Single Top Trigger Studies Top Trigger Meeting, 9 May 2007 - 1Patrick Ryan, MSU

Single Top Trigger Studies

Top Trigger Meeting

9 May 2007

Patrick Ryan

Single Top Trigger Studies Top Trigger Meeting, 9 May 2007 - 2Patrick Ryan, MSU

Level 1 Muon Trigger

• Level 1 Muon Triggers Exclusive in Version 12• Only one trigger fires for each muon

• MU06 only accepts events between 6 and 8 GeV• MU08 only accepts events between 8 and 10 GeV

• Muon triggers will be inclusive in Version 13

• Muon Trigger Flags• Each trigger has single Integer flag for each event• 2 muon candidates can fire 2 separate muon triggers

• An event can have both MU06 and MU08 fired• Muon trigger can fire even if event has 0 truth muons

• Muons not coming from W with pT < 5 GeV (not stored in Truth tree)• Muons not originating at vertex• Punch-throughs• Want to investigate these events to make sure we understand them

• See following slides

Single Top Trigger Studies Top Trigger Meeting, 9 May 2007 - 3Patrick Ryan, MSU

Truth Information in TopView

• Truth0 Tree• All muons from W decay

• Other muons (from jets & punchthu only if pT > 5 GeV)

• TruthAll Tree• All muons regardless of pT

• Need all muons to compare to muon trigger efficiency• Large and slow

Single Top Trigger Studies Top Trigger Meeting, 9 May 2007 - 4Patrick Ryan, MSU

Muons Triggers

• Ran over 56250 total events (5200 Sample)• Lower threshold triggers accept more events with 0 muons

• Muons with pT < 5 GeV can fire triggers (fake rate)• Becomes less likely for higher trigger pT thresholds

Trigger Passed 0 Truth Muons 0 TruthAll Muons

MU06 1723 407 (23.6%) 162 (9.4%)

MU08 1293 164 (12.7%) 87 (6.7%)

MU10 3338 363 (10.9%)

MU11 3623 109 (3.0%)

MU20 3911 52 (1.3%)

MU40 17017 59 (0.3%)

Single Top Trigger Studies Top Trigger Meeting, 9 May 2007 - 5Patrick Ryan, MSU

MU06 and 0 Truth Muons

• Plot TruthAll muons• 1723 of 56250 total events total events passed MU06• 407 of 1723 events had 0 Truth Muons (left plot)• All TruthAll muons in events with 0 Truth muons have pT < 5 GeV

• Confirms that these muons come from somewhere other than vertex

407 events having 0 Truth Muons

All muons in all events with 0 Truth Muons

Single Top Trigger Studies Top Trigger Meeting, 9 May 2007 - 6Patrick Ryan, MSU

MU06 and 0 TruthAll Muons

• 162 of 407 events with 0 Truth also had 0 TruthAll muons• Multiplicity distributions of trigger sample shifted slightly to right

Single Top Trigger Studies Top Trigger Meeting, 9 May 2007 - 7Patrick Ryan, MSU

MU06 and 0 TruthAll Muons

• Higher statistics sample for pT and eta distributions• Trigger sample slightly lower at low pT and higer at high pT

• Trigger sample slightly higher around eta = 0.

Single Top Trigger Studies Top Trigger Meeting, 9 May 2007 - 8Patrick Ryan, MSU

MU06 and 0 TruthAll Muons

• Where do events with 0 TruthAll Muons come from?• Muon LV1 triggers only on muons originating at vertex• Possibilities of non-vertex muons include

• Muons from jets• Muons from punch-throughs

• Check LV1 Muon trigger rates for muons from jets and punch-throughs• Alessandro DiMattia working on this

Single Top Trigger Studies Top Trigger Meeting, 9 May 2007 - 9Patrick Ryan, MSU

Single Top Muon Efficiencies

• TopView Version 1212 MuidTauRec 003 ntuples• Truth efficiencies

• No selection cuts• Ratio of number of events before and after trigger

• Reconstructed efficiencies• Apply common single top event selection

• At least 1 high-pT lepton (e or )• Electron pT > 25 GeV• Muon pT > 20 GeV

• No secondary lepton with both pT > 10 GeV and -1.475 < < 1.475• Njet ≥ 2

• pT1 > 30 GeV

• pT2 > 25 GeV

• NJetB-tagged ≥ 1 where b-tagged jet has pT > 35 GeV

• ETMiss > 25 GeV

• Ratio before and after trigger calculated after event selection

Single Top Trigger Studies Top Trigger Meeting, 9 May 2007 - 10Patrick Ryan, MSU

Muon Efficiencies 5200 (ttbar) Sample

• Compare to ttbar group study (Attila’s latest T5 talk page 4)• Calculated efficiencies using 2 methods

• Wrong: (MU06 + MU08 + … + MU40) / Total• Overcounts since a single event can have two muons triggers fired

• Right: (MU06 || MU08 || … || MU40) / Total (shown above)

Single Top Trigger Studies Top Trigger Meeting, 9 May 2007 - 11Patrick Ryan, MSU

Muon Efficiencies 5500 (Wt) Sample

• Truth and reconstructed efficiencies have same shape• Reconstructed efficiency about 15% higher than truth efficiency

• We expected reconstructed efficiency to be even higher (around 90%)

• About 8% efficiency change between MU06 and MU40• Highest efficiency of the single top channels

Single Top Trigger Studies Top Trigger Meeting, 9 May 2007 - 12Patrick Ryan, MSU

Muon Efficiencies 5501 (s-channel) Sample

• Truth and reconstructed efficiencies have same shape• Reconstructed efficiency about 25% higher than truth efficiency

• We expected reconstructed efficiency to be even higher (around 90%)

• About 10% efficiency change between MU06 and MU40• Lowest effiency of the single top channels

Single Top Trigger Studies Top Trigger Meeting, 9 May 2007 - 13Patrick Ryan, MSU

Muon Efficiencies 5202 (t-channel) Sample

• Truth and reconstructed efficiencies have same shape• Reconstructed efficiency about 20% higher than truth efficiency

• We expected reconstructed efficiency to be even higher (around 90%)

• About 10% efficiency change between MU06 and MU40

Single Top Trigger Studies Top Trigger Meeting, 9 May 2007 - 14Patrick Ryan, MSU

Plans

• Finish LV1 Muon study

• Efficiencies for e, jets, etc.

• Efficiencies at Level 2 and Event Filter