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QCD predictions for the decay of the tau lepton

Journal Article · · Phys. Rev. Lett.; (United States)
The semileptonic decay rate of a heavy lepton is shown to be rigorously calculable by use of perturbative QCD. Even the tau lepton is heavy enough for the perturbative approximation to be accurate. The prediction for the ratio R = GAMMA(tau..-->..v/sub tau/+hadrons)GAMMA(tau..-->..v/sub tau/+e/sup -/+v-italic-bar/sub e/) is 3.29, with an uncertainty of about 1% due to the uncertainty in the ..lambda.. parameter of QCD. Nonperturbative corrections to this prediction are estimated to be on the order of 1%. More importantly, these corrections are shown to be negative because of a fortuitous cancellation of the leading contribution from the gluon condensate. The resulting prediction is significantly smaller than the present experimental result R = 3.65 +- 0.13
Research Organization:
Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208
OSTI ID:
5160157
Journal Information:
Phys. Rev. Lett.; (United States), Journal Name: Phys. Rev. Lett.; (United States) Vol. 60:16; ISSN PRLTA
Country of Publication:
United States
Language:
English