The lepton angular distribution coefficients $A_i$ for $Z$ boson production in $pp$ and $bar p p$ collisions have been measured at the LHC and the Tevatron. A recent study showed that many features of the measured angular distribution coefficients, including the transverse momentum ($q_T$) and rapidity dependencies and the violation of the Lam-Tung relation, can be well described using an intuitive geometric approach. In this paper, we extend this geometric approach to describe the angular distribution coefficients for $W$ boson produced in $bar{p} p$ collisions at the Tevatron. We first compare the data with a perturbative QCD calculation at $mathcal{O}(alpha_s^2)$. We then show that the data and QCD calculations can be well described with the geometric approach. Implications for future studies at the LHC energy are also discussed.
تحميل البحث