Pionic Contribution to Neutrinoless Double Beta Decay

TL;DR

This paper investigates the impact of pionic contributions on neutrinoless double beta decay, emphasizing the importance of accurate nuclear matrix element calculations for understanding neutrino properties.

Contribution

It introduces a non-relativistic quark model to evaluate pionic effects, which are usually negligible but become dominant in certain decay processes.

Findings

Pionic contributions significantly affect nuclear matrix elements.

Non-relativistic quark model effectively estimates pionic effects.

Results highlight the importance of including pionic effects in decay analysis.

Abstract

It is well known that neutrinoless double decay is going to play a crucial role in settling the neutrino properties, which cannot be extracted from the neutrino oscillation data. It is, in particular, expected to settle the absolute scale of neutrino mass and determine whether the neutrinos are Majorana particles, i.e. they coincide with their own antiparticles. In order to extract the average neutrino mass from the data one must be able to estimate the contribution all possible high mass intermediate particles. The latter, which occur in practically all extensions of the standard model, can, in principle, be differentiated from the usual mass term, if data from various targets are available. One, however, must first be able reliably calculate the corresponding nuclear matrix elements. Such calculations are extremely difficult since the effective transition operators are very short ranged. For such operators processes like pionic contributions, which are usually negligible, turn out to be dominant. We study such an effect in a non relativistic quark model for the pion and the nucleon.