Andrew Brandt, U. Texas at Arlington

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Andrew Brandt, U. Texas at Arlington

Trigger Workshop October 31, 2003Fermilab

QCD Triggers in V13+Beyond

QCD Trigger EffortQCD triggers have been very stable:1) Significant early effort by John Krane and Greg Davis2) Triggers work well, have excellent rejection3) Not too many tools for jets (PT and?)

4) Very little manpower

Recent effort has been limited to Pavel Demine looking at trigger efficiencies of each trigger version, no trigger development (NEW RESULTS)

Now have Notre Dame student Hong Luo (with Don Lincoln) studying jet triggers, working on improving triggers (NEW RESULTS)

Big effort underway to develop FPD trigger capability1) Carlos Avila and Daniel Mendoza developed special run trigger capability2) Manchester group working on FPD_LM system: Brian Cox (Prof), James

Monk (GS), Scott Kolya (Eng), Dave Mercer (Eng) 3) DFE +Trigger Manager: Mario Vaz, Daniel Mendoza, Renata Rodriguez

(UERJ GS), AB

Comments on QCD Physics

QCD does *NOT* equal prescale!

Inclusive jet and dijet mass are discovery channels:Highest PT and highest mass events should not be prescaled.

Highest PT diffractive and double pomeron events should also not be prescaled.

Looking for rare exclusive double pomeron events in dijetchannel and C to J/, requires maximum statistics.

Prescaled Jet Triggers

JT_8TT CJT(1,5) L3(1,8) e80-l30-m10 JT_15TT CJT(2,3) L3(1,15) e80-n30-m20 JT_25TT_NG CJT(2,5) L3(1,25) e80-l60-n30-m20JT_45TT CJT(2,5) L3(1,45) e80-l60-n30-m20JT_65TT CJT(3,5) L2(1,20) L3(1,65) l80-n60-m303CJT5 CJT(3,5) q4CJT5 CJT(4,5) q

q=0.1 Hz e=0.1 l=0.25 n=0.5 m=1.0

These triggers are used for inclusive jet cross section,dijet mass, and diffractive jet physics; we need to establishthat we will have sufficient statistics with a higher lum profile.

JT_95TT+JT_125TTBoth currently unprescaled at all lums, if rate on JT_95TT becomes a problem, can go to JT_125TT at highest lums.

JT_95TT:CJT(4,5) L2JET(1,30) L3JET(1,95)40E30: L1=52 Hz L2= 39 Hz L3=0.52(unique fraction 0.27 for 179614 40E30 prescale set, likely uniquefraction will decrease with luminosity, so prescaling will give marginal savings)

JT_125TT:CJT(4,7) L3JET(1,125)40E30 L1=11Hz L2= 11 Hz L3=0.12Expect scaling with luminosity ->0.24 Hz at 80E30

If V13 were today we could change JT_125TT to same L1, L2 as JT_95TT. Should consider 95 ->105 (L3 rate went up by x2 from non-linear corrections) Raise L2 Threshold? Use CJT(3,5)?

• WARNING! Really new results (courtesy of Hong+Don) <24 hours old, QCD group won’t see until Monday• GOALS: Investigate L2 thresholds, develop tools to enable trigger

development, especially for high dijet invariant mass trigger (L2 +L3 , mass cuts)• Hong incorporated TrigSim into Ariel’s d0root package• Needs p15.06.00 to get RECO & TrigSim into TMBTrees• Available information

– L1CalEMTwr, L1CalTwr, L2EM, L2Jet, L2Muon, L3ToolResults• Analyzed two trigger list versions

– Data from Pavel’s DST files [RECO r13.06.01]– v9.31 80,000 events– v11.02/03 54,000 events

• RECO Jets not JES corrected (Don thinks)• Standard jet quality cuts • R(L2 Jet, RECO Jet) < 0.75

