Measuring polarization of light quarks at ATLAS and CMS

Polarization of strange quarks is preserved to a high degree when they hadronize into Λ baryons, as observed in Z decays at LEP. This opens up the possibility for ATLAS and CMS to use strange-quark polarization measurements as a characterization tool for new physics scenarios that produce such quarks. Measurements in tt¯ samples would be useful for obtaining additional information about the polarization transfer from the strange quark to the Λ baryon. Already with 100fb-1 in run 2, tt¯ samples in ATLAS and CMS become competitive in sensitivity with the Z samples of the LEP experiments. Moreover, while the LEP measurements were done inclusively over all quark flavors, which makes their interpretation dependent on various modeling assumptions, tt¯ events at the LHC offer multiple handles for disentangling the different contributions experimentally. We also discuss the possibility of measuring polarizations of up and down quarks.