The alignment correlation terms in the β-ray angular distributions from purely spin aligned 8Li and 8B have been measured to search for the G-parity violating induced tensor term gII in the weak nucleon currents. The gII was extracted from the present alignment correlation terms, combined with the known β - α angular correlation terms and weak magnetism. This analysis permits an experimental determination of all the matrix elements necessary to extract gII. As a result, the induced tensor term was extracted as gII / gA = - 0.28 ± 0.28 (stat.) ± 0.15 (syst.) at a 1σ (68%) level. The present data and the data in the mass A = 12 and 20 systems were analyzed under the KDR model in which medium effects including the off-shell effect and meson exchange current were taken into account. We determined the 1-body contribution to be ζ = - (0.13 ± 0.13) × 10-3 MeV-1 and the 2-body contribution to be λ = + (0.27 ± 0.97) × 10-3 at a 1σ level.
|Number of pages||6|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|Publication status||Published - 2008 Jun 26|
ASJC Scopus subject areas
- Nuclear and High Energy Physics