QCD Studies at LEP I

TL;DR

This paper reports on QCD studies at LEP I, measuring the strong coupling constant, testing flavor independence, and observing quark-gluon jet differences, utilizing high-statistics hadronic events and silicon vertex detectors.

Contribution

It provides precise measurements of $ alpha_s$, tests flavor independence, and observes quark-gluon jet differences at LEP I, advancing understanding of QCD dynamics.

Findings

Measured $ alpha_s(M_Z) = 0.122 \\pm 0.004$

Confirmed flavor independence of $ alpha_s$ within uncertainties

Observed quark-gluon jet multiplicity ratio of 1.234 \\pm 0.027

Abstract

The high hadronic event statistics collected at the Z energy (LEP I) allowed a good understanding of the QCD dynamics. The coupling constant $\alpha_s$ has been measured with several methods giving a global average $\alpha_s(M_Z) = 0.122 \pm 0.004$. The flavour independence of $\alpha_s$ has been tested obtaining $\alpha_s^b/\alpha_s^{udsc} = 0.997 \pm 0.023$. Quark-gluon jet differencies has been observed among which $<n>_{gluon}/<n>_{quark} = 1.234 \pm 0.027$. A big role has been plaied by the silicon vertex detectors.