Measurement of <math><mtext>D</mtext><msub><mi></mi><mn>s</mn></msub><msup><mi></mi><mn>−</mn></msup><mtext> → τ</mtext><msup><mi></mi><mn>−</mn></msup><mtext>ν</mtext><msub><mi></...

• Autores: Dova, María Teresa; L3 Collaboration
• Año de publicación: 1997
• Idioma: español castellano
• Tipo de recurso: artículo
• Materia: Física; L3 detector; Leptonic decays; Heavy flavour mesons; Física
• Institución: Universidad Nacional de La Plata

Using a data sample of 1 475 000 Z → qq̄(γ) events collected during 1994 with the L3 detector at LEP, we have studied the purely leptonic decays of heavy flavour mesons, $\text{D}{}_{\mathrm{s}}{}^{\mathrm{-}}\text{→ τ}{}^{\mathrm{-}}\text{ν}{}_{\mathrm{\tau }}$ and $\text{B}{}^{\mathrm{-}}\text{→ τ}{}^{\mathrm{-}}\text{ν}{}_{\mathrm{\tau }}$. A signal is observed in the invariant mass distribution M(γDs−) corresponding to the decay sequence $\text{D}{}^{\mathrm{\ast -}}\text{→ γD}{}_{\mathrm{s}}{}^{\mathrm{-}}$, $\text{D}{}_{\mathrm{s}}{}^{\mathrm{-}}\text{→ τ}{}^{\mathrm{-}}\text{ν}{}_{\mathrm{\tau }}$, $\text{τ}{}^{\mathrm{-}}\text{→ l}{}^{\mathrm{-}}\text{ν}{}_{\mathrm{l}}\text{ν}{}_{\mathrm{\tau }}$. The branching fraction for $\text{D}{}_{\mathrm{s}}{}^{\mathrm{-}}\text{→ τ}{}^{\mathrm{-}}\text{ν}{}_{\mathrm{\tau }}$ decays is measured to be $\text{β}\text{(D}{}_{\mathrm{s}}{}^{\mathrm{-}}\text{→ τ}{}^{\mathrm{-}}\text{ν}{}_{\mathrm{\tau }}\text{) = 0.074 ± 0.028(stat) ± 0.016(syst) ± 0.018(norm)}$. No signal of $\text{B}{}^{\mathrm{-}}\text{→ τ}{}^{\mathrm{-}}\text{ν}{}_{\mathrm{\tau }}$ decays is observed in the data, corresponding to an upper limit on the branching franction $\text{β(}\text{B}{}^{\mathrm{-}}\text{→ τ}{}^{\mathrm{-}}\text{ν}{}_{\mathrm{\tau }}\text{) < 5.7 × 10}{}^{\mathrm{-4}}$ at 90% CL.
Facultad de Ciencias Exactas