We review results from this Workshop on hadronic decays of the tau lepton. New and more precise branching fraction measurements dominate the discussion, particularly for modes involving strange ...particles.
The branching fractions for
τ→
eνν
τ
,
μνν
τ
, and
hν
τ
are measured using data collected with the CLEO detector at the CESR
e
+
e
− collider:
B
e
= 0.1776±0.0006±0.0017,
B
μ
=0.1737±0.0008±0.0018, ...and
B
h
=0.1152±0.0005±0.0012, where the first errors are statistical, the second systematic, and
h refers either to a charged
π or
K. Also measured is the tau mass,
m
τ
=(1778.2±1.4) MeV. Lepton universality is affirmed by the resulting relative branching fractions (
B
μ
/
B
e
=0.9777±0.0063±0.0087,
B
h
/
B
e
=0.6484±0.0041±0.0060) and the charged-current gauge coupling-constant ratios (
g
μ
/
g
e
=1.0026±0.0055,
g
τ
/
g
μ
=0.9990±0.0098). The tau mass result may be recast as a tau neutrino mass limit,
m
ν
τ
, <60 MeV at 95% CL.
Selected results on hadronic decays of the tau lepton from the TAU98 Workshop are reviewed. A comprehensive picture emerges for strange particle branching fractions, and exploration of resonant ...substructure of both strange and non-strange decays is seen to have matured substantially.
We present the first observation of the decay B-->J/psistraight phiK. Using 9.6x10(6) B meson pairs collected with the CLEO detector, we have observed ten fully reconstructed B-->J/psistraight phiK ...candidates, whereas the estimated background is 0.5+/-0.2 event. We obtain a branching fraction of B(B-->J/psistraight phiK) = (8. 8(+3.5)(-3.0)stat+/-1.3syst)x10(-5). This is the first observed B meson decay requiring the creation of an additional s quark pair.
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