+
+ double ap=0;
+
+ {
+ AliKFParticle kf01 = kf1, kf02 = kf2;
+ kf01.SetProductionVertex(v0);
+ kf02.SetProductionVertex(v0);
+ kf01.TransportToProductionVertex();
+ kf02.TransportToProductionVertex();
+ double px1=kf01.GetPx(), py1=kf01.GetPy(), pz1=kf01.GetPz();
+ double px2=kf02.GetPx(), py2=kf02.GetPy(), pz2=kf02.GetPz();
+ double px = px1+px2, py = py1+py2, pz = pz1+pz2;
+ double p = sqrt(px*px+py*py+pz*pz);
+ double l1 = (px*px1 + py*py1 + pz*pz1)/p;
+ double l2 = (px*px2 + py*py2 + pz*pz2)/p;
+ double pt = sqrt(px1*px1+py1*py1+pz1*pz1 - l1*l1);
+ ap = (l1-l2)/(l1+l2);