Complex sentence: After he has vanished, Superman, Green Lantern and Booster Gold appear in the past via Booster Gold's time sphere, having tracked Bruce to the past, only for Superman to confirm with his super-hearing that Batman isn't in this time.
Split into simpler sentences: After he has vanished, Superman, Green Lantern and Booster Gold appear in the past via Booster Gold's time sphere, having tracked Bruce to the past. Superman confirms with his super-hearing that Batman isn't in this time.