Double β Decay and the Axial Strength

Abstract

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Quenching of the weak axial strength gA is discussed and relations of this quenching to the nuclear matrix elements of double beta decays are highlighted. An analysis of Gamow-Teller transitions in the mass range A = 62 − 142 is presented and its results are compared with those of many previous works. The enhancement of the axial charge is discussed for first-forbidden pseudoscalar β transitions. Higher-forbidden β transitions are introduced and their role in determining the effective value of gA is examined, in particular from the point of view of the β-decay half-lives and the shapes of electron spectra of forbidden non-unique β transitions.

Keywords

• double beta decay
• Gamow-Teller beta decay
• quenching of weak axial coupling
• forbidden beta decay
• enhancement of weak axial charge
• electron spectral shapes