Summary
The production of
*(1237), the nucleon 3/2-3/2+ isobar, in pair with its antiparticle in proton-antiproton collisions in the laboratory momentum range (3.25÷7) GeV/c is considered in the one-pion exchange model, modified to take into account absorption in the initial and final state due to competition from other open channels according to the theory by Gottfried and Jackson. It is found that this model reproduces well the slope of the differential cross-section, the decay distribution, including an observed small correlation in the decay of the isobar and the anti-isobar, and the energy-dependence of the cross-section, although the absolute magnitude of the cross-section is about a factor of five too big. The production of Y* (1382) and its antiparticle from the same initial state is also briefly discussed.
Riassunto
Nel sistema del laboratorio, nell’intervallo di impulsi (3.5÷7) GeV/c, si studia la produzione dell’
*(1237), l’isobaro 3/2-3/2+ del nucleone, in coppia con la sua antiparticella nelle collisioni protone-antiprotone col modello di scambio di un pione, modificato in modo da tener conto dell’assorbimento negli stati iniziale e finale dovuto alla competizione di altri canali aperti secondo la teoria di Gottfried e Jackson. Si trova che questo modello riproduce bene la pendenza della sezione d’urto differenziale, la distribuzione del decadimento, compresa una piccola correlazione osservata nel decadimento dell’isobaro e dell’antiisobaro, e la dipendenza della sezione d’urto dall’energia, sebbene la grandezza assoluta della sezione d’urto sia troppo grande per un fattore 5 circa. Si discute brevemente la produzione dell’Y* (1382) e della sua antiparticella dallo stesso stato iniziale.
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Svensson, B.E.Y. Absorptive effects in peripheral production processes: the reaction\(\bar p\)p → . Nuovo Cim 39, 667–682 (1965). https://doi.org/10.1007/BF02735832
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DOI: https://doi.org/10.1007/BF02735832