First direct measurement of the parity violating coupling of the Z0 to the s quark

We have made the first direct measurement of the parity-violating coupling of the Z^0 boson to the strange quark, A_s, using ~550,000 e^+e^- ->Z^0->hadrons events produced with a polarized electron beam and recorded by the SLD experiment. Z^0 -> s-sbar events were tagged by the absence of B or D hadrons and the presence in each hemisphere of a high-momentum K^+- or K^0_s. From the polar angle distributions of the strangeness-signed thrust axis, we obtained A_s=0.895+-0.066(stat.)+-0.062(syst.). The analyzing power and u-ubar plus d-dbar background were constrained using the data.

Note:

10 pages, 1 figure. Submitted to Physical Review Letters

electron positron: colliding beams
electron positron: annihilation
electron: polarized beam
Z0: electroproduction
Z0: hadronic decay
quark: strangeness
quark: pair production
particle identification: strangeness
angular distribution
Z0: branching ratio

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