Measurement of $\Lambda$ hyperon spin-spin correlations in p+p collisions by the STAR experiment

Abstract

Polarization of $\Lambda$ hyperons has been observed in various collision systems over a wide range of collision energies over the last 50 years since its discovery in Fermilab in the 70's. The existing experimental and theoretical techniques were not able to provide a conclusive answer about the origin of the polarization. In these proceedings, we discuss the possibility to use a new experimental method which utilizes measurement of $\Lambda\bar{\Lambda}$, $\Lambda\Lambda$, and $\bar{\Lambda}\bar{\Lambda}$ pair spin-spin correlations. With this new approach, it should be possible to distinguish if the polarization originates from early stage effects, such as initial state parton spin correlation, or if it is a final state effect originating from hadronization. Furthermore we, study the feasibility to perform this measurement in $p+p$ collisions at $\sqrt{s} = 200$~GeV collected by STAR in 2012 which should provide sufficient statistics of $\Lambda\bar{\Lambda}$, $\Lambda\Lambda$, and $\bar{\Lambda}\bar{\Lambda}$ pairs to perform this measurement.