相关论文: Has charge symmetry breaking been observed in the …

The status of the theoretical effort to calculate charge-symmetry-breaking pion production reactions will be presented. The main emphasis will be on the d d -> alpha pi0 reaction, especially in relation to the recent IUCF experiment.…

We report the first observation of the charge symmetry breaking d + d -> 4He + pi0 reaction near threshold at the Indiana University Cyclotron Facility. Kinematic reconstruction permitted the separation of 4He + pi0 events from double…

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…

Charge symmetry breaking (CSB) observables are a suitable experimental tool to examine effects induced by quark masses on the nuclear level. Previous high precision data from TRIUMF and IUCF are currently used to develop a consistent…

A model for the d d -> alpha pi pi reaction, based on two parallel N N -> d pi reactions, is extended to incorporate a complete set of input amplitudes. While low-energy cross sections are underestimated, the rich structure observed in the…

Chiral effective field theory predicts a charge symmetry violating (CSB) amplitude for pion-nucleon scattering. This mechanism provides a very large contribution also to the CSB forward-backward asymmetry in the angular distribution of the…

A simple model, based on two parallel and independent N N -> d pi processes, has recently been proposed for two-pion production in the d d -> alpha X reaction. It reproduces all observed features, including the sharp peak structure in…

Charge symmetry breaking (CSB) in the strong interaction occurs because of the difference between the masses of the up and down quarks. The use of effective field theories allows us to follow this influence of confined quarks in hadronic…

We report about the recent results for s- and p-wave pion production in NN -> NNpi within effective field theory and discuss how the charge symmetry breaking in pn -> d pi^0 can be used to extract the strong contribution to the…

The first attempt is made to provide a quantitative theoretical interpretation of the WASA-at-COSY experimental data on the basic double-pion production reactions $pn \to d \pi^0\pi^0$ and $pn \to d \pi^+\pi^-$ in the energy region $T_p =1$…

We show that using parameters consistent with the charge symmetry violating difference between the strong nn and pp scattering lengths provides significant constraints on the amplitude for the dd -> alpha pi0 reaction.

The model for charge symmetry breaking in the reaction np --> dpi^0 applied earlier around the Delta region is used to calculate the integrated forward-backward asymmetry of the cross section close to threshold. The mixing of the pi and eta…

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…

Charge-symmetry breaking in the nucleon-nucleon force is investigated within an effective field theory, using a classification of isospin-violating interactions based on power-counting arguments. The relevant charge-symmetry-breaking…

Coherent photoproduction of the neutral pion and eta meson on the deuteron, $\gamma{d}${$\to$}$\pi^0\eta{d}$, has been experimentally studied at incident photon energies ranging from the reaction threshold to 1.15 GeV. The total cross…

Differential cross sections and photon-beam asymmetries for the gamma p -> pi- Delta++(1232) reaction have been measured for 0.7<cos(theta)<1 and Egamma=1.5-2.95 GeV at SPring-8/LEPS. The first-ever high statistics cross section data are…

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 consider the reaction g+d -> pi+d in a wide energy range around and above the eta-meson photoproduction threshold at backward CM angles of the outgoing pion. Our theoretical analysis is essentially motivated by the recent measurements of…

We demonstrate that one can use the occurrence of charge symmetry breaking as a tool to explore the eta--nucleus interaction near the eta threshold. Based on indications that the cross section ratio of pi+ and pi0 production on nuclei…

We use realistic two- and three-nucleon interactions in a hybrid chiral-perturbation-theory calculation of the charge-symmetry-breaking reaction $dd\to\alpha\pi^0$ to show that a cross section of the experimentally measured size can be…