Review of τ lifetime and leptonic branching ratio measurements
Abstract
After several years of rapid developments measurements of the τ lifetime and leptonic branching ratios have reached an unprecedented level of precision. The world average lifetime, τ τ = 290.21 ± 1.15 fs, is significantly shorter than values of a decade ago. The individual experimental results are summarized, and comparisons are made between the different techniques for measuring the lifetime. Leptonic branching ratio measurements have surpassed the forward leaps of precision achieved with the lifetime, Be = 17.786 ± 0.072% and B μ = 17.317 ± 0.078%, while the central values have remained stable over time. The updated averages lead to flawless agreement with the predictions of lepton universality, to better than 0.3% for most of the coupling constant ratios.
- Publication:
-
Nuclear Physics B Proceedings Supplements
- Pub Date:
- May 1997
- DOI:
- 10.1016/S0920-5632(97)00206-5
- Bibcode:
- 1997NuPhS..55..107W