Related papers: Diffractive Neutral Pion Production, Chiral Symmet…
We show that diffractive production of a single neutral pion in photon-induced reactions at high energy is dynamically suppressed due to the approximate chiral symmetry of QCD. These reactions have been proposed as a test of the odderon…
The interference between the Pomeron and possible odderon mechanisms of diffractive pi+pi- photoproduction results in charge asymmetry of the produced pions. The observation of charge asymmetry of pions at moderate M_{pi+pi-} will be an…
We discuss how the evasive Odderon signal can be enhanced by final state interactions. We suggest the charge asymmetry of pion spectra in diffractive pi+pi- photoproduction as a promising signature of the Odderon exchange.
We study Pomeron-Odderon interference effects giving rise to charge and single-spin asymmetries in diffractive electroproduction of a pi+ pi- pair. We calculate these asymmetries originating from both longitudinal and transverse…
Charge asymmetries in diffractive electroproduction of two mesons are proportional to the interference of Pomeron and Odderon exchange amplitudes. We calculate in the framework of QCD and in the Born approximation a forward-backward charge…
Threshold neutral pion photoproduction on light nuclei is studied in the framework of baryon chiral perturbation theory. We obtain a general formula for the electric dipole amplitude in the special case of neutral pion photoproduction on a…
The neutrino pion production off the nucleon is traditionally described in the literature by means of the weak excitation of the Delta(1232) resonance and its subsequent decay into N pi. Here, we present results from a model that includes…
Within the framework of a simple model, we study single-spin asymmetries for pion production in hadron-hadron collisions at high-energies with one hadron polarised. The asymmetries are generated via a mechanism of final (initial) state…
The neutral pion photoproduction on the proton near threshold has a very small scattering cross section when compared to the charged channels, which in ChPT is explained by strong cancellations between the lowest order pieces. Therefore it…
Photoproduction of neutral and charged pions off nucleons and deuterium has been precisely calculated in baryon chiral perturbation theory. I review the predictions with the accurate data that have become available over the last few years.…
We investigate threshold pion photoproduction in the framework of heavy baryon chiral perturbation theory. We give the expansion of the electric dipole amplitude $E_{0+}$ to three orders in $\mu$, the ratio of the pion to nucleon mass, and…
I review the interesting tale of the electric dipole amplitude in neutral pion photoproduction and the resulting consequences. I also discuss why there is new life related to P--wave multipoles. Electroproduction is briefly touched upon.
The neutral pion electroproduction on the proton is considered in the framework phenomenological model based on the PCAC, current algebra with hard pions and chiral symmetry breaking interaction. The s- wave differential cross-section 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…
In diffractive hadronic scattering processes, the Pomeron trajectory, originating from Regge theory, significantly contributes to the behavior of the total and differential cross sections; the same holds for the description of the proton…
We present an exploratory study of two pion photo-- and electroproduction off the nucleon in the threshold region. To calculate the pertinent amplitudes, we make use of heavy baryon chiral perturbation theory. We show that due to finite…
We investigate pion photoproduction off the proton in a manifestly gauge-invariant chiral unitary extension of chiral perturbation theory. In a first step, we consider meson-baryon scattering taking into account all next-to-leading order…
The leading-particle effect and the factorization property of the scattering amplitude in the impact parameter space are used to study semiclassical production of pions in the central region. The mechanism is related to the isospin-uniform…
In this talk I review the main features of the coherent/diffractive pion production by neutrinos on nuclei. The method is based on PCAC and relates the reaction $\textbf{boson} + \textbf{nucleus} \to \textbf{pion} + \textbf{nucleus}$ to…
The light-cone distribution amplitudes for the axial current are derived within the instanton vacuum model (IVM), which incorporates nonperturbative effects including spontaneous chiral symmetry breaking. This allows to extend applicability…