Neutrino oscillation constraints on neutrinoless double-beta decay

Abstract

We have studied the constraints imposed by the results of neutrino oscillation experiments on the effective Majorana mass | m | that characterizes the contribution of Majorana neutrino masses to the matrix element of neutrinoless double-beta decay. We have shown that in a general scheme with three Majorana neutrinos and a hierarchy of neutrino masses (which can be explained by the see-saw mechanism), the results of neutrino oscillation experiments imply rather strong constraints on the parameter | m |. From the results of the first reactor long-baseline experiment CHOOZ and the Bugey experiment it follows that | m | 3 × 10 −2 eV if ∆m 2 2eV 2 (∆m 2 is the largest mass-squared difference). Hence, we conclude that the observation of neutrinoless doublebeta decay with a probability that corresponds to | m | 10 −1 eV would be 1 a signal for a non-hierarchical neutrino mass spectrum and/or non-standard mechanisms of lepton number violation. PACS number(s): 14.60.Pq, 23.40.-s Typeset using REVT E X 2

Neutrinoless double-β decay with three or four neutrino mixing

“…Therefore, if scheme A is realized in nature the effective Majorana mass in ββ 0ν decay can be as large as m 3 ≃ m 4 ≃ ∆m 2 LSND ≃ 0.45 − 1.4 eV [24][25][26][27]. On the other hand, in scheme B neutrinoless double-β decay is strongly suppressed [25][26][27].…”

“…In this case neutrinoless double-β decay is possible. It has been shown in [25][26][27] that the results of neutrino oscillation experiments imply a rather stringent upper bound (about 6 × 10 −3 eV) for the effective Majorana mass in neutrinoless double-β decay in the scheme with mixing of three neutrinos and a mass hierarchy. In principle the effective Majorana mass (1.1) can be vanishingly small because of cancellations among the contributions of the different mass eigenstates.…”

“…The results of the CHOOZ experiment [47] and the Super-Kamiokande atmospheric neutrino data [11] imply that |U e3 | 2 is small (|U e3 | 2 5 × 10 −2 ) and there is an upper limit of about 6 × 10 −3 eV for the contribution | m | 3 to the effective Majorana mass in ββ 0ν decay [25][26][27]. Since there is no lower bound for |U e3 | 2 from experimental data, | m | 3 could be very small.…”

Neutrino oscillation experiments and limits on lepton-number and lepton-flavor violating processes

“…Taking into account that the probability P ee for solar neutrinos is significantly lower than one, leads to a small value of |U e3 | 2 [9]. In that case one has…”

“…With this approximation, m αβ is symmetric. The mass measured in neutrinoless double beta decay (0νββ) is the (ee) element of this matrix and has been considered by several authors [9,10]. However, the complete matrix is rarely analyzed in terms of phenomenological consequences, except for the elements m eµ and m µµ in Refs.…”