High precision analytical description of the allowed <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>β</mml:mi></mml:math> spectrum shape

Abstract

Beta decay is a process that reveals the structure of the standard model and its possible extensions. This reviews provides a description of the allowed beta-spectrum shape in view of ongoing and planned measurements searching for physics beyond the standard electroweak model and weak magnetism. The formalism presents a description of the underlying physics. The derived expression for both Fermi and Gamow-Teller transitions is accurate for low to medium Z nuclei.