Bonn 2001 – scientific programme
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T: Teilchenphysik
T 104: Feldtheorie 1
T 104.4: Talk
Monday, March 26, 2001, 17:00–17:15, HS III
Is the CKM matrix unitary? — •Hartmut Abele1, Marga Astruc Hoffmann1, Stefan Baessler1, Dirk Dubbers2, Michael Kreuz1, Ulrich Mayer1, Daniela Mund1, Valery Nesvizhevsky2, Uta Peschke1, Jurgen Reich1, Christian Vogel1, and Oliver Zimmer2 — 1Physikalisches Institut, Univ. Heidelberg, Philosophenweg 12, 69120 Heidelberg — 2Institut Laue-Langevin, B.P. 156, 38042 Grenoble
An important aspect of the universality of the electroweak interaction is the unitarity condition of the Cabibbo-Kobayashi-Maskawa (CKM) matrix. We have measured the beta-asymmetry in the decay of free polarized neutrons. Together with the world average of the neutron lifetime τ and the Fermi decay constant GF, we derive the first element Vud of the CKM matrix. In using this value from a baryon decay, the first element of the CKM matrix has been derived from particle physics alone.The unitarity check differs by more than three sigma standard deviation from unitarity. A measurement of the neutrino asymmetry in the decay of free neutrons is envisaged for this spring.