Search for the G-parity irregular term in weak nucleon currents extracted from mirror beta decays in the mass 8 system

T. Sumikama, K. Matsuta, T. Nagatomo, M. Ogura, T. Iwakoshi, Y. Nakashima, H. Fujiwara, M. Fukuda, M. Mihara, K. Minamisono, T. Yamaguchi, T. Minamisono

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8 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)235-240
Number of pages6
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume664
Issue number4-5
DOIs
Publication statusPublished - 2008 Jun 26

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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