Mr Paul Barker
BA (Oxford), PhD (Manchester)
Research | Current
Superallowed 0+→ 0+ nuclear beta decay depends uniquely on the vector part of the weak interaction. Between T=1 analogue states, the decay strength, or Ft value, when precisely measured, can be used to determine one of Nature's fundamental constants, GV, which plays the same role for the Weak Interaction as the charge on the electron, e, does for the Electromagnetic Interaction. From this one obtains Vud , the largest element of the CKM matrix, and this enables one of the most exacting tests of the Standard Model of particle physics to be made; namely a check on the Unitarity of the first row. At this time, the test fails by more than two standard deviations.
Of the possible decays which can be studied, nine have yielded Ft values with high precision. Each requires careful measurement of the decay energy, its halflife and the branching ratio. The Auckland group has made a strong contribution to this data base, originally in our home laboratory AURA2, and now transferred to the ANU Nuclear Physics Laboratory in Canberra.
Selected publications and creative works (Research Outputs)
- Barker, P. H. (2005). MeV Energy Measurements for Symmetry Tests. Paper presented at Beyond Einstein, Physics for the 21st Century, Bern, Switzerland. 11 July - 15 July 2005. Related URL.
- Barker, P. H., Barnett, I. C., Baxter, G. J., & Byrne, A. P. (2004). Half-life of the superallowed positron emitter O-14. PHYSICAL REVIEW C, 70 (2)10.1103/PhysRevC.70.024302
- Barker, P. H., & Byrne, A. P. (2004). Measurement of the Lifetime of 14O and its Ft Value. Paper presented at International Nuclear Physics Conference - INPC 2004, Gothenburg, Sweden. 27 June - 2 July 2004.
- Tolich, N. R., Barker, P. H., Harty, P. D., & Amundsen, P. A. (2003). Energy of the O-14 superallowed positron decay. PHYSICAL REVIEW C, 67 (3)10.1103/PhysRevC.67.035503