New TrigSim Results

JT_65 L2 Pt Before+After Cuts

V11 much worse than V9 but possibly no bad run cuts

Looks like 20 GeVis a bit conservative

JT_95 L2 Pt Before+After Cuts

Looks like 30 GeVis a bit conservative

Compare V9+V11

Some gains by raising L2 threshold, need to be quantified+V12

Comparison of L2 and RECO

L2 vs RECO After Cuts

• Previously used ratio of jet triggers—only gives relative efficiency,

problematic at low end

• Pavel Demine’s new method uses muon triggers with no calorimeter requirements, use as cross check on 100% efficiency thresholds

• Efficiency for jet trigger= muon*jet trigger/muon vs PT

• Moriond data with p13.05.00 and p13.06.01

• Standard jet quality cuts

New Efficiency Method

Inefficiency in V8 believed to be real, data not being used

Gap+Jet TriggersJT_15TT_GAPN or S CJT(2,3)+GAP L3(1,15) Prescaled, currently .3-.4 Hz each L<40E30; <.1Hz at 40 E30 e80-l40-n30?

JT_15TT_GAPSN CJT(2,3)+GAPS L3(1,15)Currently unprescaled 0.6 Hz at 40E30 expect a prescaleat higher luminosity unless can improve trigger (or naturalprescale from double gap takes hold)

JT_45TT_GAPN or S CJT(2,5)+GAP L3(1,45) Currently prescaled by 2 at 40E30 .08 Hz each would like to keep unprescaled at least to 60E30 (like highestinclusive ET trigger). Also will have natural SI prescale (note s80-u60 in prescale file!)

JT_45TT_GAPSN CJT(2,5)+GAPS L3(1,45)Unprescaled at all luminosity 0.03 at 40E30 *Also have 3 zero-bias+gap triggers

These triggers are used for single diffractive and doublepomeron jet physics (Gaps and FPD)

J/ +Gaps

J/ +Gap2MT1_2TRK_GAPN = 2MT1_C_2L2L_2TRK + ALMNorth[v]2MT1_2TRK_GAPS = 2MT1_C_2L2L_2TRK + ALMSouth[v]

Currently prescale of 4 at 30E30, 200 at 40E30, Unprescaled rate: .25 Hz @20E30 .5 Hz@40E30 e80-l60-n40 would be goodCould be unprescaled at all lum, when low PT track match works

J/ +Gaps2MT1_2TRK_GAPSN = 2MT1_C_2L2L_2TRK + ALMSouth[v]ALMNorth[v}<.01 Hz at 20E30 <.04 at 80E30 should be unprescaled at all luminosity

These triggers are being used to search for exclusive J/ and C , a key steptowards validating diffractive Higgs models

FPD TriggersExpect to have all 18 FPD detectors, and trigger scintillators in readout at end of shutdown.(!)

•Currently can only trigger using special runs (NIM to generate AND/OR terms).

•Need LM vertex board (<6 months, according to Brendan) combined with Trigger Manager (commissioning starting in next few weeks) for scintillator based triggers.

•Could have DFE-based triggers through TM earlier

•Will need some resources, bandwidth, exposure groups, trigger bits

Proposed strategery: add high rate monitor and calibration triggers (elastic, inclusive diffractive) in separate global run not to be recoed.Use TM to define a gap exposure group (currently have 3) and an FPD exposure group. A few global run triggers for double pomeron, J/, and dijets. Other diffractive physics symbiotically.

Workshop GoalsQCD bandwidth is already very limited, few Hz at low lum, <2 Hzat intermediate lums (40E30). We were already gutted by meisters due to V12 list failures. (Rate to tape is only issue, since the QCD triggers have excellent rejection). 20% of nothing is nothing, can’tsave the experiment by cutting QCD.

We will have new physics capability after shutdown. Modest expansion in bandwidth needed—some of it off the farm books.

Tools in development or under investigation:L1 FPD, L2 and L3 +mass cuts, L2 Gap Tool, L3 SI toolL3 Vertex, Timescale couple/few months (longer than mid-Nov)Large tiles?

QCD Conclusions•More activity in QCD triggers than ever before

•New promising studies on L2 and efficiencies

•Will have new L2 thresholds for V13

•Working on FPD triggers and new tools

•Need follow-up on exposure group discussion

•Everyone else should cut hard so we can get a few bandwidth scraps!

Andrew Brandt, U. Texas at Arlington

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