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arXiv · 0904.3014

Is the Unitarity Triangle Right?

P. F. Harrison·D. R. J. Roythorne·W. G. Scott
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Abstract

The latest fits to the CKM matrix indicate that alpha=(90.7+4.5-2.9) degrees. The proximity of alpha to a right-angle raises the question: is it merely accidental or is it due to some physics beyond the Standard Model? In the framework of our recently-proposed flavour permutation symmetry, we consider the similarities between the quark and lepton mixing matrices, V and U, arguing that the relative smallness of one element in each suggests common constraints. These constraints link the smallness of V_ub and U_e3 with each other, and with the approximate mu-tau symmetry observed in leptonic mixing, together with a prediction of a large Dirac CP phase in both the quark and lepton sectors. In the quark case, we predict alpha=(89.0\pm 0.2) degrees, in agreement with data and suggesting that the unitarity triangle is in fact very nearly, but not exactly right.

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P. F. Harrison, D. R. J. Roythorne, W. G. Scott. 2009-04-20. Is the Unitarity Triangle Right?. https://arxiv.org/abs/0904.3014

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