Super-allowed Fermi beta-decay; the neutron lifetime;

The PERKEO result, λ = G A / G V = - 1.2739 ± 0.0019 , of Abele et al. [Phys. Rev. Lett. 88 (2002) 211801] combines with the GRAVITRAP result of Serebrov et al. [Phys. Lett. B 605 (2005) 72] for the neutron lifetime ( 878.5 ± 0.7 ± 0.3 s ) and the present writerʹs V ud = 0.97468 ± 0.00036 [D.H. Wilkinson, Nucl. Instru. and Meth. A 543 (2005) 497] to yield λ = - 1.2753 ± 0.0005 .