An Approach to Extract the Spin Transfer to ∧in Polarized Proton--Proton Collision

We introduce an approach to extract the spin transfer to ∧ in polarized proton--proton collision, based on the relation between single spin asymmetry and the polarization of ∧ production. With 4×10⁶ ∧ events simulated for a PHENIX detector system, D_LL = 0.1598 \pm 0.0343 is retrieved by the approach and it agrees very well with the input value of 0.1429. The approach is further tested and confirmed with `bunch shuffling' method for the simulated events as well as experimental events collected at PHENIX in 2003. It is concluded that one can correctly extract the spin transfer without detailed understanding of acceptance correction even if the correction is significantly large in PHENIX experiment by using the approach described here. The method can be generally used for spin transfer study.