PEN: a sensitive search for non-(V-A) weak processes

Authors :: PEN Collaboration
Pocanic, D.
Alonzi, L. P.
Baranov, V. A.
Bertl, W.
Bychkov, M.
Bystritsky, Yu. M.
Frlez, E.
Kalinnikov, V. A.
Khomutov, N. V.
Korenchenko, A. S.
Korenchenko, S. M.
Korolija, M.
Kozlowski, T.
Kravchuk, N. P.
Kuchinsky, N. A.
Mekterovic, D.
Mzhavia, D.
Palladino, A.
Robmann, P.
Rozhdestvensky, A. M.
Shkarovskiy, S. N.
Straumann, U.
Supek, I.
Truoel, P.
Tsamalaidze, Z.
van der Schaaf, A.
Velicheva, E. P.
Volnykh, V. P.
Publication Year :: 2009
Abstract: 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. Thanks to the large helicity suppression of $\pi_{e2}$ decay, the branching ratio is susceptible to significant contributions from new physics, making this decay a particularly suitable subject of study.<br />Comment: 4 pages, 1 figure, talk given at the 18th International Conference on Particles and Nuclei (PANIC08), held 9 -14 November 2008 in Eilat, Israel; to appear in the Proceedings published by North Holland