Kaon mixing matrix elements from beyond-the-standard-model operators in staggered chiral perturbation theory

Semileptonic Kaon Decay in Staggered Chiral Perturbation Theory

Abstract The determination of |Vus| from kaon semileptonic decays requires the value of the form factor f+(q 2 = 0), which can be calculated precisely on the lattice. We provide the one-loop partially quenched staggered chiral perturbation theory expressions that may be employed to analyze staggered simulations of f+(q 2) with three light flavors. We consider both the case of a mixed action, wh...

Pion and Kaon masses in Staggered Chiral Perturbation Theory

Abstract We show how to compute chiral logarithms that take into account both theO(a2) taste-symmetry breaking of staggered fermions and the fourth-root trick that produces one taste per flavor. The calculation starts from the Lee-Sharpe Lagrangian generalized to multiple flavors. An error in a previous treatment by one of us is explained and corrected. The one loop chiral logarithm corrections...

Chiral Perturbation Theory and Weak Matrix Elements

I describe recent developments in quenched chiral perturbation theory (QChPT) and the status of weak matrix elements involving light quarks. I illustrate how, with improved statistical errors, and with calculations of the masses of baryons containing non-degenerate quarks, there is now a clear need for extrapolations of higher order than linear in the quark mass. I describe how QChPT makes pred...

Neutral kaon mixing beyond the standard model with nf = 2 + 1 chiral fermions

Kaon Polarizabilities in Chiral Perturbation Theory

We study the kaon polarizabilities in the framework of Chiral Perturbation Theory to order p4. For the neutral kaon we find that them vanish and they have the first non-zero contribution to order p6. We also emphasize the theoretical potential of an eventual measurement of the kaon polarizabilities, in particular of the neutral kaon ones. PACS numbers: 14.40.Aq, 13.40.Gp, 13.60.Fz, 12.39.Fe