[en] A fully relativistic, gauge invariant, and nonperturbative calculation of the Δ⁺⁺ magnetic moment, μ_Δ++ is made using equal-time commutation relations (ETCRs) and the dynamical concept of asymptotic SU_F(2) symmetry and realization. The author finds that μ_δ++ = 2.04μ_p, where μ_p is the proton magnetic moment and the Δ mass is 1.232 GeV/c²

[en] The polarization structure of the NN→ΔN transition is presented in a very compact way using two kinds of formalisms. First, the spin-space decomposition adapted for describing Bohr's rules is recalled. Second, the optimal formalism is applied to the transition. It is adapted for taking into account Bohr's relations and explicitly developed in helicity and transversity frames. Tables of transformation are given which simply relate observables defined in different formalisms

[en] Studies of the effects of ρN interactions is essential to the understanding of nuclear reactions at medium and high energies. In the literature, one determines the ρNN and ρNΔ coupling constants by fitting the NN phase shifts, using meson-exchange potentials (MEP). However, there are indications that these coupling constants are too large. The authors have studied these two vertices by using a di-pion model, in which the ρ decays into two π's which interact subsequently with the nucleon. They have found that the ρNN and ρNΔ coupling constants are very sensitive to the value of the πNN range. The use of a πNN range compatible with deep inelastic scattering data leads to much smaller coupling constants than those given by the MEP

No abstract available

[en] With the possibility of dibaryon resonance essentially ruled out, it is important to take a close look at conventional sources of inelasticity in order to explain the nucleon-nucleon interaction above the pion production threshold, in particular unexplained structures in some spin observables. At intermediate energies, the major conventional source of inelasticity is the coupling to the N Δ channel. While the on-shell NN amplitude can be adjusted to the NN scattering phase parameters, it is much harder to constrain individual off-shell NN → NΔ amplitudes. Presently, we are trying to address the following question: when individual partial waves are fitted to the NN phase parameters, how will this reflect in observables which are very sensitive to the off-shell NN → NΔ amplitudes. This test will determine whether the off-shell part of the NN interaction follows consistently, once the on-shell part is fitted to experimental information. This is expected to be the case in a realistic, field-theoretic framework

[en] We calculate the width of the delta resonance at leading two-loop order in baryon chiral perturbation theory. This gives a correlation between the leading pion–nucleon–delta and pion–delta couplings, which is relevant for the analysis of pion–nucleon scattering and other processes.

[en] We present a comprehensive study of two-boson exchange (TBE) corrections in parity-violating electron-proton elastic scattering. Within a hadronic framework, we compute contributions from box (and crossed box) diagrams in which the intermediate states are described by nucleons and Delta baryons. The Delta contribution is found to be much smaller than the nucleon one at backward angles (small epsilon), but becomes dominant in the forward scattering limit (epsilon near 1), where the nucleon contribution vanishes. The dependence of the corrections on the input hadronic form factors is small for Q² < 1 GeV², but becomes significant at larger Q². We compute the nucleon and Delta TBE corrections relevant for recent and planned parity-violating experiments, with the total corrections ranging from -1% for forward angles to 1-2% at backward kinematics.

[en] The experimental and theoretical study of pp → pp π"0 has excited considerable attention, ever since the total cross section measurements were found to be more than five times larger than the then existing theoretical predictions. Advances in technologies led to complete identification of the three body final state and to measurements employing polarized beam on a polarized target. Many of the early theoretical attempts tried to bridge the gap by introducing several mechanisms taking into account only the lowest partial waves. The Julich meson exchange model which took into consideration higher partial waves as well was however found to be inadequate to provide an overall satisfactory reproduction of the data on p-barp-bar → ppπ"0. The purpose of the present contribution is to take into account Sd and Ds channels in pp → ppπ"0 improve the discussion and correlate the resulting pp → p Δ"+p and pp →ppπ"0 amplitudes, so that the importance of Δ contributions can be studied in more detail using the model independent approach

[en] In this paper the deltonic fission (Δ-fission) as a possible dominant fission mode of superheavy elements (SHE) is investigated. The Q_ΔF systematics, dynamical thresholds as well as the competition between the deltonic fission and usual spontaneous fission (SF) are discussed. It is shown that the usual island of stability around the double magic nucleus ²⁹⁸ [114] is suppressed via a deep instability due to the deltonic fission mode. Two islands of relative stability against the deltonic fission dominant mode are predicted to be around the nucleus ³¹⁰ [126] , where T_ΔF = 10^-3.9 yr, for even-even nuclei and around the nucleus ³⁰³ [119] with T_ΔF = 10^-1.0 yr for A-odd nuclei. (Author)

[en] We discuss the possibility that narrow states observed in the Δ₃₃-C system are due to a mechanism of coupling through the continuum when long-lived states are formed in addition to the broad 'super-radiant' state. Expressions and estimates for the narrow widths are presented