Charm mixing in the Standard Model

Bobrowski, Markus; Lenz, Alexander

Charm mixing in the Standard Model

Bobrowski, Markus; Lenz, Alexander

Authors

Markus Bobrowski

Alexander Lenz

Abstract

In this talk we report on a study on the mixing of neutral charmed mesons and argue that, at the present stage, a CP violating weak phase of the order of some per mille can not be excluded in the Standard Model. It is shown how some, seemingly reasonable, simplifying assumptions about CKM couplings lead to the wrong conclusion that CP violation of this amount is an unambiguous indication of new physics. The presented results rely on a recent short-distance analysis of the ∆C = 2 transition, which con- firms the expectation that the dominant contribution is due to effects of flavour symmetry breaking appearing in higher orders of the Heavy Quark Expansion. We investigate meson-antimeson transitions with an intermediate state coupling to the meson’s sea quark background, present in dimension 10 and 12, using a factorisation approach to simplify the operator basis. On account of a lifting of GIM suppression by one power of ms/mc, the contribution to y = ∆Γ/2Γ is found to exceed that of the formally leading dimension six by a factor close to ten.

Citation

Bobrowski, M., & Lenz, A. (2010). Charm mixing in the Standard Model.

Publication Date	Jan 1, 2010
Deposit Date	Mar 15, 2013
Publicly Available Date	Mar 18, 2015
Volume	ICHEP2010
Series ISSN	1824-8039
Publisher URL	http://arxiv.org/abs/arXiv:1009.4545