1. Update on H/Abb -> 4b’s process (4jet Trigger) Kohei Yorita Young-Kee Kim University of Chicago @ the FTK Meeting on Sep. 7 th, 2006

2. 2 Review (What’s been done so far) TDR-style-analysis, i.e. Based on Atlfast jet and Used single threshold. This improvement is given by lowering 4J threshold from ~60-70 GeV to 40 GeV where LVL1 output rate is 1KHz. (TDR (~200Hz) @ ~60 GeV) But LVL2 out can be ~100Hz by FTK btagging.

3. 3 Multi-Threshold Scan (Atlfast basis) Cut valueTrig RateS(500)Cut valueTrig RateS(500) Default (w/o FTK)70 70 90 Hz6.3 %70 70 90 Hz6.3 % Default (w/FTK)40 40 830 Hz24.2 %40 40 830 Hz24.2 % 4 th Jet Pt > 20 GeV4 th Jet Pt > 30 GeV Case1: j1>j2>j3>j480 70 50 20999 Hz37.3 %90 60 40 30957 Hz33.3 % Case2: j1>j2>j3=j4100 90 20 20954 Hz45.1 %100 50 30 301001 Hz34.6 % Case3: j1>j2=j3>j4100 50 50 20960 Hz37.3 %60 50 50 301015 Hz30.5 % Case4: j1=j2>j3>j480 80 40 201009 Hz41.3 %70 70 40 30938 Hz33.0 % Case5: j1>j2=j3=j4130 20 20 20916 Hz45.9 %100 30 30 301056 Hz34.7 % Case6: j1=j2=j3>j460 60 60 20795 Hz31.5 %50 50 50 301027 Hz30.6 % Case7: j1=j2>j3=j490 90 20 20989 Hz45.3 %70 70 30 301044 Hz34.5 % Case8: j1=j2=j3=j420 20 10.7 KHz54.3 %30 30 2.6 KHz36.5 % Each point was selected when trigger rate became closest to 1KHz in each case. Keeping 1KHz by increasing 1 st (~80 GeV), 2 nd (60-70 GeV), and 3 rd (40-50) jet Pt but by lowering 4 th jet Pt (20, 30 GeV), Signal (M_A = 500 GeV) acceptance increases by a factor of 1.5~2 !!!

4. 4 Trigger Rate Calculations with New Samples and LVL1 Parameterization Note : Lum = “2”x10 33 Trigger RateLVL1:4J(40) 2->2+3+4 y>10 83.9 Hz 2->2+3+4 y>25 137.8 Hz 2->2+3 y>10 150.5 Hz 2->2+3 y>25 165.5 Hz Looks very close to Erik’s Numbers (Note luminosity) Given the assumption that LVL1 output max is 1KHz, we can lower the threshold to ~20GeV(8x8 calo.) from 40 GeV(8x8 calo.).

5. 5 Some issues : Old vs New Sherpa Samples Note : Lum = “2”x10 33 All new sherpa samples give lower rate than old 2->2+3, yt>25 sample Which was used as a default so far. Old : 1KHz @ 40 GeV New : 1KHz @ 30 GeV. If this is “expected” feature and Not due to bugs, We will have to redo sensitivity study By lowering 4 th jet pt to 30 GeV, not 40 GeV

6. 6 > Things to do : (To Finalize) - Multi-Threshold Study by using “LVL1 Parameterization”. - In progress now. - Good to try to measure dijet (H/A) mass. - Systematics ? - Final Check with other generator & setting. - Documentation … -- Being Prepared ! - Any other issues ?