Vector and Axial-Vector Spectral Functions and QCD

Abstract

We present new results of the tau hadronic spectral function analysis using data accumulated by the ALEPH detector at LEP during the years 1991-94. In addition to the vector spectral functions, the axial-vector spectral functions and, separately, the tau --> 3pi nu as well as the tau --> pi 2pi0 nu spectral functions are determined from their respective unfolded, i.e., physical invariant mass spectra. The spectral functions are applied to QCD chiral sum rules in order to extract information about saturation at the tau mass scale. Using the the semi-leptonic tau decay rate for vector and axial-vector currents in addition to spectral moments, we obtain precise measurements of the strong coupling constant alpha_s(M_tau) and the contributing non-perturbative power terms. The evolution to the Z mass yields alpha_s(M_Z) = 0.1219 +/- 0.0019.

15 pages, 12 figures, LaTex, Talk given at the Fourth International Workshop on Tau Lepton Physics (TAU96), Colorado, September 1996

Cited by in corpus (10)

• The Physics of Hadronic Tau Decays
• Calculation of the QED Coupling alpha (M_Z) in the Modified Minimal-Subtraction Scheme
• Constraints on Hadronic Spectral Functions From Continuous Families of Finite Energy Sum Rules
• QCD Sum Rule Determination of $\alpha (M_Z)$ with Minimal Data Input
• Problems With Extracting $m_s$ from Flavor Breaking in Hadronic $\tau$ Decays
• Tau Physics
• Isospin Breaking and the Extraction of $m_s$ from the $\tau$-Decay-Like Vector Current Sum Rule
• Tau Decay Determination of the Strange Quark Mass
• QCD Tests from Tau Decays
• The DMO Sum Rule Revisited