I. Bender

K+N scattering in the constituent quark model

Abstract We calculate S-wave phase shifts of the KN system in the framework of a nonrelativistic quark model, using variational methods (generator coordinates). We show that the I = 0 channel is determined by the QCD residual interaction, which leads to a small repulsion, and that the I = 1 channel receives strong repulsive contributions already from quark exchange. We discuss the relevance and physical origin of these results. We furthermore construct an approximate local potential extracted from the nonlocal cluster interaction.

LEPTONIC DECAYS OF BARYONS

Formulae are obtained for the differential decay rate, lepton spectrum, and partial lifetime for the leptonic decays of baryons, which cover effects down to the order of one percent. A weak, linearq2-dependence of the form factors is included, which should be a sufficiently good approximation in the physicalq2-range allowed in the decays. The one percent discrepancy arises as a consequence of the above-mentioned approximation to the form factors, whose value and slope atq2=0 are left open in the formulae;SU(3) symmetry, CVC, and PCAC yield an estimate for these parameters.

Fixed poles in photoproduction of charged pions

SummaryTwo fixed Khuri poles, suggested by field-theoretical models, as well as two Regge poles (A2 and B) are used in order to interpret π+ and π- photoproduction off nucleons. In the framework of this model the (evasive) pion is not Reggeized. The model, involving only four free parameters, is found to be in good agreement with the experimental data for photon energies above 8 GeV.RiassuntoSi usano tanto due poli fissi di Khuri, suggeriti da modelli di teoria di campo, quanto due poli di Regge (A2 e B) per interpretare la fotoproduzione di π+ e π- fuori dai nucleoni. Nello schema di questo modello il pione (evasivo) non è reggeizzato. Si trova che il modello, che comporta solo quattro parametri liberi, è in buon accordo con i dati sperimentali per energie del fotone superiori a 8 GeV.РезюмеДва фиксированных полюса Хури, предполагаемые моделями теории поля, так же как два полюса Редже (A2 и B) используются для интерпретации фоторождения π+ и π- на нуклонах. В рамках этой модели (неуловимый) пион не является реджеизованным. Получается, что эта модель, включающая только четыре свободных параметра, хорошо согласуется с экспериментальными данными для энергий фотонов выше 8 ГэВ.

A dual resonance model for the π π π{\cal N}\bar {\cal N}-five-point function

AbstractAssuming that the Bardakçi-RueggB5-function is relevant for the dynamical description of hadronic single particle production processes we construct a model for the π π π

Rapidly converging path integral formalism. I, Quantum mechanics

{\cal N}\bar {\cal N}

Kaon-nucleonS-wave phase shifts in a QCD-motivated quark model

-five-point function. For the invariant functions appearing in a suitably chosen invariant decomposition an ansatz is made in terms ofB5-functions multiplied by polynomials of the invariant variables which are required by factorization.The Regge trajectories introduced are those of the π, ϱ,P′, ω and

First and second class weak hadronic currents and their implications for Kl3 decays in an extended Cabibbo model

\mathcal{N}