Current Studies

We are currently investigating the best strategy at Level 3 to collect a reasonably small-sized, pure sample of multijet events with heavy flavors.
If, as our previous studies predict (and cdf-5547), the input rate to Level 3 can be kept below 2-3 Hz by the simultaneous calorimetric and 2-SVT track requirements, we have the time to perform a full tracking reconstruction (in the best of cases), saving to disk events that possess at least one SECVTX tag; in the worst case, we will anyways be able to confirm the presence of two good displaced tracks by doing a regional tracking around the SVT track candidates.
It has been argued that the proposed trigger would largely overlap with the inclusive b-jet trigger proposed by Xin Wu. Although this is certainly true, the two triggers are aimed at completely different physics searches. We do not feel comfortable to tie the destiny of the Higgs multijet analysis to others, especially when the dataset we would need to analyze would be huge, the trigger collecting the data being on the constant threat of getting prescaled if high luminosities are attained, and when there is a very sound, viable, and simple alternative.
It is to be noted that the looser requirement of one displaced SVT track at Level 2 will probably jeopardize the possibility of doing something smart at Level 3. Currently, the cross section of multijet + 1 SVT (d>100 um) requirements can be estimated at sigma=21 +- 1 nb, implying an input rate to L3 of 2.1 Hz (at 10³² cm^-2 s^-1).

Work on this topic is still ongoing, more precise results will be posted here soon.

Giorgio_Cortiana

Last modified: Tue Oct 30 09:06:59 CST 2001