相关论文: pi-N charge exchange and pi(+)-pi(0) scattering at…

A chiral quark model approach is extended to the study of the $\pi N$ scattering at low energies. The process of $\pi^{-}p \to \eta n$ near threshold is investigated. The model is successful in describing the differential cross sections and…

We review the cross sections for low-energy $\pi^- \gamma$ reactions in the framework of chiral perturbation theory. Charged pion Compton scattering, $\pi^- \gamma\to \pi^-\gamma$, is considered up to one-loop order where the pion's…

The scalar-isoscalar pi-pi phase shifts are calculated in the pi-pi energy range from 600 MeV to 1600 MeV. We use results of the CERN-Cracow-Munich collaboration for the reaction pi^- p --> pi^+ pi^- n on a transversely polarized target at…

We study the reaction $\pi^\pm p \to \pi^\pm \pi^+ n$ and $\pi^- p \to \pi^0 \pi^0 n$ in heavy-baryon chiral perturbation theory of chiral order three from threshold up to pion laboratory kinetic energies of 400 MeV. We find that the…

The reaction ${n} {p} \to {p} {p} \pi^{-}$ has been studied in a kinematically complete measurement with a large acceptance time-of-flight spectrometer for incident neutron energies between threshold and 570 MeV. The proton-proton invariant…

Large momentum transfer reactions such as pion production represent the frontier of Chiral Perturbation Theory and must be understood before more complex reactions can be considered. Pion production is also interesting in its own right, one…

General interest in a precise determination of the threshold pi-pi amplitudes has recently increased markedly due to a controversy regarding the size of <0|qbar q|0>, the scalar quark condensate. This paper examines the current experimental…

We reinvestigate the experimental data on $\omega$--meson production in pion-nucleon collisions based on both an analytical approach and a Monte Carlo simulation. Our analysis allows us to study the kinematical peculiarities of the…

Recent analyses of low-energy pion-nucleon experimental data have provided clear evidence for the violation of the isospin symmetry of the strong interaction. In the present work, it is shown that the single-charge-exchange reaction is the…

The pion-nucleon sigma term ($\sigma_{\pi N}$) is an observable of fundamental importance because embodies information about the internal scalar structure of the nucleon. Nowadays this quantity has triggered renewed interest because it is a…

The standard way to demonstrate the relevance of chiral symmetry for the NN interaction is to consider higher partial waves of NN scattering which are controlled entirely by chiral pion-exchanges (since contacts vanish). However, in…

The results of the analysis of the pi^0 pi^0 scattering amplitudes obtained with pi^- P charge exchange reaction, pi^- P --> pi^0 pi^0 n, data at 9 GeV/c are presented. The pi^0 pi^0 scattering amplitudes show clear f_0(1370) and f_2(1270)…

Measured values of the differential cross sections for pion-nucleon charge exchange, pi- p --> pi0 n, are presented for pi- momenta of 103, 112, 120, 130, 139, 152, and 178 MeV/c. Complete angular distributions were obtained by using the…

We calculate isospin breaking in pion-nucleon scattering in the threshold region in the framework of covariant baryon chiral perturbation theory. All effects due to quark mass differences as well as real and virtual photons are consistently…

The forward--backward asymmetry in n p --> d pi^0, which must be zero in the center-of-mass system if charge symmetry is respected, has been measured to be [17.2 +/- 8 (stat) +/- 5.5 (sys)] * 10^{-4}, at an incident neutron energy of 279.5…

The COMPASS collaboration at CERN has investigated the \pi^- \gamma -> \pi^- \pi^- \pi^+ reaction at center-of-momentum energy below five pion masses, sqrt(s) < 5 m(\pi), embedded in the Primakoff reaction of 190 GeV pions impinging on a…

The doubly differential cross sections for the $^4$He$(\pi^+,\pi^-) 4p$ reaction were calculated using both a two-nucleon sequential single charge exchange model and an intranuclear cascade code. Final state interactions between the two…

We discuss charge symmetry breaking in the $\Lambda N$ interaction. In order to investigate the $\Lambda p$ and $\Lambda n$ interactions at low energies, we propose to utilize the $K^-d\to \pi^-\Lambda p$ and $K^-d\to \pi^0\Lambda n$…

We show that the tail of the chiral two-pion exchange nucleon-nucleon potential is proportional to the $\pi N$ scalar form factor and discuss how it can be translated into effective scalar meson interactions. We then construct a kernel for…

We examine the role of the elementary isoscalar pion--nucleon scattering amplitude in the description of the processes $pp \to pp\pi^0$ and $pp\to d\pi^+$ at threshold. We argue that the presently used tree level dimension two approximation…