E/gamma Triggers

Sam Harper

RAL

E/gamma Meeting

06/09/10

2/8

Introduction • E/gamma trigger menu is evolving rapidly

– we are in an exceptional time of the experiment where the LHC luminosity is rapidly increasing

– we are not fully commissioned

• we have two new menus left this year– 2E31, deploying imminently – 6E31, first proposal earlier today in TSG

• note: in 2E31: all triggers have H/E<0.15 applied– names do not change (this is still being debated…)– Photon filternames go from PhotonEtXCleanedHcalIsolFilter

to PhotonEtXCleanedHEFilter – this is not a new thing, it was originally planed to have H/E

on all EG triggers at L1 but this year it has instead moved to HLT

3/8

EGEle at 2E31

• current ele triggers at CMS, we have:– standard (H/E<0.15 + PM– CaloEleID (sigmaIEtaIEta < 0.014 <0.03)– EleId (dEtaIn,dPhiIn,sigmaIEtaIEta– EleIdIsol (dEtaIn, dPhiIn, sigmaIEtaIEta, isolEm, isolHad,

isolTrk)

4/8

Method

Data:• bkg: Photon10 skim• signal: a skim of W (MET>30GeV) /Z (two eles)

passing WP95 in 361p4 prompt reco

MC:• 381 W->enu RelVal• RECO+ HLT:

– CMSSW_3_8_1:• RECO GT MC: MC3XY_V9, data: GR10_P_Vl• HLT GT MC: MC3XY_V9, data: GR10_H_V8

5/8

CaloID Variables: All SC

X/Y:

X = nr events with RECO value < cut where HLT cut fails

Y = nr events with RECO value < cut

84/56931

(0.0015)

43/36526

(0.0012)

21/47644

(0.0004)

50/25570

(0.0020)

Differences all at per mill level

note: events are required to be “good” η region

6/8

Calo Isol Variables: All SC

X/Y:

X = nr events with RECO value < cut where HLT cut fails

Y = nr events with RECO value < cut

note: events are required to be “good” η region

123/24983

(0.005)

184/23501

(0.008)

328/53727

(0.006)

958/24113

(0.04)

7/8

Track matching Variables: Zs

• note, the matching is pretty bad for all jets

• better for Zs• also note: I

don’t think I have the alignment properly set in endcap

note: events are required to be “good” η region

8/8

Tracker Isolation: Zs

• tracker isolation is not well reproduced in the HLT – I’ve tried to make version which is always smaller although

this is challenging

9/8

Trigger Performance: 2E31 Menu

• Z dependence in startup windows eff:– been investigating, some EB events are actually failing

dphi cuts… – also includes H/E cut

10/8

PM + H/E Efficiency: Ws

11/8

Ele12 EleIdIsol Eff after PM+H/E

• efficiency after L1+ET cut + PM

• I havnt managed to get the new endcap alignments so removed dEtaIn in endcap– this will run as a backup trigger…

12/8

LEleId Efficiency after PM + H/E

• AKA our online tracking efficiency…• better than MC in barrel, endcap worse

– wondering if the endcap missalignment is contributing

13/8

CaloEleId After PM + H/E

• now theres a trigger efficiency I like

14/8

EleId Efficiency

• still have alignment issue in endcap so no point showing it

15/8

Plans for the Future

• GsfTracking in the HLT: A. Holzner• double object triggers

– cross – channel triggers, ie with mu’s, MET etc– single seeded di-pho/ele triggers

• only require 1 obj to pass L1• worked on by R. Covarelli building on work by B. Dahmes

– PAG input vital

• triggering will be even more challenging next year– I encourage every analysis to be thinking about how they

trigger their signal and ensuring its in the menu• single electron triggers with Et<30-40 GeV will require heavy id

Finally EG HLT is undermaned: Please get involved (even if its just making trigger efficiencies for your analysis

16/8

Backup

17/8

Trigger Selection Variables• we have 4 ID variables

– dEtaIn, dPhiIn, sigmaIEtaIEta, H/E

• we have 4 Isolation variables– EM Isolation, HCAL isolation, Trk Pt isolation (Ele), Trk Pt

isolation (Pho)

• I have tried to make these variables either identical or value which is always looser than RECO– this is not always possible– I have very few ways of altering dPhiIn, dEtaIn, they are

what they are

• I consider H/E, sigmaIEtaIEta to be very good, Calo Isolation to somewhat good and dPhiIn, dEtaIn, tracker isolation to be not so good-critiera is solely RECO-HLT agreement

18/8

EGPho at 2E31

• note all E/gamma triggers have H/E<0.15 – 1 exception is a high threshold Photon trigger for safety

• most notable change for exotica is that our uncleaned high PT trigger is gone– it was going to be 500GeV at 6Hz , rate and threshold was

too high to justify and wouldn’t have survived next menu

19/8

6E31

20/8

Photon35

• various options for this trigger:– sigmaIEtaIEta– tighten track isolation variable

• cone size to 0.03, min pt to 1.0 GeV• decreasing veto cone size 0.03

– tighting cuts – going to 0.4 cones

• note I noticed when checking, ele/pho isol is different– pho has 2.5 crystals width, 3.5 cone

21/8

Pho35 Eff

• good efficiency

22/8

Revised Menu

• the dEtaIn safety trigger adds 0.5Hz to a 34.8 Hz• overlap with EGPho is 7.8Hz (22% of EGEle) • I would also like to run a HLT_Ele17_SW_EleId_L1R

trigger– this adds no rate but if people want a single electron trigger

at 17 GeV at 6E31, this is a candidate…

• both triggers are in confdb

23/8

Validation of Paths

• for 25 GeV Z->ee WP95 electrons which pass L1 and are fiduical in EB or EE (total 746)

• EleId paths are affected by dEtaIn missalignment– in theory should be fixed but I have got the right settings?

Trigger N pass Eff

Ele10 738 98.9 ± 0.3

Ele12_EleIdIsol 687 92 ± 1

Ele12_EleIdIsol_NoDEtaInEE 717 96 ± 1

Ele12_EleId 689 92 ± 1

Ele17 738 98.9 ± 0.3

Ele17_CaloEleId 738 98.9 ± 0.3

Ele17_EleId 689 92 ± 1

Ele17_LEleId 722 97 ± 1

Ele22_CaloEleId 738 98.9 ± 0.3

Photon20 744 99.7 ± 0.2

24/8

Proposal: ET thresholds

• physics wants a 15 GeV trigger for 20 GeV electrons– HLT turn on better then this, we propose 17 GeV for 20GeV

– plateau is at 18 GeV• curve driven by difference in ET w.r.t (0,0,0) and w.r.t primary vertex

• at this stage HLT does not distinguish between ele + phos

25/8

Rate reduction

• 2 GeV = ~30% rate reduction: very compelling