6533b7ddfe1ef96bd127510b

RESEARCH PRODUCT

From Hadronic τ Decays to the Chiral Couplings and

Antonio PichJoaquim PradesMartín González-alonso

subject

Quantum chromodynamicsPhysicsNuclear and High Energy PhysicsParticle physicsChiral perturbation theoryHadronOrder (group theory)Sum rule in quantum mechanicsAtomic and Molecular Physics and Optics

description

A sum rule analysis of the hadronic τ -decay data can be used to determine the low-energy constants L 10 r ( μ ) and C 87 r ( μ ) . These constants are QCD chiral-order parameters, which appear at order p 4 and p 6 , respectively, in the chiral perturbation theory expansion of the V − A correlator. At order p 4 we obtain L 10 r ( M ρ ) = − ( 5.22 ± 0.06 ) ⋅ 10 − 3 . Including in the analysis the order p 6 contributions, we get L 10 r ( M ρ ) = − ( 4.06 ± 0.39 ) ⋅ 10 − 3 and C 87 r ( M ρ ) = ( 4.89 ± 0.19 ) ⋅ 10 − 3 GeV − 2 .

https://doi.org/10.1016/j.nuclphysbps.2009.03.017