And I want to align the betas on the right, and the argument(QED,ED,QD) on the left. Currently I use brackets only.
Any clue on how to do it?
Here's a way in Word 2007; later versions should work similarly. This is for the new-style equation editor, which I believe is what you're using since your screenshot is in the Cambria Math font.
The result will be:
The final result: