Isospin violation and hyperon semileptonic decays

Mar 11, 1994
12 pages
Published in:
  • Phys.Lett.B 328 (1994) 149-152,
  • Phys.Lett.B 341 (1995) 449 (erratum)
Report number:
  • PRINT-94-0066 (GUELPH),
  • FPRINT-94-14

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Abstract: (Elsevier)
Isospin violation induces a little mixing between the Λ and Σ 0 baryons, and this in turn leads to small changes in matrix elements for weak current involving these particles. The corrections are small but not negligible. The relevant formulae to first order in the mixing are listed in this note. The largest effect is in the ratio of rates of semileptonic decay of Σ + and Σ − (to Λ) which changes by about 6%. A modest improvement in the measurement of the branching ratio of Σ + → Λ e ν would allow the experimental determination of the mixing angle. The SU 3 fitting of axial to vector ratios in the octet is also affected.
  • isospin: violation
  • violation: isospin
  • hyperon: semileptonic decay
  • semileptonic decay: hyperon
  • mixing angle: (Sigma Lambda)
  • Sigma+: branching ratio
  • symmetry: SU(3)
  • coupling constant: vector
  • vector: coupling constant
  • coupling constant: axial