What if a specific neutrinoless double beta decay is absent

TL;DR

This paper explores a seesaw model with two hierarchical right-handed neutrinos, showing that neutrinoless double beta decay can be absent due to destructive interference, impacting experimental searches and theoretical understanding.

Contribution

It demonstrates a scenario where the lighter right-handed neutrino cancels the active neutrino contribution to neutrinoless double beta decay, with implications for neutrino physics and experimental detection.

Findings

The lighter N1 can destructively interfere with active neutrino contributions.

N2 can be heavy enough to not contribute to the decay.

Impacts on direct searches for N1 are analyzed.

Abstract

We consider the seesaw model with two right-handed neutrinos $N_1$ and $N_2$ which masses are hierarchical, and investigate their contribution to the neutrinoless double beta ($0 \nu \beta \beta$) decay. Although the lepton number is broken by the Majorana masses of right-handed neutrinos, such decay processes can be absent in some cases. We present a possibility where the lighter $N_1$ gives a destructive contribution to that of active neutrinos by choosing the specific mixing elements of $N_1$, while $N_2$ is sufficiently heavy not to contribute to the $0 \nu \beta \beta$ decay. In this case the mixing elements of $N_1$ in the charged current interaction are determined by its mass and the Majorana phase of active neutrinos. We then study the impacts of such a possibility on the direct search for $N_1$. In addition, we discuss the consequence of the case when the $0 \nu \beta \beta$ decay in one specific nucleus is absent.