Bonn 2010 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 15: Flavourphysik (Theorie) I
T 15.1: Vortrag
Mittwoch, 17. März 2010, 14:00–14:15, HG XIII
Charm mixing in the framework of HQE — •Markus Bobrowski and Alexander Lenz — Universität Regensburg
In this talk we issue the quark-level analysis of meson-antimeson mixing in the charm system. Although a naïve application of the heavy-quark-expansion (HQE) approach to D0 mesons fails to reproduce the experimental width differences by orders of magnitude, we argue that currently there seem to be no indications for a complete breakdown of HQE-based techniques in the leading dimensions 6 and 7. The smallness of current quark-level based theory predictions can be understood as a result of efficient GIM interference between numerically rather large diagrams; any mechanism, which helps to lift this suppression, could possibly serve as a solution to this problem: This may be new physics modifications of CKM couplings or enhancement of SU(3)F symmetry breaking. Within the Standard Model, GIM lifting is sometimes supposed to come along with the cutting of internal quark loops in dimension 9 and 12 of the HQE. Reliable results for the quark-level expectation could finally provide a test of quark-hadron duality in the charm sector.