The final SLD results for ALR and Alepton

TL;DR

This paper reports the final measurements of Z boson production asymmetries and lepton coupling parameters from polarized e+e- collisions, providing precise tests of the Standard Model and implications for the Higgs boson mass.

Contribution

It presents the complete set of measurements of ALR and lepton coupling asymmetries at SLD, with improved precision and combined results, enhancing tests of electroweak theory.

Findings

Measured ALR = 0.15056 ± 0.00239

Combined lepton asymmetry parameter Ae = 0.1516 ± 0.0021

Effective weak mixing angle sin^2 θ_eff_W = 0.23098 ± 0.00026

Abstract

We present the final measurements of the left-right cross-section asymmetry (ALR) for Z boson production by e+e- collisions and Z boson-lepton coupling asymmetry parameters Ae, Amu, and Atau in leptonic Z decays with the SLD detector at the SLAC Linear Collider. Using the complete sample of polarized Z bosons collected at SLD, we get ALR = 0.15056 +- 0.00239, Ae = 0.1544 +- 0.0060, Amu = 0.142 +- 0.015, and Atau = 0.136 +- 0.015. The ALR=Ae and Ae results are combined and we find Ae = 0.1516 +- 0.0021. Assuming lepton universality, we obtain a combined effective weak mixing angle of sin 2 theta eff W = 0.23098 +- 0.00026. Within the context of the SM, our result prefers a light Higgs mass.