The minimal Standard Model extension with the Weinberg operator does accommodate the observed neutrino masses and mixing, but predicts a neutrinoless double beta ($0νββ$) decay rate proportional to the effective electron neutrino mass, which can be then arbitrarily small within present experimental limits. However, in general $0νββ$ decay can have an independent origin and be near its present experimental bound; whereas neutrino masses are generated radiatively, contributing negligibly to $0νββ$ decay. We provide a realization of this scenario in a simple, well defined and testable model, with potential LHC effects and calculable neutrino masses, whose two-loop expression we derive exactly. We also discuss the connection of this model to others that have appeared in the literature, and remark on the significant differences that result from various choices of quantum number assignments and symmetry assumptions. In this type of models lepton flavor violating rates are also preferred to be relatively large, at the reach of foreseen experiments. Interestingly enough, in our model this stands for a large third mixing angle, $\sin^2θ_{13} \gtrsim 0.008$, when $μ\rightarrow eee$ is required to lie below its present experimental limit.
It is firmly believed that a signal of neutrinoless double beta decay can unquestionably confirm the Majorana nature of neutrinos. However we notice that a Majorana neutrino mass induced after some neutrinoless double beta decay processes can be accidentally cancelled by another Majorana neutrino mass induced before any neutrinoless double beta decay processes. This realistic cancellation can simultaneously allow an observable neutrinoless double beta decay and a vanishing Majorana neutrino mass. In consequence a future discovery of neutrinoless double beta decay cannot fully rule out the poss…
本文简要介绍了无中微子双β衰变实验的理论分析。提出了“可观测”β的理论界限<m>。利用β的实验界<m>，得到了m_l-cos{2 θ_12}平面上的允许区域，其中m_l代表最轻中微子质量。结果表明，结合未来无中微子双β衰变和{}^3 H β衰变实验的可能结果，可以排除Majorana中微子。还讨论了约束两个马约拉纳阶段之一的可能性。
Minimal supersymmetric standard model with gauge mediated supersymmetry breaking and neutrinoless double beta decay
本文应用具有规范介导超对称破缺和三线性R宇称破坏的最小超对称标准模型描述无中微子双β衰变。利用最近的CLEO结果，对来自B到（X，γ）过程的参数空间的限制进行了详细的研究。讨论了双核子和π子交换实现无中微子双β衰变的重要性以及胶子和中性伴子对这一过程的贡献。我们从几种中重开壳层核中0 nu β β的不可观测性出发，推导了三线性R宇称破缺参数lambda_{111} '在不同规范介导破缺情形下的新极限.一般来说，它们比其他分析中已知的更强。最后，对未来的无中微子双β衰变计划作了一些展望。
We discuss the systematic decomposition of the dimension nine neutrinoless double beta decay operator, focusing on mechanisms with potentially small contributions to neutrino mass, while being accessible at the LHC. We first provide a (d=9 tree-level) complete list of diagrams for neutrinoless double beta decay. From this list one can easily recover all previously discussed contributions to the neutrinoless double beta decay process, such as the celebrated mass mechanism or "exotics", such as contributions from left-right symmetric models, R-parity violating supersymmetry and leptoquarks. More…
Neutrino Masses, Mixing and Neutrinoless Double-Beta Decay
有效马约拉纳质量的预测|<m>| in neutrinoless double- beta decay in the case of 3-neutrino mixing and massive Majorana neutrinos are reviewed.本文还讨论了寻找无中微子双β衰变和对$|<m>| \gtap 0.01$ eV敏感的实验的物理潜力，以提供关于中微子质量谱类型、中微子质量绝对尺度和PMNS中微子混合矩阵中Majorana CP破坏相的信息。
The constraints on baryogenesis models obtained from an observation of neutrinoless double beta decay are discussed. The lepton number violating processes, which can underlie neutrinoless double beta decay, would together with sphaleron processes, which are effective in a wide range of energies, wash out any primordial baryon asymmetry of the universe. Typically, if a mechanism of neutrinoless double beta decay other than the standard light neutrino exchange is observed, typical scenarios of high-scale baryogenesis will be excluded. This can be achieved by different methods, e.g. through the o…
We discuss the impact of the observation of neutrinoless double beta decay on the washout of lepton number in the early universe. Neutrinoless double beta decay can be triggered by a large number of mechanisms that can be encoded in terms of Standard Model effective operators which violate lepton number by two units. We calculate the contribution of such operators to the rate of neutrinoless double beta decay and correlate it with the washout of lepton number induced by the same operators in the early universe. We find that the observation of a non-standard contribution to neutrinoless double …
Constraints on neutrinoless double beta decay from neutrino oscillation experiments
我们表明，在一个一般模型的框架下，与混合的三个马约拉纳中微子和中微子质量的层次，Bugey和Krasnoyarsk反应堆中微子振荡实验的结果意味着强烈的限制，有效马约拉纳质量|<m>| that characterizes the amplitude of neutrinoless double beta decay .我们得到进一步的限制，|<m>| from the data of the atmospheric neutrino experiments.我们讨论了未来长基线中微子振荡实验结果对无中微子双β衰变的可能意义。
We study the neutrinoless double beta decay in the colored Zee-Babu model. We consider three cases of the colored Zee-Babu model with a leptoquark and a diquark introduced. The neutrino masses are generated at two-loop level, and the constraints given by tree-level flavor violation processes and muon anomalous magnetic moment $(g-2)_μ$ have been considered. In our numerical analysis, we find that the standard light neutrino exchange contribution can be canceled by new physics contribution under certain assumption and condition, leading to a hidden neutrinoless double beta decay. The condition …
Neutrinoless double beta decay, solar neutrinos and mass scales
我们通过结合大气和太阳中微子数据和无中微子双β衰变现象，得到中微子质量的界限，|< m>| are envisaged from future 0νββ-experiments.太阳中微子数据的不同解决方案被认为是。对于大混合角解，|< m>| \leq 0.01 eV would strongly disfavour an inverted hierarchy of the neutrino masses.
