Performance and Strategies of the b-Jet Selection for the ATLAS High-Level Trigger

The ATLAS detector will operate in a highly challenging environment that requires a sophisticated trigger strategy. The online b-jet selection is an important part of the trigger which greatly improves its flexibility and extends the ATLAS physics programme. More specifically, b -jet acceptance is increased and background reduced by lowering jet transverse energy thresholds at the first trigger level and then applying b-tagging at subsequent levels. Several physics channels, especially those with topologies containing more than one b -jet, benefit from requesting this kind of trigger firing. We present an overview of the b -jet trigger algorithms and menu at the experiment start-up.