Online b-jets tagging at CDF

We propose a method to identify b-quark jets at trigger level which exploits recently increased CDF trigger system capabilities. b-quark jets identification is of central interest for the CDF high-P_T physics program, and the possibility to select online b-jets enriched samples can extend the physics reaches especially for light Higgs boson searches where the Hrarrbb macr decay mode is dominant. Exploiting new trigger primitives provided by two recent trigger upgrades, the Level2 XFT stereo tracking and the improved Level2 cluster-finder, in conjunction with the existing Silicon Vertex Tracker (SVT), we design an online trigger algorithm aimed at selecting good purity b-jets samples useful for many physics measurements, the most important being inclusive Hrarr bb macr searches. We discuss the performances of the proposed b-tagging algorithm which must guarantee reasonable trigger rates at luminosity greater than 2times10³² cm^-2 s^-1 and provide high efficiency on Hrarrbb macr events.