Resonance Production and Correlations of Neutral and Charged Pions

Abstract

A b s t r a c t . The influence of the production of the meson resonances e,f and Q on semi-inclusive no multiplicities and nOnO correlations is investigated in a Correlated J e t Model (CJM) for resonance production besides direct pion production. The model takes into account an exact global isospin conservation provided by a coherent state projection procedure and the local isospin conservation at the re8onance decay vertices. The resulting semi-inclusive no multiplicity (no)rr, yields a sufficient description of the data a t FXAL energies. This quantity is decomposed in the modcl into contributions from direct no production and from no coming from the decay of the different resonanms. Furthcrmore, the predictions of the CJM for the semiinclusive xOnO correlation coefficient is given and found t o be consistent with present data. Resonanzproduktion und Korrolatmionen zwischen goladenon und neutralen x-MesonenI n h a l t s i i b e r s i c h t . I n einem korreliertcn J e t Modell (CJM), dw ncben direkter Erzeugung von n-Mesonen die Produktion von Resonanzen beriichiehtigt, wird der EinflnO der mesonischen Resonanzen e,f und o auf semiinklusive d' Multiplizitiiten und zOno Korrelationen untersucht. Das Modell enthllt durch Projektion koharenter Zustinde cine exakte globale IRospinerhaltung nnd lokale Isoapinerhaltung an den Resonanzzerfallsvertizes. Die resultierenden semiinklnsiven no Multiplizitiiten <no), liefcrn eine ausreichende Beschreibung der bci FNAL-Energien gemessenen Daten. I m Modell wird (no)n, in HcitrLge direkt erzeugter no-Mesonen iind verxhiedener Resonanzzerfalle eerlegt. Weiterhin werdcn die Voraussagen des CJM fur den Yemiinklusiven nono Iiorrelationskoeffizienten angegeben. Sie sind in tbcrcinstiinmung mit den vorhandenen Daten.a lot, of information on the charge and rnultiplicity structure of niultiple production.One of the most st,riking features of the data at high energies (P,~,, 2 50 (:eV/c) is the st.rong positive correlation between iieut ral and charged pions indicating genuine two (or more) particle tiynamical correlations [ I, 21. This is corifiriiied by several studies in the framework of different cluster inodels [3]. Recently it has been found that low mass resonances like the c0 meson also in this energy range are a dominant, source for particle production ; the p0 to pion ratio for example is approximat,cly energy independent [ 2 1. Naturally, the neutml-charged correlation can be expected to he strongly enhanced by the production of resonances which decay into neutral and charged pions. Therefore the problem of neutral-charged correlations is reconsidered here taking into account the meson resonances Q (in all charge states), ( I ) , and f. 11 AIIII. I%ysik. 7. l'olgo, 11d. 35 1G2 K. J. BIEBL, M. KLEII, and R. ~A H N I I A U E R