# Measurement of the parity-violating longitudinal single-spin asymmetry for $W^{\pm}$ boson production in polarized proton-proton collisions at $\sqrt{s} = 500$GeV

Abstract : We report the first measurement of the parity violating single-spin asymmetries for midrapidity decay positrons and electrons from $W^{+}$ and $W^{-}$ boson production in longitudinally polarized proton-proton collisions at $\sqrt{s}=500$GeV by the STAR experiment at RHIC. The measured asymmetries, $A^{W^+}_{L}=-0.27\pm 0.10\;({\rm stat.})\pm 0.02\;({\rm syst.}) \pm 0.03\;({\rm norm.})$ and $A^{W^-}_{L}=0.14\pm 0.19\;({\rm stat.})\pm 0.02 \;({\rm syst.})\pm 0.01\;({\rm norm.})$, are consistent with theory predictions, which are large and of opposite sign. These predictions are based on polarized quark and antiquark distribution functions constrained by polarized DIS measurements.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00517035
Contributor : Dominique Girod <>
Submitted on : Monday, September 13, 2010 - 2:06:23 PM
Last modification on : Friday, November 27, 2020 - 10:46:03 PM

### Citation

M.M. Aggarwal, Z. Ahammed, A.V. Alakhverdyants, I. Alekseev, J. Alford, et al.. Measurement of the parity-violating longitudinal single-spin asymmetry for $W^{\pm}$ boson production in polarized proton-proton collisions at $\sqrt{s} = 500$GeV. Physical Review Letters, American Physical Society, 2011, 106, pp.062002. ⟨10.1103/PhysRevLett.106.062002⟩. ⟨in2p3-00517035⟩

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