Evidence for the direct two-photon transition from ψ(3686) to J/ψ.
Phys Rev Lett
; 109(17): 172002, 2012 Oct 26.
Article
em En
| MEDLINE
| ID: mdl-23215179
ABSTRACT
The two-photon transition ψ(3686)âγγJ/ψ is studied in a sample of 1.06×10(8) ψ(3686) decays collected by the BESIII detector. The branching fraction is measured to be (3.1±0.6(stat)(-1.0)(+0.8)(syst))×10(-4) using J/ψâe(+)e(-) and J/ψâµ(+)µ(-) decays, and its upper limit is estimated to be 4.5×10(-4) at the 90% confidence level. This work represents the first measurement of a two-photon transition among charmonium states. The orientation of the ψ(3686) decay plane and the J/ψ polarization in this decay are also studied. In addition, the product branching fractions of sequential E1 transitions ψ(3686)âγχ(cJ) and χ(cJ)âγJ/ψ(J=0,1,2) are reported.
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MEDLINE
Idioma:
En
Revista:
Phys Rev Lett
Ano de publicação:
2012
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Article