Dispersion relations and Omnès representations for $K\to \pi \pi$ decay amplitudes

We derive dispersion relations for decay, using the Lehmann-Symanzik-Zimmermann formalism, which allows the analytic continuation of the amplitudes with respect to the momenta of the external particles. No off-shell extrapolation of the field operators is assumed. We obtain generalized Omnès representations, which incorporate the and S-wave phase shifts in the elastic region of the direct and crossed channels, according to the Watson theorem. The contribution of the inelastic final-state and initial-state interactions is parameterized by the technique of conformal mappings. We compare our results with previous dispersive treatments and indicate how the formalism can be combined with lattice calculations to yield physical predictions. Received: 14 October 2002 / Published online: 14 February 2003     

Analytic parametrization of high energy forward scattering amplitude II. K±p and π±p scattering

The K^±p and π^±p forward scattering amplitudes are parametrized in terms of functions which are analytic in the cut E plane and which give the asymptotic behaviour of the total cross sections of the type c (log E/E_o)^γ, E being the lab energy. Fits to high-energy data give, in particular, the best value of γ: around it we find, however, a large interval of positive values of γ which are also admissible on the basis of the χ² estimation.Being equally good from the point of view of the existing experimental data, the different asymptotic growth rates γ do lead to different predictions, e.g., of the real part at high energies. A remarkable common feature is, however, a zero in the real part of the π⁺p and π^?p scattering amplitudes, which is predicted by all of our parametrizations to be between 52 and 80 GeV/c of the lab momentum.     

Verification of a localization criterion for several disordered media

We analytically compute a localization criterion in the double-scattering approximation for a set of dielectric spheres or perfectly conducting discs uniformly distributed in a spatial volume which may be either spherical or layered. For every disordered medium, we numerically investigate a localization criterion and examine the influence of the system parameters on the wavelength localization domains.     

Spin effects in hadron scattering at very high energies

In this paper a spin-dependent diffractive model is studied for πN and NN elastic scattering. We find non-trivial results for spin correlation parameters which persist at high energies and have very distinct features in the dip region. It is stressed that these parameters provide good tests of pomeron factorization.     

A diffractive model including spin for pp elastic scattering at very high energy

In this paper we present a theoretical diffractive model for spin-dependent proton-proton scattering at very high energies using an extended version of the Chou-Yang model. The model describes a wide t range, but in this paper we use it for small t values. We obtain estimates of the ratio of spin-dependent to spin-independent amplitudes, β, consistent with a previous phenomenological analysis. Next we estimate the asymmetry, Σ, expected in a certain polarized inclusive process at high energy. We then compute the size of polarization effects in pp total cross-section measurements, using polarized beam and target at very high energy. Our estimates of the latter two quantities indicate that their measurement would not provide a sensitive test of pomeron factorization.     

Some theoretical aspects of the presence of spin in proton proton elastic scattering

Some theoretical aspects on the problem of spin in proton proton elastic scattering in the range of energy starting from few GeV/c up to ISR energies are discussed.Presented at the Symposium on Hadron-Hadron Scattering at High Energies, Liblice, Czechoslovakia, June 16–21, 1975.I thank A.Martin and J.Soffer for their help in preparing this talk.     

Eikonal description of nucleon-nucleon polarizations

Nucleon-nucleon elastic polarization data are analyzed within an eikonal framework in the range 6?plab?45 GeV/c and |t| 2.5 GeV/V². The isovector component is found to be dominated by a nearly exchange degenerate ρ-A₂ contribution while the isoscalar part requires both a lower lying Regge-pole exchange and an asymptotic pomeron contribution.     

Impact picture predictions for\bar p p andpp elastic scattering at CERN collider,FNAL collider,LHC and SSC

We present in detail the predictions on \(\bar p\) p andpp total and elastic differential cross-sections for energies 0.546 to 40 TeV obtained on the basis of the impact picture, including the Coulomb contribution.