# The 16th International Workshop on Tau Lepton Physics (TAU2021) (Virtual Edition)

September 27, 2021 to October 1, 2021
Indiana University
America/Indiana/Indianapolis timezone

## The strong coupling from an improved tau vector isovector spectral function

Sep 29, 2021, 11:20 AM
20m
Virtual (Indiana University)

### Virtual

#### Indiana University

Oral contribution Tau2021 Abstracts

### Speaker

Diogo Boito (Universidade de São Paulo)

### Description

We use a new, more precise, non-strange, inclusive vector
isovector spectral function to determine the strong coupling at the
tau mass scale employing finite energy sum rules. The new spectral
function is obtained from a combination of (i) ALEPH and OPAL results
for the 2 pion and 4 pion tau decay channels, (ii) recent BaBar
results for the tau K Kbar decay distribution, and (iii)
estimates of the contributions from other hadronic tau decay modes
from recent electroproduction data, related using CVC, for subleading
contributions. This new inclusive spectral function is fully data
based and does not rely on Monte Carlo simulated data. Using the
fixed-order perturbation theory (FOPT) prescription, we find for the
strong coupling at the tau mass the value 0.3077(75), which
corresponds to the five-flavor result 0.1171(10) at the Z mass.
Additional experimental input on the dominant 2 pion and 4 pion tau
decay modes would allow for further improvements to the current
analysis.