Angular Coefficients Measurement of Drell-Yan Dielectron Pairs at CDF

We report on the measurement of the angular distributions of final state electrons in $p\bar{p} \rightarrow \gamma^*/Z \rightarrow e^+e$ events produced in the $Z$ boson region mass range of 66 to 116 GeV/c2 from 2.1 $fb^{-1}$ of proton anti-proton collisions at $\sqrt{s} = 1.96$ TeV taken by the CDF detector at Fermilab. The transverse momentum ($P_T$) dependent angular coefficients A0, A2, A3, and A4 are compared with several predictions based on Quantum Chromodymnamics (QCD). The $P_T$ dependence of A0 and A2 is in agreement with the predictions of perturbative QCD and shows that the production of $Z$ bosons at large $P_T$ proceeds via a combination of the quark-antiquark annihilation and the quark-gluon Compton processes. We find a good agreement with the Lam-Tung relation (A0 = A2), which implies that the spin of the gluon is 1.