PEN experiment: a precise measurement of the π+→e+ν decay branching fraction
/ Authors
P. C. D. Pocanic, L. Alonzi, V. Baranov, W. Bertl, M. Bychkov, Yu.M. Bystritsky, E. Frlež, V. Kalinnikov, N. Khomutov, A. Korenchenko
and 18 more authors
S. Korenchenko, M. Korolija, T. Kozłowski, N. Kravchuk, N. Kuchinsky, D. Mekterović, D. Mzhavia, A. Palladino, P. Robmann, A. Rozhdestvensky, S. Shkarovskiy, U. Straumann, I. Supek, P. Truoel, Z. Tsamalaidze, A. Schaaf, E. Velicheva, V. Volnykh
/ Abstract
A new measurement of Bπe2, the π+→e+ν(γ) decay branching ratio, is currently under way at the Paul Scherrer Institute. The present experimental result on Bπe2 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 πe2 decay, its branching ratio is susceptible to significant contributions from new physics, making this decay a particularly suitable subject of study.
DOI: 10.1063/1.3293904