1301.4930 (P. A. Boyle et al.)

New results from the lattice on the theoretical inputs to the hadronic
tau determination of V_us    [PDF]

P. A. Boyle, L. Del Debbio, N. Garron, R. J. Hudspith, E. Kerrane, K. Maltman, J. M. Zanotti

Recent sum rule determinations of |V_us|, employing flavor-breaking combinations of hadronic tau decay data, are significantly lower than either expectations based on 3-family unitarity or determinations from K_ell3 and Gamma[K_mu2]/Gamma[pi_mu2]. We use lattice data to investigate the accuracy/reliability of the OPE representation of the flavor-breaking correlator combination entering the tau decay analyses. The behavior of an alternate correlator combination, constructed to reduce problems associated with the slow convergence of the D = 2 OPE series, and entering an alternate sum rule requiring both electroproduction cross-section and hadronic tau decay data, is also investigated. Preliminary updates of both analyses, with the lessons learned from the lattice data in mind, are also presented.

View original: http://arxiv.org/abs/1301.4930