Effects of possible extensions to rapidity coverage of the ATLAS detector on the determination of sin^2Theta_eff(M^2_Z).

ATLAS forward calorimeter offers a possibility of identifying electrons in the forward region, 2.5<|y_e|<4.9. Extending the standardZ forward-backward asymmetry analysis, in which both electrons are required to be within |y_e|<2.5, by allowing one electron in the forward region while keeping the other one within |y_e|<2.5, makes it possible to measure the sin^2Theta_W with an statistical error of 1.4x10^(-1). Results are very encouraging, as such precision is betterthan that obtained with LEP. Further studies of systematic errors willhave to follow to be able to reduce those errors to the required level. It seems that, although difficult, it might be possible to achieve.