Study of T violation in K+→π+μ+μ- decays

We study the possibility of observing T violation in the process K+→π+μ+μ-. To this end we define appropriate T-violation indicators. We find that the measurements of the two-spin correlations can provide a reliable test of the Cabibbo-Kobayashi-Maskawa mechanism of T violation. The final-state interactions mainly contribute to indicators involving only one spin. We also estimate the size of the contribution of a representative set of extensions of the standard model to T-violation indicators. We find that their contribution can be important only in models with loosely constrained new parameters