Determination of alpha_S using hadronic event shape distributions of data taken with the OPAL detector

TL;DR

This paper measures the strong coupling constant alpha_S using hadronic event shape data from the OPAL detector, comparing experimental results with advanced theoretical calculations to test QCD predictions.

Contribution

It provides a precise determination of alpha_S at the Z boson mass scale using NNLO and NNLO+NLLA theoretical frameworks, confirming consistency with the world average.

Findings

Alpha_S(MZ)=0.1201+-0.0028 (total uncertainty) with NNLO

Alpha_S(MZ)=0.1189+-0.0036 (total uncertainty) with NNLO+NLLA

Results agree with the world average value of alpha_S.

Abstract

The measurement of the strong coupling alpha_S using hadronic event shape distributions measured with the OPAL detector at center-of-mass energies between 91 and 209 GeV is summarized. For this measurement hadronic event shape distributions are compared to theoretical predictions based on next-to-next-to-leading-calculations (NNLO) and NNLO combined with resummed next-to-leading-logarithm calculations (NLLA). The combined result using NNLO calculations is alpha_S(MZ)=0.1201+-0.0008(stat.)+-0.0013(exp.)+-0.0010(had.)+-0.0024(theo.) and the result using NLLO and NLLA calculations is alpha_S(MZ)=0.1189+-0.0008(stat.)+-0.0016(exp.)=-0.0010(had.)+-0.0036(theo.), with both measurements being in agreement with the world average.