β-decay studies for shape coexistence

<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m1"><mml:mrow><mml:mi>β</mml:mi></mml:mrow></mml:math> decay has played a key role in studies of shape coexistence throughout the nuclear chart. This has been mainly due to the sensitivity in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m2"><mml:mrow><mml:mi>γ</mml:mi></mml:mrow></mml:math> -ray and conversion electron spectroscopy that can be achieved following the population of excited states by <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m3"><mml:mrow><mml:mi>β</mml:mi></mml:mrow></mml:math> decay. In some regions, the spectroscopic studies using <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m4"><mml:mrow><mml:mi>β</mml:mi></mml:mrow></mml:math> decay have been the first to suggest the presence of shape coexistence; in others, they have reinforced the suggestion and provided important spectroscopic data. The present work reviews some of the key regions, with a prime focus on the neutron-rich side of the valley of stability, where <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m5"><mml:mrow><mml:mi>β</mml:mi></mml:mrow></mml:math> -decay measurements have played an important role.