Jul 4 – 11, 2012
Melbourne Convention and Exhibition Centre
Australia/Melbourne timezone
ICHEP2012 - 36th International Conference for High Energy Physics

Precision calculation of the Standard Model \Delta S=2 contribution to indirect CP violation in K->\pi\pi decays

Jul 7, 2012, 9:30 AM
Room 220 (Melbourne Convention and Exhibition Centre)

Room 220

Melbourne Convention and Exhibition Centre

Melbourne Australia
Parallel Sessions Track 10. Lattice QCD Room 220 Lattice QCD / B-Physics / CP Violation, etc -TR5&7&10


Dr Thorsten Kurth (Bergische Universität Wuppertal (DE))


Indirect CP violation in K -> pipi decays plays a central role in constraining the flavor structure of the Standard Model and in the search for new physics. For many years the leading uncertainty in the SM prediction of this phenomenon was the one associated with the nonperturbative strong interaction dynamics in this process. I will present a fully nonperturbative lattice QCD calculation of the neutral kaon mixing parameter B_K, which quantifies the bulk of these effects. Our study involves 21 large-scale simulations with up and down quark masses all the way down to their very small physical value. It additionally involves nonperturbative renormalization. That allows us to gain full control over all sources of error and to determine B_K with an overall 1.1% uncertainty in the RI scheme at a scale 3.5 GeV, namely B_K^RI(3.5 GeV)=0.531(6)_stat(2)_sys. I will end the talk with a discussion of the phenomenological implications of our result.

Primary author

Dr Thorsten Kurth (Bergische Universität Wuppertal (DE))


Mr Antonin Portelli (CPT Marseille) Christian Holbling (Unknown) Craig McNeile (University of Glasgow) Dr Kalman Szabo (Bergische Universität Wuppertal) Laurent Lellouch (Centre National de la Recherche Scientifique (CNRS)) Sandor Katz Dr Stefan Krieg (JSC FZ Julich) Stephan Durr (JSC at FZ Juelich and Wuppertal University) Prof. Thomas Lippert (JSC, FZ-Julich) Zoltan Fodor (BUW)

Presentation materials