title: K(L) - K(S) mass difference from lattice QCD.
abstract: We report on the first complete calculation of the K_{L}-K_{S} mass difference, ΔM_{K}, using lattice QCD. The calculation is performed on a 2+1 flavor, domain wall fermion ensemble with a 330 MeV pion mass and a 575 MeV kaon mass. We use a quenched charm quark with a 949 MeV mass to implement Glashow-Iliopoulos-Maiani cancellation. For these heavier-than-physical particle masses, we obtain ΔM_{K}=3.19(41)(96)×10^{-12}  MeV, quite similar to the experimental value. Here the first error is statistical, and the second is an estimate of the systematic discretization error. An interesting aspect of this calculation is the importance of the disconnected diagrams, a dramatic failure of the Okubo-Zweig-Iizuka rule.
authors.affiliation: Physics Department, Columbia University, New York, New York 10027, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Bai
authors.affiliation: Physics Department, Columbia University, New York, New York 10027, USA.
authors.forename: N H
authors.initials: NH
authors.lastname: Christ
authors.affiliation: Brookhaven National Laboratory, Upton, New York 11973, USA and RIKEN-BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: T
authors.initials: T
authors.lastname: Izubuchi
authors.affiliation: School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, United Kingdom.
authors.forename: C T
authors.initials: CT
authors.lastname: Sachrajda
authors.affiliation: Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: A
authors.initials: A
authors.lastname: Soni
authors.affiliation: Physics Department, Columbia University, New York, New York 10027, USA.
authors.forename: J
authors.initials: J
authors.lastname: Yu