Improved measurement of psi(2S) decays into tau+ tau-

Using 14M ψ(2S) events collected at BESII, the branching fraction of ψ(2S)→τ+τ− is measured to be Brττ=(3.08±0.21±0.38)×10−3, where the first error is statistical and the second is systematic.

Note:

12 pages, 1 figure

14.60.Fg
13.20.Gd
14.40.Gx
electron positron: colliding beams
electron positron: annihilation
psi(3685): electroproduction
psi(3685): leptonic decay
tau: pair production
tau: leptonic decay
psi(3685): branching ratio

References(13)

Figures(2)

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The expression for the τ+τ- cross section, including the center-of-mass energy spread, initial state radiation correction, vacuum polarization correction, Coulomb interaction correction, and final state radiation correction, is given in BIHEP-TH00/45

J.M. Wu