2024-03-29T12:42:17Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/36392017-01-27T10:42:23Zcom_10261_61com_10261_4col_10261_314
Gámiz, Elvira
Jamin, Matthias
Pich, Antonio
Prades, Joaquim
Schwab, Félix
2008-04-17T23:18:05Z
2008-04-17T23:18:05Z
2007
PoS - Proceedings of Science (KAON) 008 (2007)
1824-8039
http://hdl.handle.net/10261/3639
A very precise determination of V_us can be obtained from the semi-inclusive hadronic decay width of the tau lepton into final states with strangeness. The ratio of the Cabibbo-suppressed and Cabibbo-allowed tau decay widths directly measures (V_us/V_ud)^2, up to very small SU(3)-breaking corrections which can be theoretically estimated with the needed accuracy. Together with previous LEP and CLEO data, the recent measurements by Babar and Belle of some Cabibbo-suppressed tau decays imply V_us= 0.2165 +- 0.0026_exp +- 0.0005_th, which is already competitive with the standard extraction from K_l3 decays. The uncertainty is largely dominated by experimental errors and should be easily reduced with the high statistics of the B factories, providing the most accurate determination of this parameter. A 1% experimental precision on the Cabibbo-suppressed tau decay width would translate into a 0.6% uncertainty on V_us.
eng
openAccess
Theoretical progress on the V_us determination from tau decays
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