  We report on a precision measurement of the effective weak mixing angle using
the forward-backward asymmetry, $A_{FB}$, in Drell-Yan ($ee$ and $\mu\mu$)
events in pp collisions at $\sqrt{s}=8~\mathrm{TeV}$ at the CMS experiment at
the Large Hadron Collider (LHC). The results are compared to other hadron
collider measurements published by ATLAS, LHCb, CDF, D0 and Tevatron
combination.
