  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.
