INFN-Padova's Multijet + Heavy Flavor Trigger Page

P.Azzi, G.Busetto, A.Castro, G.Cortiana, T.Dorigo, M.Giordani, L.Scodellaro, R.Valandro

The italian answer to Humprey

Generalities



A multijet trigger with relatively low thresholds on jet ET, enriched with heavy flavor decays by the request of a soft lepton tag or displaced tracks, will enable an independent search for Higgs boson associated production and decay into b-quark pairs.
Multijet events may also be the search field for several supersymmetric signatures, and they substantially help collecting ttbar decays; a single top signal may also be sought with a few fb-1.

The proposed triggers are:

red Multijet + soft lepton tag: such a trigger relies at Level 1 on the single tower trigger with ET above 10 GeV, whose accept rate has been recently verified to be 2.5 kHz. At Level 2, three calorimeter clusters exceeding 10 GeV are requested, plus a sum of transverse energy of all clusters above 90 GeV; the accept rate has been shown to be close to the predicted value, 15 Hz. At Level 3, a search for electron and muon tags of the jets can be performed, lowering the rate by an order of magnitude.

red Multijets + SVT: the same calorimetric requirements of the former trigger, plus the request of two SVT tracks with impact parameter larger than 100 microns at Level 2, is estimated to yield an input rate to Level 3 of about 1.5 Hz. At Level 3 it should thus be possible to operate a full tracking reconstruction, to obtain a small high-purity sample of heavy flavor decays. The matter was discussed in a talk at the TDWG meeting on September 6th.

red A trigger strongly related to the two highlighted above is the well-established top-multijet trigger, which is of course needed for the replica of the all-hadronic ttbar search performed in Run I. Our studies show that by requiring a total Sum ET larger than 120 GeV at Level 1, a cluster Sum ET above 125 GeV plus four clusters with ET above 15 GeV at Level 2, and a jet Sum ET above 125 GeV plus four 0.4-cone jets with ET above 10 GeV at Level 3, we will get an effective cross section of 5.2 nb. The total efficiency of the signal should be larger than 60%.



Status of ongoing work



red Validation of calorimetric data and rates (updated October 19th, 2001)
red SVT output studies, d-phi correction (updated September 11th, 2001)
red Application of SVT simulation to Run II data (updated September 11rd, 2001)
red Current Studies (updated October 30th, 2001)
red Ongoing work with the Soft lepton trigger at L3 (not yet available)
red Miscellanea (available soon)


Recent Talks:


red talk at the TDWG on Sept 6th 2001
Multijet trigger: studies and validation of recent data. Talk at the TDWG meeting at FNAL, Sept 6th 2001.
red talk at the Collaboration Meeting on Sept 21st 2001
Multijet+SVT trigger. Talk at the Collaboration meeting at FNAL, Sept 21st 2001.
red talk at the Congresso Nazionale SIF 2001 (Italian Society of Physics) on Sept 27th 2001
Higgs search in the multijet final states at CDF. Talk at the Congresso Nazionale SIF (Italian Society of Physics)in Milan Sept 27th 2001.
red talk at the Exotic Trigger meeting, Nov 21st 2001
Higgs Multijet+SVT trigger.A short report red Talks Topics (updated November 24th, 2001th, 2001)


Documentation



red CDF-5485: A RunII Soft Lepton Tag-based Trigger for H0+V:
A comprehensive description of the design of the multijet+SLT trigger for the Higgs search.

red CDF-5534: A Study of SVT Performance on Multijet Events
for the Higgs Search: Background Rejection and Timing Issues (part I):
The description of several studies performed with Run II WH/ZH simulations and Giovanni Punzi's SVT simulation, to ascertain the possibility to analyze the complicated multijet events in time for a L2 decision and with a fruitful noise rejection, given noise in the silicon and other effects.

red CDF-5534: A Study of SVT Performance on Multijet Events
for the Higgs Search: Background Rejection and Timing Issues (part II):
An improved version of the former note.

red CDF-5547: RUN-II Higgs Multijet Trigger with the SVT:
Toni Munar's work on the subject. It includes a study of the expected rates of a SVT trigger with multijet requirements which is based on Run I data.



Source code





Useful links



red The Triggers and Datasets working group site
red The SVT home page in Pisa
red The SVT page of Stefano Belforte
red The CDF II home page in Padova
red T.Dorigo's home page
red P.Azzi's home page
red L.Scodellaro's home page
red G.Cortiana's home page
red R.Valandro's home page


Giorgio_Cortiana
Last modified: Sat Nov 24 09:24:25 CST 2001