We present the first direct measurement of As, the parity-violating coupling of the Z0 boson to the strange quark, using ∼550 000 e+e−→Z0→hadrons events recorded by the SLC Large Detector with a polarized e− beam. We tagged Z0→ss¯ events by the absence of B or D hadrons and the presence in each hemisphere of a high momentum K± or Ks0. Fitting the polar angle distributions of the strangeness-signed thrust axis gave As=0.895±0.066(stat)±0.062(syst). The analyzing power and uu¯+dd¯ background were constrained using the data, greatly reducing any model dependence.
ASJC Scopus subject areas
- Physics and Astronomy(all)