|Vud| from T = 1/2 mirror transitions and the role of atom and ion traps

摘要

Precision correlation measurements in nuclear beta decay using atom and ion traps have made significant progress since the last ENAM2004 Conference. We review here the achievements and plans of different projects and discuss for each of them their potential to contribute to the determination of the Vud element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix. This matrix element has traditionally been determined from the analysis of data in nuclear superallowed 0~+ → 0~+ transitions, neutron decay and pion beta decay but can also independently be determined from data in nuclear mirror transitions. This requires the measurement of correlation parameters in such decays to determine the Gamow-Teller to Fermi mixing ratio which, in most cases, dominates the error on the extracted value of |Vud|.