Polarization of anti-lambda in √s=200GeV polarized proton-proton collision

We study the polarization of produced (Lambda) over bar root s=200GeV polarized proton-proton collision at RHIC/PHENIX, and also the polarization as a function of its rapidity which may be sensitivity to the quark helicity distributions of the proton and to the polarized fragmentation functions of the quark into the baryon. For polarized data collected in 2003 a very clean (Lambda) over bar peak in (p) over bar pi(+) invariant mass spectrum in the mid-rapidity(vertical bar eta vertical bar < 0.35) is obtained. In this letter, we report the calculation process of P-(Lambda) over bar as extracted from the data.