Related papers: Comment on "Surprises in threshold antikaon-nucleo…
We derive a generalized unitarity relation for an arbitrary linear scattering system that may violate unitarity, time-reversal invariance, ${\cal PT}$-symmetry, and transmission reciprocity.
For the first time, elastic pion-nucleon scattering is analyzed in the framework of chiral perturbation theory up to fourth order with explicit $\Delta$ degrees of freedom. The analysis is performed within the heavy-baryon expansion as well…
Based on an approach recently proposed by us, simultaneous $\chi^{2}$-analyses are performed for elastic scattering, direct reaction (DR) and fusion cross sections data for the $^{6}$He+$^{209}$Bi system at near-Coulomb-barrier energies to…
The duality between partonic and hadronic descriptions of physical phenomena is one of the most remarkable features of strong interaction physics. A classic example of this is in electron-nucleon scattering, in which low-energy cross…
We perform ab initio calculations of three-point mass differences in the odd- and even-mass $^{39-49}$Ca isotopes to probe nuclear superfluidity via empirical neutron pairing gaps. We also quantify the sensitivity of those gaps to the…
The measurement of parity violation in the helicity dependence of electron-nucleon scattering provides unique information about the basic quark structure of the nucleons. In this review, the general formalism of parity-violating electron…
Expanded and updated version of a talk originally presented at ``IVth Int. Symp. on Pion--Nucleon Physics and the Structure of the Nucleon'', Bad Honnef, 9--13 September 1991, originally published in $\pi N$ Newletter 6 (1992) 21--32. Table…
We discuss the Pad\'e approximation to the $\pi\pi$ scattering amplitudes in 1--loop chiral perturbation theory. The approximation restores unitarity and can reproduce the correct resonance poles, but the approximation violates crossing…
The master formula approach to chiral symmetry breaking is used to analyze the phase shifts for $\pi\pi$ scattering in the elastic region. The results are in excellent agreement with the data for the phase shifts up to the K-K bar…
We show that, independently of the size of the quark condensate, chiral symmetry correlates the two S-wave \pi\pi scattering lengths. In view of this constraint, the new precision data on K_{e_4} decay allow a remarkably accurate…
Low energy theorems are derived for the coefficients of the effective range expansion in s-wave nucleon-nucleon scattering valid to leading order in an expansion in which both $m_\pi$ and $1/a$ (where $a$ is the scattering length) are…
In the large $N_c$ approximation to $QCD$, the leading $\pp$ scattering amplitude is expressed as the sum of an infinite number of tree diagrams. We investigate the possibility that an adequate approximation at energies up to somewhat more…
We discuss the electromagnetic corrections to the pion-nucleon scattering lengths generated by minimal e. m. coupling from a knowledge of the low energy expansion of the pion-nucleon elastic scattering amplitude as well as from the nucleon…
We review our recent analysis of $\pi K$ scattering data in terms of forward dispersion relations, and also present the parameters of the strange resonances. This work consists of fits to the data that are constrained to satisfy analyticity…
The neutron-neutron scattering length a_nn provides a sensitive probe of charge-symmetry breaking in the strong interaction. Here we summarize our recent efforts to use chiral perturbation theory in order to systematically relate a_nn to…
We consider a new approach to the nucleon-nucleon scattering problem in the framework of the higher-derivative formulation of baryon chiral perturbation theory. Starting with a Lorentz-invariant form of the effective Lagrangian we work out…
We extend our previous study of elastic pion-nucleon scattering in the framework of chiral perturbation theory by performing a combined analysis of the reactions $\pi N \to \pi N$ and $\pi N \to \pi \pi N$. The calculation is carried out to…
We calculate the chiral corrections to Weinberg's prediction for the S--wave $\pi N$ scattering lengths up--to--and--including order ${\cal O}(M_\pi^3)$ making use of heavy baryon chiral perturbation theory. For the isospin--odd scattering…
We consider pion-nucleon scattering in heavy-baryon chiral perturbation theory to third order. All electromagnetic corrections appearing to this order are included. We thus have a consistent description of strong and electromagnetic…
Available experimental data are analyzed to derive simple parametrizations for the mean charged-hadron multiplicities in charged-current neutrino and antineutrino interactions with hydrogen and deuterium targets. The obtained results can be…