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Initial attempts to measure the Sivers asymmetry for sea quark Sivers have been reported by the STAR collaboration at RHIC using W/Z boson production. Their data is statistically limited and favor a sign-change only, if TMD evolutions effects are significantly smaller than expected. Star publication: https://arxiv.org/pdf/1511.06003.pdf and study of the sign change of the Sivers function https://arxiv.org/pdf/1612.06413.pdf
SpinQuest will perform the first measurement of the Sivers asymmetry in Drell-Yan pp scattering from the sea quarks.
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