LATTICE INPUT ON THE INCLUSIVE τ DECAY Vus PUZZLE

Abstract

Recent analyses of flavor-breaking hadronic-τ-decay-based sum rules produce values of |Vus| ~ 3σ low compared to 3-family unitarity expectations. An unresolved systematic issue is the significant variation in |Vus| produced by different prescriptions for treating the slowly converging D = 2 OPE series. We investigate the reliability of these prescriptions using lattice data for various flavor-breaking correlators and show the fixed-scale prescription is clearly preferred. Preliminary updates of the conventional τ-based, and related mixed τ-electroproduction-data-based, sum rule analyses incorporating B-factory results for low-multiplicity strange τ decay mode distributions are then performed. Use of the preferred FOPT D = 2 OPE prescription is shown to significantly reduce the discrepancy between 3-family unitarity expectations and the sum rule results.