Measurement of Longitudinal Spin Asymmetries From $W\to e$ Boson Decay in Polarized pp Collisions at $\sqrt{s}=500$ GeV at RHIC-PHENIX

We report the measurement of the parity violating single spin asymmetries for inclusive high transverse momentum electrons and positrons in polarized $p+p$ collisions at a center of mass energy of $\sqrt{s}=500$ GeV with the PHENIX detector at RHIC. These electrons are attributed to the decay of $W^{\pm }$ and $Z^0$ bosons, and measured production cross section is consistent with the expectations. The $W$ production is confirmed for the first time in $p+p$ collisions. Its spin asymmetry in the polarized $p+p$ collisions is a important probe for the quark flavor decomposition of the proton spin.