Constraints on NJL four-fermion effective interactions from neutrinoless double beta decay

Abstract

We study the contribution of a heavy right-handed Majorana neutrino to neutrinoless double beta decay (0νββ) via four-fermion effective interactions of Nambu-Jona-Lasinio (NJL) type. In this physical scenario, the sterile neutrino contributes to the nuclear transition through gauge, contact, and mixed interactions. Using the lower limit on the half-life of 0νββ from the KamLAND-Zen experiment, we then constrain the effective right-handed coupling between the sterile neutrino and the W boson: $$ {\mathcal{G}}_R^W $$ G R W . Eventually, we show that the obtained bounds are compatible with those found in the literature, which highlights the complementarity of this type of phenomenological study with high-energy experiments.

Generation of the CMB cosmic birefringence through axion-like particles, sterile and active neutrinos

“…The upper limit of G R value should be smaller than 10 −4 . It is constrained by the W ± decay width [57], studying double beta-decay 0νββ experiment [58], W boson mass tension [59], the precision measurement of finestructure constant α [44] and regarding N e R as a DM particle in the XENON1T experiment and astrophysical observations [44].…”

“…Now, in order to calculate the forward scattering term in (7), we need to find the commutator [H 0 I (t), D 0 i j (p)], then evaluate the expectation value [H 0 I (t), D 0 i j (p)] according to the following operator expectation value b † r i (q )b r j (q) = (2π) 3 δ 3 (q − q )δ rr δ i j 1 2 f N (x, q). (64) To this end, one can substitute (59-63) into (58) and then (7) to find the time evolution of the density matrix components which is obtained as follows…”