A mixed τ-electroproduction sum rule for |Vus

• Published in: Physics letters. B Vol. 672; no. 3; pp. 257 - 263
• Main Author: Maltman, K.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 23.02.2009
• Subjects: 13.35.Dx; 11.55.Hx; 12.15.Hh
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/j.physletb.2009.01.036

The interpretation of results of recent τ decay determinations of |Vus|, which yield values ∼3σ low compared to 3-family unitarity expectations, is complicated by the slow convergence of the relevant integrated D=2 OPE series. We introduce a class of new sum rules involving both electroproduction and τ decay data designed to deal with this problem by strongly suppressing D=2 OPE contributions at the correlator level. Experimental complications are briefly discussed and an example of the improved control over theoretical errors presented. The uncertainty on the resulting determination, |Vus|=0.2202(39), is entirely dominated by experimental errors, and should be subject to significant near-term improvement.