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Regular version of the site

Article

Observation of I (2S) →γηb (1S) Decay

Physical Review Letters. 2018. Vol. 121. No. 23. P. 1-8.
Аушев Т. А., Mizuk R., Pakhlov P., Pakhlova G., Углов Т. В.

We report the observation of I(2S)→γηb(1S) decay based on an analysis of the inclusive photon spectrum of 24.7 fb-1 of e+e- collisions at the I(2S) center-of-mass energy collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. We measure a branching fraction of B[I(2S)→γηb(1S)]=(6.1-0.7-0.6+0.6+0.9)×10-4 and derive an ηb(1S) mass of 9394.8-3.1-2.7+2.7+4.5 MeV/c2, where the uncertainties are statistical and systematic, respectively. The significance of our measurement is greater than 7 standard deviations, constituting the first observation of this decay mode. © 2018 authors. Published by the American Physical Society.