrices are from our PWA. Initial and final state interactions are disregarded for the moment, due to large uncertainties. Preliminary…

To study cross sections and polarization asymmetries for the processes $e p \to e n \pi^+$ and $e p \to e p \pi^0$ in the backward region, we develop a flexible phenomenological model for nucleon-to-pion transition distribution amplitudes…

We propose a model-independent analysis of near-threshold enhancements using independent S-matrix poles. In this formulation, we constructed a Jost function with controllable zeros to ensure that no poles are generated on the physical…