Testing Lepton Universality Using One-prong Hadronic Tau Decays

The branching ratios of the <math> <f> <g>t</g>^-&rarr; h ^-<g>n</g><inf><g>t</g></inf>, <hsp sp="0.167"><g>t</g><sup >-</sup>&rarr; h^-<g>p</g>⁰<g>n</g><inf><g>t</g ></inf></f> </math> and <math> <f> <g>t</g>^-&rarr; h<sup>-< /sup>&ge; 2<g>p</g>⁰ <g>n</g><inf><g>t</g></inf></f> </math > decays have been measured using the 1991&ndash; 1995 data recorded with the OPAL detector at LEP. These branching ratios are measured simultaneously using three selection criteria and found to be <math> <f> B<inf><g>t</g>^-&rarr; <hsp sp="0.167">h^- <g >n</g><inf><g>t</g></inf></inf></f> </math> = (11.98 &plusmn; 0.13 &plusmn; 0.16) , <math> <f> B<inf><g>t</g>^-&rarr; h<sup>-< /sup><g>p</g>⁰ <g>n</g><inf><g>t</g></inf></inf></f> </math > = (25.89 &plusmn; 0.17 &plusmn; 0.29) and <math> <f> B<inf><g>t</g >^-&rarr; h^-&ge; 2<g>p</g>⁰<g>n</g ><inf><g>t</g></inf></inf></f> </math> = (9.91 &plusmn; 0.31 &plusmn; 0.27) 4.060057e-309re the first error is statistical and the second is systematic. These results are in agreement with the current published world average measurements and improve on previous OPAL measurements. The strengths of the weak charged current coupling constants for &tau; 's and muons was tested and their ratio was found to be <math> <f> g <inf><g>t</g></inf>/g<inf><g>m</g></inf></f> </math> = 1.018 &plusmn; 0.010.