Study of Di-Pion Transitions Among Upsilon3S, Upsilon2S, and Upsilon1S States - High Energy Physics - ExperimentReport as inadecuate




Study of Di-Pion Transitions Among Upsilon3S, Upsilon2S, and Upsilon1S States - High Energy Physics - Experiment - Download this document for free, or read online. Document in PDF available to download.

Abstract: We present measurements of decay matrix elements for hadronic transitions ofthe form UpsilonnS -> pi pi UpsilonmS where n, m = 3, 1, 2, 1, and3, 2. We reconstruct charged and neutral pion modes with the final stateUpsilon decaying to either mu+mu- or e+e-. Dalitz plot distributions for thetwelve decay modes are fit individually as well as jointly assuming isospinsymmetry, thereby measuring the matrix elements of the decay amplitude. Weobserve and account for the anomaly previously noted in the di-pion invariantmass distribution for the Upsilon3S -> pi pi Upsilon1S transition andobtain good descriptions of the dynamics of the decay using the most generaldecay amplitude allowed by partial conservation of the axial-vector currentPCAC considerations. The fits further indicate that the Upsilon2S -> pi piUpsilon1S and Upsilon3S -> pi pi Upsilon2S transitions also show thepresence of terms in the decay amplitude that were previously ignored, althoughat a relatively suppressed level.



Author: CLEO Collaboration: D. Cronin-Hennessy, et al

Source: https://arxiv.org/



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