Kaon mixing matrix elements from beyond-the-Standard-Model operators in staggered chiral perturbation theory

Understand

Models of new physics induce K-Kbar mixing operators having Dirac structures other than the "left-left" form of the Standard Model.

• We calculate the functional form of the corresponding B-parameters at next-to-leading order in both SU(3) and SU(2) staggered chiral perturbation theory (SChPT).
• Numerical results for these matrix elements are being generated using improved staggered fermions; our results can be used to extrapolate these matrix elements to the physical light and strange quark masses.
• The SU(3) SChPT results turn out to be much simpler than that for the Standard Model B_K operator, due to the absence of chiral suppression in the new operators.