Nuclear structure aspects of neutrinoless double-β decay

Area of Science:

• Nuclear Physics
• Particle Physics

Background:

• Neutrinoless double-beta decay (0νββ) is a hypothetical process crucial for understanding neutrino properties and fundamental symmetries.
• Current theoretical models require accurate nuclear matrix elements for precise 0νββ predictions.

Purpose of the Study:

• To develop a novel theoretical method for calculating 0νββ matrix elements.
• To identify key nuclear states influencing 0νββ decay rates.
• To establish a connection between 0νββ decay calculations and experimental observables.

Main Methods:

• Decomposition of 0νββ matrix elements into sums of products over intermediate nuclear states.
• Analysis of contributions from different intermediate nuclear states, particularly focusing on their angular momentum and parity (J(π)).

Main Results:

• The sum of products is found to be dominated by the J(π)=0(+) ground state of the intermediate nucleus.
• This dominance holds true for both light and heavy neutrino exchange mechanisms in 0νββ decay.
• The decomposition provides a new theoretical tool for nuclear structure calculations.

Conclusions:

• The dominance of the ground state simplifies the calculation and interpretation of 0νββ matrix elements.
• This approach offers a pathway to refine nuclear structure models by comparing with experimental data.
• The method establishes a direct link to two-nucleon transfer experiments, enabling cross-validation of nuclear structure information.