Identified Hadron Production and Light Quark Fragmentation in Z0 Decays

TL;DR

This study measures hadron production rates and light quark fragmentation in Z0 decays, revealing flavor dependencies and testing fragmentation models, while also directly measuring the parity-violating coupling of Z0 to strange quarks.

Contribution

It provides detailed measurements of hadron production in flavor-tagged Z0 decays and a direct measurement of the strange quark coupling, comparing results with fragmentation models.

Findings

Flavor dependence observed in hadron production

Measured parity-violating coupling A_s = 0.82 ± 0.10 (stat) ± 0.07 (syst)

Results compared with three fragmentation models

Abstract

We have measured the differential cross sections for the production of $\pi^{+}$, $K^{+}$, $K^{0}$, $K^{*0}$, $\phi$, p, $\Lambda$ and their corresponding antiparticles in separate samples of flavor-tagged $Z^{0}\to$ light-flavor ($u\bar{u}$, $d\bar{d}$, or $s\bar{s}$), $Z^{0}\to c\bar{c}$ and $Z^{0}\to b\bar{b}$ events. Clear flavor dependences are observed, and the results are compared with the predictions of three fragmentation models. We have also performed a direct measurement of $A_{s}$, the parity-violating coupling of the $Z^{0}$ to strange quarks, by measuring the left-right-forward-backward production asymmetry in polar angle of the tagged $s$ quark. Our preliminary result is $A_{s}$ = $0.82\pm 0.10(stat.)\pm 0.07(syst.)$.