Summary
By fitting the s-wave partial amplitudes for π--scattering, in an unphysical region, we have greatly extended the energy range over which we can examine the contribution from the process π+π→. Our method shows up contributions from this process in states of isotopic spinT=0 andT=1. We can estimate the energiest 1/2 for which this process is important. The form of these contributions is just what would be expected from considerations of angular momenta. Estimates of the amplitudes for π+π→ are deduced. TheT=0 amplitude is large, but in theT=1 case the amplitude is much smaller than the values which have been predicted from the nucleon isovector form factors.
Riassunto
Inserendo le ampiezze parziali dell’ondas per lo scattering π-, in una regione non fisica, abbiamo esteso di molto il campo di energia nel quale possiamo esaminare il contributo del processo π+π→. Il nostro metodo mette in luce i contributi di questo processo negli stati di spin isotopicoT=0 eT=1. Possiamo valutare le energiet 1/2 per le quali questo processo è importante. La forma di questi contributi è proprio quella che ci si sarebbe aspettata da considerazioni sugli impulsi angolari. Deduciamo alcune valutazioni delle ampiezze per π+π→. Nel casoT=0 l’ampiezza è grande, ma nel casoT=1 l’ampiezza è molto minore dei valori predetti dai fattori di forma dell’isovettore nucleonico.
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This work was supported in part by a grant from the U. S. Air Force, European Office, Air Research and Development Command.
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Hamilton, J., Menotti, P., Spearman, T.D. et al. Evidence for pion-pion interactions froms-wave pion-nucleon scattering. Nuovo Cim 20, 519–528 (1961). https://doi.org/10.1007/BF02731500
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DOI: https://doi.org/10.1007/BF02731500