  A new measurement of $B_{\pi e2}$, the $\pi^+ \to e^+\nu(\gamma)$ decay
branching ratio, is currently under way at the Paul Scherrer Institute. The
present experimental result on $B_{\pi e2}$ constitutes the most accurate test
of lepton universality available. The accuracy, however, still lags behind the
theoretical precision by over an order of magnitude. Because of the large
helicity suppression of the $\pi_{e2}$ decay, its branching ratio is
susceptible to significant contributions from new physics, making this decay a
particularly suitable subject of study.
