A High-Precision Measurement of the Left-Right Z Boson Cross-Section Asymmetry

TL;DR

This paper reports a high-precision measurement of the left-right asymmetry in Z boson production from electron-positron collisions, refining the determination of the weak mixing angle with data from the SLD detector at SLAC.

Contribution

It provides the most precise measurement of the Z boson asymmetry and weak mixing angle using data from 1996-1998, improving previous results.

Findings

Measured ALR0 as 0.15056±0.00239

Determined sin²θ_eff as 0.23107±0.00030

Combined dataset yields sin²θ_eff of 0.23097±0.00027

Abstract

We present a measurement of the left-right cross-section asymmetry (ALR) for Z boson production by e+e- collisions. The measurement includes the final data taken with the SLD detector at the SLAC Linear Collider (SLC) during the period 1996-1998. Using a sample of 383,487 Z decays collected during the 1996-1998 runs we measure the pole-value of the asymmetry, ALR0, to be 0.15056+-0.00239 which is equivalent to an effective weak mixing angle of sin2th(eff) = 0.23107+-0.00030. Our result for the complete 1992-1998 dataset comprising 537 thousand Z decays is sin2th(eff) = 0.23097+-0.00027.