We consider $ρ$ meson contributions to neutrinoless double beta decay amplitude stemming from the hadronization of the short distance quark-electron currents. These contributions are evaluated within vacuum dominance approximation. The one and two $ρ$ exchange contributions affect the Fermi transition nuclear matrix element in a way that lead to near cancellations in the same chirality, left-left and right-right, short range amplitudes when these new contributions are combined with the conventional short range amplitudes, while the left-right amplitude almost triples. This then necessitates the inclusion of $ρ$ exchange amplitudes in any phenomenological study, like in left-right theories.
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…
A significant signal of neutrinoless double beta decay can be consistent with the existence of light quasi-Dirac neutrinos. To demonstrate this possibility, we consider a realistic model where the neutrino masses and the neutrinoless double beta decay can be simultaneously generated after a Peccei-Quinn symmetry breaking.
In a class of left-right symmetric models for linear seesaw, a neutrinoless double beta decay induced by the left- and right-handed charged currents together will only depend on the breaking details of left-right and electroweak symmetries. This neutrinoless double beta decay can reach the experimental sensitivities if the right-handed charged gauge boson is below the 100 TeV scale.
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。
Motivated by recent intensive experimental efforts on searching for neutrinoless double beta decays, we present a detailed quantitative analysis on the prospect of resolving neutrino mass ordering in the next generation $^{76}$Ge-type experiments.
In this paper we analyze the neutrinoless double beta decay predictions in some scenarios with admixture of pseudo-Dirac and Majorana neutrinos in the 3 and 3+1 neutrino frameworks. We found that some of the cases can be falsifiable in near-term and future generations of neutrinoless double beta decay experiments even for the normal neutrino mass hierarchy. In the 3+1 framework we consider the sterile neutrino with a mass of the order of 1 eV. The complementarity between cosmological constraints and the future sensitivity for the next generations of the neutrinoless double beta decay searches …
We discuss the relation between lepton number violation at high and low energies, particularly, the constraints on baryogenesis models, which would be implied by an observation of neutrinoless double beta decay. The primordial baryon asymmetry can be washed out by effective lepton number violating operators triggering neutrinoless double beta decay in combination with sphaleron processes. A generic conclusion is that popular models of baryogenesis are excluded if a non-standard mechanism of neutrinoless double beta decay, i.e., other than the standard light neutrino exchange, is observed. Apar…
The neutrinoless double $β$-decay of nuclei is reviewed. We discuss neutrino mixing and 3x3 PMNS neutrino mixing matrix. Basic theory of neutrinoless double $β$-decay is presented in some details. Results of different calculations of nuclear matrix element are discussed. Experimental situation is considered. The Appendix is dedicated to E. Majorana (brief biography and his paper in which the theory of Majorana particles is given)
Associated with two TeV-scale leptoquark scalars, a dark matter fermion which is the neutral component of an isotriplet can mediate a testable neutrinoless double beta decay at one-loop level. The dark matter fermion with determined mass and spin-independent scattering can be verified by the future dark matter direct detection experiments. We also discuss the implications on neutrino masses and baryon asymmetry.
Sterile neutrinos of mass up to a few tens of TeV can saturate the present experimental bound of neutrinoless double beta decay process. Due to the updated nuclear matrix elements, the bound on mass and mixing angle is now improved by one order of magnitude. We have performed a detailed analysis of neutrinoless double beta decay for the minimal Type I seesaw scenario. We have shown that in spite of the naive expectation that the light neutrinos give the dominant contribution, sterile neutrinos can saturate the present experimental bound of neutrinoless double beta decay process. However, in or…
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。
Neutrinoless double beta decay is the most powerful tool to probe not only for Majorana neutrino masses but for lepton number violating physics in general. We discuss relations between lepton number violation, double beta decay and neutrino mass, review a general Lorentz invariant parametrization of the double beta decay rate, highlight a number of different new physics models showing how different mechanisms can trigger double beta decay, and finally discuss possibilities to discriminate and test these models and mechanisms in complementary experiments.
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…
Neutrinoless double beta decay (NDBD) is the only experiment that could probe the Majorana nature of the neutrino. Here we study the theoretical implications of NDBD for models yielding tri-bimaximal lepton mixing like A4 and S4.
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 …
We discuss a consistency test which makes it possible to discriminate unknown nuclear background lines from neutrinoless double beta decay with only one isotope. By considering both the transition to the ground state and to the first excited $0^+$ state, a sufficiently large detector can reveal if neutrinoless double beta decay or some other nuclear physics process is at work. Such a detector could therefore simultaneously provide a consistency test for a certain range of Majorana masses and be sensitive to lower values of the effective Majorana mass.
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 …
From the standard seesaw mechanism of neutrino mass generation, which is based on the assumption that the lepton number is violated at a large (~10exp(+15) GeV) scale, follows that the neutrinoless double-beta decay is ruled by the Majorana neutrino mass mechanism. Within this notion, for the inverted neutrino-mass hierarchy we derive allowed ranges of half-lives of the neutrinoless double-beta decay for nuclei of experimental interest with different sets of nuclear matrix elements. The present-day results of the calculation of the neutrinoless double-beta decay nuclear matrix elements are bri…
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.
We present a new channel of the neutrinoless double beta decay. In this scenario neutrinos not only oscillate inside the nucleus but also interact with an external non-uniform magnetic field. We assume that the field rotates about the direction of motion of the neutrino and show, that for a certain speed of rotation the half-life of the $0\nu2β$ decay may be significantly lowered.
We present the possible influence on the half-life of neutrinoless double beta decay coming from the existence of $n$ extra spatial dimensions. The half-life in question depends on the mass of the electron neutrino. We base our analysis on the Majorana neutrino mass mechanism in Arkani-Hamed--Dimopoulos--Dvali model.
