Related papers: $\pi N\to \eta N$ process in a $\chi$QM approach
The influence of the phi-meson on the nucleon properties in the chiral soliton model is discussed.
The $\eta \to \pi^+ \pi^- \pi^0 \gamma$ decay is discussed in the general context of Chiral Perturbation Theory (ChPT), assuming that the low--energy constants (counter--terms) are saturated by vector-meson resonances. The $\eta \to \pi^+…
The three complex form factors entering the $\Delta\to N\gamma^\ast$ vertex are calculated to ${\cal O}(\epsilon^3)$ in the framework of a chiral effective theory with explicit \Delta(1232) degrees of freedom included. It is shown that the…
We present a relativistic procedure for the chiral expansion of the two-pion exchange component of the $NN$ potential, which emphasizes the role of intermediate $\pi N$ subamplitudes. The relationship between power counting in $\pi N$ and…
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…
We have investigated the $\Lambda_c^+\to n\pi^+\pi^0$ decay process using the chiral unitary approach, by considering that the nucleon resonance $N(1535)$ could be dynamically generated through $S$-wave pseudoscalar meson-octet baryon…
A covariant spectator constituent quark model is applied to study the gamma N -> Delta(1600) transition. Two processes are important in the transition: a photon couples to the individual quarks of the Delta(1600) core (quark core), and a…
We study the electromagnetic form factors of a nucleon in next-to-leading order chiral perturbation theory (CPT) in the case where one of the nucleons is off its mass shell. We calculate the leading nonanalytic contributions to relevant…
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…
We review the actual state in the description of the NN interaction by means of chiral constituent quark models. We present a series of relevant features that are nicely explained within the quark model framework.
The processes $\tau^- \to \pi^- \pi^0 \nu_{\tau}$ and $e^{+}e^{-} \to \pi^{+} \pi^{-}$ are considered within the chiral Nambu--Jona-Lasinio model with taking into account the pion final state interactions beyond the leading $1/N_c$…
We analyse the interplay between nucleon-nucleon potentials deduced from chiral perturbation theory and a coarse grained representation of the short distance interactions by delta-shells potentials below a certain cut-off distance. While we…
We study the disintegration $\tau^- \to \pi^-\ell^+\ell^-\nu_\tau$, where $l$ denotes either an electron or a muon. This process requires knowledge about the $W^*\gamma^*\pi$ interaction, which is modeled using Resonance Chiral Theory.…
We apply the chiral color dielectric model to low- and medium-energy scattering within the coupled $\pi$N and $\pi\Delta$ system. Dynamic baryon states in which quarks are confined by the scalar color-dielectric field are constructed in…
We calculate within the Extended Nambu--Jona-Lasinio model the leading in $1/N_c$ contribution to $\gamma\gamma\to\pi^0\pi^0$ to all orders in the external momenta and quark masses. This result is then combined with the known two-loop…
We consider the two-nucleon system at next-to-next-to-next-to-leading order (N^3LO) in chiral effective field theory. The two-nucleon potential at N^3LO consists of one-, two- and three-pion exchanges and a set of contact interactions with…
The processes involving $K^{-}p, KN, \Sigma\pi, \Lambda\pi,\Sigma\eta, \Lambda\eta$ coupled channels are studied in the nonperturbative chiral approach. An effective potential is constructed using a chiral meson-baryon Lagrangian at lowest…
I summarize two recent applications of chiral perturbation theory to electromagnetic reactions on deuterium: elastic electron-deuteron scattering, and Compton scattering on deuterium. Both calculations have now been carried out to three…
In mean field approximation, we study a chiral soliton of the linear sigma model with two flavors at finite temperature and density. The stable soliton solutions are calculated with some appropriate boundary conditions. Energy and radius of…
I present some recent results on neutral pion photo- and electroproduction in the threshold region and discuss the low energy theorem for $E_{0+}$ and some novel ones for the $P$-waves. I also study the two-pion production process $\gamma N…