Summary
A total of 2027 K+→π+π0π0 decays at rest were analysed in hydrogen and heavy liquid bubble chambers. The π+ energy spectrum is compared with 3 spectrum shapes:a) linear matrix element,b) linear spectrum, andc) σ resonance hypothesis. The comparison between τ′ and τ decays indicates that they are consistent withI=1 final state and that the agreement is better if one uses the linear matrix element fit in the τ′ decay. Our data fit also well the σ resonance hypothesis form σ∼350 MeV and Γσ∼80 MeV, but do not allow a definite conclusion on this point. The τ′ to τ branching ratio obtained is 0.303±0.009.
Riassunto
Sono stati analizzati complessivamente 2027 decadimenti a riposo K+→π+π0π0 in due camere a bolle, una a idrogeno e una a liquido pesante. Lo spettro di energia del π+ è confrontato con tre forme di spettro:a) elemento di matrice lineare,b) spettro lineare,c) ipotesi della risonanza σ. Il paragone tra i tipi di decadimento τ′ e τ indica che essi sono compatibili con l’ipotesi che lo stato finale abbiaI=1 e che l’accordo è migliore se si usa la forma elemento di matrice lineare nel decadimento τ′. I dati si accordano anche bene con l’ipotesi della risonanza σ perm σ∼350 MeV, ma non permettono di trarre conclusioni definitive su questo punto. Si è ottenuto per il rapporto di decadimento τ′/τ il valore 0.303±0.009.
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Bisi, V., Borreani, G., Cester, R. et al. π+ Energy spectrum and branching ratio of the τ′ decay. Nuovo Cim 35, 768–782 (1965). https://doi.org/10.1007/BF02739340
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DOI: https://doi.org/10.1007/BF02739340