Theories of the ABC effect

Structure in two-pion production in thedd→αXreaction

“…A double-nucleon exchange model, also proposed in the seventies [15] and using separate diagrams for the three different peaks, showed a much poorer angular distribution [3] and the authors were incapable of obtaining an absolute normalization. In his survey of all ABC experiments and models, Barry [16] tried to improve the original ∆∆-model and to extend it to pd → 3 HeX but with little success; his model has, in particular, problems in reproducing the spectra away from the ABC peaks. Better results were achieved in a chiral bag model [17], taking into account 80 diagrams to fourth order in the πNN coupling constant, but this model still failed in the details.…”

The Systematization of Legal Values around Justice

“…And, finally, natural law uses an equalizing criterion but moves away from idealism because it does not suppose that positive law loses its legal status to the extent that the idea of justice is not realized or, at least, insofar as it is opposed to it. 61 Whatever the position, it is no less true that the question of knowledge of justice and its very consistency are conflicts that are far from having been resolved to the satisfaction of all. The law is fair because it contains justice while, for the same reasons, every law is unfair because it is always an iustum imperfectum, it is not only the discrepancy between the ideal and the realization that can create a reason for negative evaluation, but also, taking a step further, under the logical aspect of justice, latent injustice emerges.…”

Multi-pion production in the dd→αX reaction

“…A double-nucleon exchange model, also proposed in the seventies [15] and using separate diagrams for the three different peaks, showed a much poorer angular distribution [3] and the authors were incapable of obtaining an absolute normalization. In his survey of all ABC experiments and models, Barry [16] tried to improve the original ∆∆-model and to extend it to pd → 3 HeX but with little success; his model has, in particular, problems in reproducing the spectra away from the ABC peaks. Better results were achieved in a chiral bag model [17], taking into account 80 diagrams to fourth order in the πNN coupling constant, but this model still failed in the details.…”

“…The phenomenon is believed to originate from a largely kinematic enhancement in the production of two pions, but all previous attempts to give a quantitative description have so far had only limited success. In particular, the theoretical models for the np → dX [8,9,10,11] and pd → 3 HeX [12,10] reactions have problems in reproducing the angular dependences [3,12]. A recently published model for dd → αX [13] has, however, had remarkable success in reproducing data.…”