Improved measurement of the $pi ightarrow mbox{e} u$ branching ratio

A new measurement of the branching ratio R-e/mu= Gamma(pi(+) -> e(+)nu + pi(+) -> e(+)nu gamma)/Gamma(pi(+) -> mu(+)nu+pi(+) -> mu(+)nu gamma) resulted in R-e/mu(exp) = [1.2344 +/- 0.0023(stat) +/- 0.0019(syst)] x 10(-4). This is in agreement with the standard model prediction and improves the test of electron-muon universality to the level of 0.1%.