Universal Unitarity Triangle 2016 and the tension between ΔMs,d and εK in CMFV models

Monika Blanke, Andrzej J. Buras

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47 Scopus citations

Abstract

Motivated by the recently improved results from the Fermilab Lattice and MILC Collaborations on the hadronic matrix elements entering (Formula presented.) in (Formula presented.) – (Formula presented.) mixing, we determine the universal unitarity triangle (UUT) in models with constrained minimal flavour violation (CMFV). Of particular importance are the very precise determinations of the ratio (Formula presented.) and of the angle (Formula presented.). They follow in this framework from the experimental values of (Formula presented.) and of the CP-asymmetry (Formula presented.). As in CMFV models the new contributions to meson mixings can be described by a single flavour-universal variable S(v), we next determine the CKM matrix elements (Formula presented.) , (Formula presented.) , (Formula presented.) and (Formula presented.) as functions of S(v) using the experimental value of (Formula presented.) as input. The lower bound on S(v) in these models, derived by us in 2006, implies then upper bounds on these four CKM elements and on the CP-violating parameter (Formula presented.) , which turns out to be significantly below its experimental value. This strategy avoids the use of tree-level determinations of (Formula presented.) and (Formula presented.) , which are presently subject to considerable uncertainties. On the other hand, if (Formula presented.) is used instead of (Formula presented.) as input, (Formula presented.) are found to be significantly above the data. In this manner we point out that the new lattice data have significantly sharpened the tension between (Formula presented.) and (Formula presented.) within the CMFV framework. This implies the presence of new physics contributions beyond this framework that are responsible for the breakdown of the flavour universality of the function S(v). We also present the implications of these results for (Formula presented.) , (Formula presented.) and (Formula presented.) within the Standard Model.

Original languageEnglish
Article number197
JournalEuropean Physical Journal C
Volume76
Issue number4
DOIs
StatePublished - 1 Apr 2016

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