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%% tau physics lepton universality section
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Tree-level Higgs exchanges in supersymmetric new physics models can
induce modifications of lepton universality of order
0.1\%~\cite{Krawczyk:1987zj}, smaller but close to the present
experimental accuracy of $\approx 0.2\%$~\cite{Pich:2006nt}. As
discussed in Ref.~\cite{Bona:2007qt}, \superb can probably measure
lepton universality to $0.1\%$ or better. However the measurement is
limited by experimental systematic uncertainties on the measurement of
the tau leptonic branching fractions and the tau lifetime, as the
modest progress provided by the existing $B$ Factories also
confirms~\cite{Lusiani:2007cb}.  Therefore it cannot be advocated that
the \superb advantages in terms of luminosity are crucial and
necessary for the advancement of this particular sector, although
large statistical samples will be an advantage to reduce experimental
systematic uncertainties.
