Dilations and Light--Heavy Neutrino Mixings

Bielas, Krzysztof; Flieger, Wojciech

doi:10.5506/aphyspolb.48.2213

Cited by 3 publications

(4 citation statements)

References 16 publications

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“…As discussed in [36], if the standard 3 × 3 neutrino mixing matrix U PMNS would be non-unitary, it should be a part of a larger unitary matrix. Contractions imply that also all matrices from the region Ω can be naturally expanded to a larger unitary matrix.…”

Section: Dilation a Quest For Complete Mixingmentioning

confidence: 99%

See 1 more Smart Citation

New limits on neutrino non-unitary mixings based on prescribed singular values

Flieger

Gluza

Porwit

2020

J. High Energ. Phys.

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Singular values are used to construct physically admissible 3-dimensional mixing matrices characterized as contractions. Depending on the number of singular values strictly less than one, the space of the 3-dimensional mixing matrices can be split into four disjoint subsets, which accordingly corresponds to the minimal number of additional, non-standard neutrinos. We show in numerical analysis that taking into account present experimental precision and fits to different neutrino mass splitting schemes, it is not possible to distinguish, on the level of 3-dimensional mixing matrices, between two and three extra neutrino states. It means that in 3+2 and 3+3 neutrino mixing scenarios, using the so-called α parametrization, ranges of non-standard mixings are the same. However, on the level of a complete unitary 3+1 neutrino mixing matrix, using the dilation procedure and the Cosine-Sine decomposition, we were able to shrink bounds for the "light-heavy" mixing matrix elements. For instance, in the so-called seesaw mass scheme, a new upper limit on |U e4 | is about two times stringent than before and equals 0.021. For all considered mass schemes the lowest bounds are also obtained for all mixings, i.e. |U e4 |, |U µ4 |, |U τ 4 |.

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Section: Dilation a Quest For Complete Mixingmentioning

confidence: 99%

“…In this paper we investigate in detail our original idea [32] on how the notions of singular values and contractions which are coming from the matrix theory, influence limits on neutrino mixing parameters within the standard PMNS mixing matrix framework [33][34][35], when additional neutrino states are added [32,36].…”

Section: Introductionmentioning

confidence: 99%

New limits on neutrino non-unitary mixings based on prescribed singular values

Flieger

Gluza

Porwit

2020

J. High Energ. Phys.

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“…Quantitative results of mixing matrix analysis by singular values can be found in [5,18,19]. In these works, the estimation of allowed space for additional neutrinos is discussed, along with statistical analysis of physically admissible mixing matrices within experimental bounds, and the possibility to distinguish sets in (12).…”

Section: -Dimensional Mixing Basismentioning

confidence: 99%

Studies of Non-standard Particle Mixings Through Singular Values

Flieger¹,

Porwit²,

Gluza³

2019

Acta Phys. Pol. B

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Singular values provide a method to study mixing matrices in particle physics. The methods of unitary dilations and the cosine-sine matrix decomposition are discussed in the framework of the Standard Model neutrinos mixing with one non-standard neutrino. We show that the mixings are continuous functions of singular values. It implies that the magnitude of non-standard mixing can be estimated from below and above unambiguously from the experimentally determined interval PMNS mixing matrix.

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“…Moreover, it is possible to define a set of all physically admissible mixing matrices. On top of that the method of so-called unitary dilation gives us the possibility to study in a systematic way scenarios with additional neutrinos [31].…”

Section: Introductionmentioning

confidence: 99%