ISSN - 15507998, Physical Review D - Particles, Fields, Gravitation and Cosmology, 2012, vol. 86, p. -
Precision measurements of branching fractions for ψ ′→π0J/ψ and ηj/ψ
We present a precision study of the ψ ′→π0J/ ψ and ηJ/ψ decay modes. The measurements are obtained using 106×106 ψ ′ events accumulated with the BESIII detector at the BEPCII e +e - collider operating at a center-of-mass energy corresponding to the ψ ′ mass. We obtain B(ψ ′→π0J/ψ)=(1.26±0.02(stat) ±0.03(syst))×10 -3 and B(ψ ′→ηJ/ψ)=(33.75±0.17(stat)±0.86(syst) )×10 -3. The branching fraction ratio R= B(ψ ′→π0J/ψ)B(ψ ′→η J/ψ) is determined to be (3.74±0.06(stat)±0.04(syst)) ×10 -2. The precision of these measurements of B(ψ ′→π0J/ψ) and R represent a significant improvement over previously published values. © 2012 American Physical Society.