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Abstract |
The consistent matching of short-distance contributions and hadronic matrix elements is crucial for precise predictions of weak processes involving hadrons. In this Letter, we address this point for chargedcurrent processes involving two pions-pion beta decay pi(+/-) -* pi(0) e(+/-)nu(e) and hadronic tau decays tau(+/-) – pi(+/-)pi(0)nu(tau)- whose decay rates depend on the so-called gamma W box correction. Using recent results from lattice QCD, we show how to formulate the matching beyond leading-logarithmic accuracy, in particular, how to cancel the dependence on the scheme choice for evanescent operators. As main results, we obtain a prediction for the decay rate of pion beta decay with theory uncertainties improved by a factor of 3, which renders theory uncertainties negligible for future determinations of V-ud even beyond the reach of the PIONEER experiment, and an evaluation of isospin-breaking corrections to tau -> pi pi nu(tau) with negligible uncertainty from the short-distance matching, as necessary for a future tau-based determination of the hadronic-vacuumpolarization contribution to the anomalous magnetic moment of the muon. |
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Address |
[Cirigliano, Vincenzo; Valori, Nicola] Univ Washington, Inst Nucl Theory, Seattle, WA 91195 USA; [Hoferichter, Martin] Univ Bern, Inst Theoret Phys, Albert Einstein Ctr Fundamental Phys, Sidlerstr 5, CH-3012 Bern, Switzerland; [Valori, Nicola] Univ Valencia, Inst Fis Corpuscular, Edificio Inst Invest,C Catedrat Jose Beltran 2, Paterna 46980, Spain; [Valori, Nicola] CSIC, Edificio Inst Invest,C Catedrat Jose Beltran 2, Paterna 46980, Spain |
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