Constraints on the {tau} neutrino mass and mixing from precise measurements of {tau} decay rates
- Northeastern University, Boston, Massachusetts 02115 (United States)
We have derived constraints on the {tau} neutrino mass and fourth generation mixing from an analysis of the partial widths of {tau} lepton decays, in particular, {tau}{sup {minus}}{r_arrow}e{sup {minus}}{bar {nu}}{sub e}{nu}{sub {tau}}, {tau}{sup {minus}}{r_arrow}{mu}{sup {minus}}{bar {nu}}{sub {mu}}{nu}{sub {tau}}, {tau}{r_arrow}{pi}{sup {minus}}{nu}{sub {tau}}, and {tau}{r_arrow}K{sup {minus}}{nu}{sub {tau}}. We present predictions for the {tau} decay widths, allowing for a nonzero {tau} neutrino mass m{sub {nu}{sub {tau}}} and for mixing with a neutrino of mass m{sub {nu}{sub L}}{gt}M{sub Z}/2, which is parametrized using a Cabibbo-like mixing angle {theta}{sub L}. By comparison of these theoretical predictions with the experimental measurements, we obtain the following bounds at the 90{percent} confidence level: m{sub {nu}{sub {tau}}}{lt}42 MeV and sin{sup 2}{theta}{sub L}{lt}0.014. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 441046
- Journal Information:
- Physical Review, D, Vol. 55, Issue 1; Other Information: PBD: Jan 1997
- Country of Publication:
- United States
- Language:
- English
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