Neutrino masses and mixing: singular mass matrices and quark–lepton symmetry

Doršner, Ilja; Smirnov, A. Yu.

doi:10.1016/j.nuclphysb.2004.07.028

Cited by 22 publications

(46 citation statements)

References 45 publications

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“…If the deviation D 23 is significant, we cannot speak of a special symmetry. Indeed, the large 2 -3 mixing may appear simply as the sum of small (order of Cabibbo) mixing angles (see, e.g., [7]). So, maximal or nonmaximal mixing is equivalent to the dilemma of new symmetry or no new symmetry of nature.…”

Section: Introductionmentioning

confidence: 99%

Measuring the deviation of the 2–3 lepton mixing from maximal with atmospheric neutrinos

2004

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The measurement of the deviation of the 2 -3 leptonic mixing from maximal, D 23 1=2 ÿ sin 2 23 , is one of the key issues for understanding the origin of the neutrino masses and mixing. In the 3 context we study the dependence of various observables in the atmospheric neutrinos on D 23 . We perform the global 3-analysis of the atmospheric and reactor neutrino data taking into account the effects of both the oscillations driven by the solar parameters (m 2 21 and 12 ) and the 1-3 mixing. The departure from the one-dominant mass scale approximation results into the shift of the 2 -3 mixing from maximal by sin 2 23 0:04, so that D 23 0:04 0:07 1. Though the value of the shift is not statistically significant, the tendency of the allowed region to move towards smaller values of sin 2 23 is robust. The shift is induced by the excess of the e-like events in the sub-GeV sample. We show that future large scale water Cherenkov detectors can determine D 23 with accuracy of a few percent, comparable with the sensitivity of future long-baseline experiments. Moreover, the atmospheric neutrinos will provide unique information on the sign of the deviation (octant of 23 ).

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Section: Introductionmentioning

confidence: 99%

Measuring the deviation of the 2–3 lepton mixing from maximal with atmospheric neutrinos

2004

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“…[7]. Instead of democratic mass matrices, the starting point is a singular matrix of the form 2 ; ; 1 T 2 ; ; 1.…”

Section: Introductionmentioning

confidence: 99%

Neutrino masses and mixing, quark-lepton symmetry, and strong right-handed neutrino hierarchy

Dermíšek

2004

Phys. Rev. D

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Assuming the same form of all mass matrices as motivated by quark-lepton symmetry, we discuss conditions under which bilarge mixing in the lepton sector can be obtained with a minimal amount of fine-tuning requirements for possible models. We assume hierarchical mass matrices, dominated by the 3-3 element, with off-diagonal elements much smaller than the larger neighboring diagonal element. Characteristic features of this scenario are strong hierarchy in masses of right-handed neutrinos, and comparable contributions of both lighter right-handed neutrinos to the resulting left-handed neutrino Majorana mass matrix. Because of obvious quark-lepton symmetry, this approach can be embedded into grand unified theories. The mass of the lightest neutrino does not depend on details of a model in the leading order. The right-handed neutrino scale can be identified with the GUT scale in which case the mass of the lightest neutrino is given as m 2 top =M GUT jU 1 j 2 .

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“…Two of the three mixing angles 12 ; 23 ; 13 commonly used to parametrize the lepton mixing matrix are large: The ''solar'' mixing angle 12 is approximately 33 , where maximal mixing is excluded at more than 5 [1]. The best-fit value of the ''atmospheric'' mixing angle 23 is very close to maximal mixing [2], where current data are still consistent with rather large deviations from maximality: At 3 the allowed range is 0:31 sin 2 23 0:72 [1]. These results are in sharp contrast to the quark sector, where generation mixing is small.…”

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confidence: 99%