Wolfenstein-like parametrization of the neutrino mixing matrix

Current experimental data allow the zero value for one neutrino mass, either m 1 = 0 or m 3 = 0. This observation implies that a realistic neutrino mass texture can be established by starting from the limit (a) m 1 = m 2 = 0 and m 3 = 0 or (b) m 1 = m 2 = 0 and m 3 = 0. In both cases, we may introduce a particular perturbation which ensures the resultant neutrino mixing matrix to be the tri-bimaximal mixing pattern or its viable variations with all entries being formed from small integers and their square roots. We find that it is natural to incorporate this kind of neutrino mass matrix in the minimal Type-II seesaw model with only one heavy right-handed Majorana neutrino N in addition to the SU (2) L Higgs triplet ∆ L . We show that it is possible to account for the cosmological baryon number asymmetry in the m 3 = 0 case via thermal leptogenesis, in which the one-loop vertex correction to N decays is mediated by ∆ L and the CP-violating asymmetry of N decays is attributed to the electron flavor.

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“…This pattern has actually been conjectured in Ref. [17], but here we illustrate how it can be obtained from M ν .…”

Section: Neutrino Mixing Patternssupporting

confidence: 81%

Deviations from tribimaximal neutrino mixing in the type-II seesaw model and leptogenesis

et al. 2007

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“…So it is unpractical to expand the matrix in powers of one of the nondiagonal elements, like the Wolfenstein parametrization of the quark mixing matrix [14]. Xing [15] has made the Wolfenstein-like parametrization for the neutrino mixing matrix, but they have to use much higher orders of the nondiagonal elements. In the quark mixing pattern, all the non-diagonal elements are small, so we may take it for granted that the mixing is a small modification to the unit matrix.…”

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confidence: 99%

A new parametrization of the neutrino mixing matrix

2004

Physics Letters B

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The neutrino mixing matrix is expanded in powers of a small parameter λ, which approximately equals to 0.1. The meaning of every order of the expansion is discussed respectively, and the range of λ is carefully calculated. We also present some applications of this new parametrization, such as to the expression of the Jarlskog parameter J, in which the simplicities and advantages of this parametrization are shown.Key words: neutrinos, neutrino mixing matrix, parametrization PACS: 14.60. Pq, 12.15.Ff, 13.15.+g, 14.60.Lm In recent years, there have been abundant experimental data strongly suggesting the mixing of different generations of neutrinos, just analogous to that of quarks. The K2K [1] and Super-Kamiokande [2] experiments indicated that the atmospheric neutrino anomaly is due to the ν µ to ν τ oscillation with almost the largest mixing angle of θ atm ≈ 45• . The KamLAND [3] and SNO [4] experiments told us that the solar neutrino deficit was caused by the oscillation from ν e to a mixture of ν µ and ν τ with a mixing angle approximately of θ sol ≈ 34• . On the other hand, the non-observation of the ν e to ν e oscillation in the CHOOZ [5] experiment showed that the mixing angle θ chz is smaller than 3• at the best fit point [6,7].These experiments not only confirmed the oscillations of neutrinos, but also measured the mass-squared differences of the neutrino mass eigenstates (the * Corresponding author. Like the Cabibbo-Kobayashi-Maskawa (CKM) [8,9] matrix for quark mixing, the neutrino mixing matrix is described by the unitary Maki-Nakawaga-Sakata (MNS) [10] matrix V , which links the neutrino flavor eigenstates ν e , ν µ , ν τ to the mass eigenstates ν 1 , ν 2 , ν 3 ,

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“…(12). The considerations from this Section indicate that current data and the precision of future experiments on θ 23 and θ 13 limit the realistic values of m and n between 1 and 3.…”

Section: Neutrino Mixingmentioning

confidence: 97%

“…In the present paper we wish to propose a parametrization of the neutrino mixing matrix in terms of a small parameter λ, whose magnitude is interestingly around 0.2, i.e., close to the Wolfenstein parameter used to parametrize the CKM matrix [10]. In any parametrization of the neutrino mixing matrix (for earlier attempts, see [11,12,13]), it is convenient to start from a reference matrix and describe deviations from it. Our reference matrix is the one corresponding to exact bimaximal neutrino mixing.…”

Section: Introductionmentioning

confidence: 99%

A parametrization for the neutrino mixing matrix

Rodejohann

2004

Phys. Rev. D

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We propose a flexible and model independent parametrization of the neutrino mixing matrix, which takes advantage of the fact that there are up to three small quantities in neutrino mixing phenomenology: (i) the deviation from maximal mixing of solar neutrinos, (ii) the mixing matrix element U e3 and (iii) the deviation from maximal mixing of atmospheric neutrinos. It is possible to quantify those three observations with a parameter λ ∼ 0.2, which appears at least linearly in all elements of the mixing matrix. The limit λ → 0 corresponds to exact bimaximal mixing. Present and future experiments can be used to pin down the power of λ required to usefully describe the observed phenomenology. Observing that the ratio of the two measured mass squared differences is roughly λ 2 allows to further study the structure of the Majorana mass matrix. We comment on the implications of this parametrization for neutrinoless double beta decay and on the oscillation probabilities in long-baseline experiments.

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Wolfenstein-like parametrization of the neutrino mixing matrix

Cited by 35 publications

References 35 publications

Deviations from tribimaximal neutrino mixing in the type-II seesaw model and leptogenesis

Deviations from tribimaximal neutrino mixing in the type-II seesaw model and leptogenesis

A new parametrization of the neutrino mixing matrix

A parametrization for the neutrino mixing matrix

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