Power corrections to alpha_s(M_τ),|V_{us}| and m_s

Simple item page
dc.creatorNarison, Stephan
dc.date2009-01-26
dc.date2009-02-02
dc.date.accessioned2026-07-07T13:01:06Z
dc.date.available2026-07-07T13:01:06Z
dc.descriptionWe re-examine recent determinations of power corrections from tau-decay and confront the results with the existing ones from QCD spectral sum rules (QSSR). We conclude that contrary to the QSSR analysis, which lead to <alpha_s G^2>=(6.8+-1.3)10^{-2} GeV^4, tau-decay is not a good place for extracting the gluon condensate due to its extra alpha_s^2 coefficient which suppresses its contribution in this process. Results from e^+e^- sum rules and tau-decay: rho alpha_s<uu>^2= (4.5+-0.3)10^{-4}GeV^6, where rho=3.0+-0.2 confirm the deviation from the vacuum saturation estimate of the four-quark condensate."Non-standard" power corrections (direct instantons, duality violation and tachyonic gluon mass) beyond the SVZ-expansion, partially cancel out in the V+A hadronic tau-decay channel, which gives at order alpha_s^4: alpha_s(M_tau)=0.3249(29)_{ex}(75)_{th} leading to als(M_Z)|_tau=0.1192 (4)_{ex}(9)_{th},in remarkable agreement with (but more accurate than) alpha_s(M_Z)|_Z=0.1191(27)obtained at the same alpha_s^4 order from the Z-width and the global fit of electroweak data. Finally, the role of the tachyonic gluon mass in the determinations of |V_{us}|from tau-decay and of m_s from tau-decay, e^+e^- and (pseudo)scalar channels is emphasized.
dc.descriptionVersion to appear in PLB
dc.identifierhttps://arxiv.org/abs/0901.3823
dc.identifierhttp://arxiv.org/abs/0901.3823
dc.identifierPhys.Lett.B673:30-36,2009
dc.identifierdoi:10.1016/j.physletb.2009.01.062
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/226051
dc.subjectHigh Energy Physics - Phenomenology
dc.subjectHigh Energy Physics - Experiment
dc.subjectHigh Energy Physics - Lattice
dc.titlePower corrections to alpha_s(M_τ),|V_{us}| and m_s
dc.typetext

Files

Collections

arXiv