Blanke M, Buras AJ. Universal Unitarity Triangle 2016 and the tension between [Formula: see text] and [Formula: see text] in CMFV models.
THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS 2016;
76:197. [PMID:
28260971 PMCID:
PMC5312165 DOI:
10.1140/epjc/s10052-016-4044-6]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 03/28/2016] [Indexed: 06/06/2023]
Abstract
Motivated by the recently improved results from the Fermilab Lattice and MILC Collaborations on the hadronic matrix elements entering [Formula: see text] in [Formula: see text]-[Formula: see text] 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: see text] and of the angle [Formula: see text]. They follow in this framework from the experimental values of [Formula: see text] and of the CP-asymmetry [Formula: see text]. 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: see text], [Formula: see text], [Formula: see text] and [Formula: see text] as functions of S(v) using the experimental value of [Formula: see text] 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: see text], which turns out to be significantly below its experimental value. This strategy avoids the use of tree-level determinations of [Formula: see text] and [Formula: see text], which are presently subject to considerable uncertainties. On the other hand, if [Formula: see text] is used instead of [Formula: see text] as input, [Formula: see text] 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: see text] and [Formula: see text] 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: see text], [Formula: see text] and [Formula: see text] within the Standard Model.
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