The SVT Bypass for a Forward Lepton wide coverage in the CDF Trigger

The silicon-vertex-trigger (SVT) [1,2] at CDF is made of two pipelined processors: the associative-memory, AM [3,4], finding low precision tracks (roads) and the track-fitter, TF, refining the track quality with high-precision fits. We propose to extend the SVT use, now mostly focused on B-physics, to high-PT physics as a tracker in the forward/backward region. The upgraded SVT structure is easily improved working on firmware, or connecting the existing general purpose FPGA-based SVT boards, named Pulsars, with other Pulsars in a lego-structure. In particular, SVT can easily extend the prompt-lepton acceptance providing silicon-only tracks where the drift-chamber coverage is poor or missing (pseudorapidity larger than 1). Since prompt-leptons from high-PT events do not require precise impact parameter measurement, we don't need to measure these tracks with the maximum silicon detector resolution. We enlarge the use of the AM, to detect tracks above a defined PT threshold. We propose a bypass that brings the new thin roads found by AM, directly to the level-2 CPUs. While the slower full-resolution path (TF) will have to digest the normal AM road production, four new Pulsars will deliver new roads from AM to L2-CPU. All the hardware exists, needs only to be assembled. We present the bypass architecture, the forward-track quality and their possible use in Higgs triggers. The system timing is estimated from simulation on real data and measurements on test stand.