無微中子雙貝他衰變是一個檢測微中子特性的重要反應，若微中子屬馬約拉那粒子，則可在實驗上觀察到此反應且輕子數不守恆，本文利用新擬合微中子振盪數據給予此反應中的參數---等效馬約拉那質量---限制，在微中子質量相近的前提下，兩種質量層級會給出不同的結果，且CP相的差異對結果影響明顯。

The neutrinoless double beta decay is an important process to test the nature of neutrinos. If neutrinos are Majorana particles, the decay can be observed in experiment and the lepton number is not conserved. We derive some formulae of the parameter of this process called the effective Majorana mass and use new fit data of neutrino oscillations to give constraints on it. With the assumption that all neutrinos have similar mass, we conclude that the two mass hierarchies would give different values and the CP phases have significant effect.

1 Introduction . . . . . . . . . . . . . . . . . . . . 1
2 Theoretical Basis . . . . . . . . . . . . . . . . . .4
　2.1 Dirac Mass . . . . . . . . . . . . . . . . . . . 4
　2.2 Majorana Mass . . . . . . . . . . . . . . . . . . 5
　2.3 Neutrino Mass for One Generation . . . . . . . . 7
　2.4 Mixing Matrix . . . . . . . . . . . . . . . . . . 8
　2.5 Mass Matrix . . . . . . . . . .. . . . . . . . . 8
3 The Effective Majorana Mass Analysis . . . . . . . . 10
4 Summary . . . . . . . . . . . . . . . . . . . . . . .14
Appendix . . . . . . . . . . . . . . . . . . . . . . . 15
　A Elements of Mass Matrix . . . . . . .. . . . . . . 15
　B Global Fit Data . . . . . . .. . . . . . . . . . . 16
References . . . . . . . . . . . . . . . . . . . . . . 17

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