# Presentation: 016830

## SUSY Search - mSUGRA scenario

- Search for Chargino and Neutralino into 3 leptons and MET
- mSUGRA R-parity conserved scenario

-  Overview and results for Summer Conferences 2005
-  Improvement to the acceptance towards Winter Conferences 2006
-  Validation of 6.1 data
-  Conversion study
-  Plan

- 8/01/04

## Search overview

- Chargino and Neutralino are a mixed state of the SUSY partner of gauge and Higgs boson
- Two production modes
-  t channel (suppressed)
-  s channel (dominant)

- 8/01/04

## Analysis approach

**First lepton is high pt**  DATASET, high pt single muon bhmu0d (CMUP18 && CMX18)
**Large Missing Transverse Energy**  discriminating variable in Rp searches

**3 isolated and separated leptons + large MET**

**Lepton pt range** driven by the mass difference between chargino and neutralino
**Large missing transverse** energy due to the escaping neutrino and massive neutralino (LSP)

**Blind analysis**** performed as a ****COUNTING experiment**** **
**PURDUE exploring the ********+********/e channel (to be combined to other channels for publication)**
-  A priori optimization of the event selection
-  Blind to data in signal region
-  SM prediction tested in 15 control regions (invert kinematic cuts)
-  “Open the box”

- 8/01/04

## Event selection and results

- Major background:
-  **Drell Yan** and **Diboson**
- (estimated from MC)
**Fake leptons**
- (estimated from data)

| Selection | Diboson | t-tbar | DY +  | DY + Fake  | TOT | Susy | S/√B |
| --- | --- | --- | --- | --- | --- | --- | --- |
| trilepton | 0.50 | 0.003 | 1.7 | 0.66 | 2.85 | 0.48 | 0.3 |
| Mass | 0.07 | 0.003 | 0.8 | 0.20 | 1.06 | 0.42 | 0.4 |
| Jet | 0.07 | < 0.004 | 0.8 | 0.19 | 1.04 | 0.42 | 0.4 |
| MET | 0.04 | < 0.004 | 0.035 | 0.01 | 0.09 | 0.37 | 1.2 |

- Blessed Analysis

**What are the major backgrounds **
**with signature = 3 isolated leptons and large MET ?**

- 8/01/04

## Improvement to the blessed analysis

-  Re-investigated dimuon regions with full statistics, tuned EWK Z and Z MC samples exploited
-  Extended to more channels:
-  CMIO included as a second muon
-  e channel (see Else’s talk at SUSY Meeting Oct 18th)
-  Good agreement in all 15 control regions
-  Acceptance improved (by adding the CMIO channel only) by a factor ~2 with respect to the blessed analysis

| nev | DiBoson | DY | Fake | Tot | Susy | S/√B |
| --- | --- | --- | --- | --- | --- | --- |
| Signal Region | 0.01
0.01 | 0.097
0.04 | 0.12
0.06 | 0.32
0.04 | 0.7
0.03 | 1.2 |

- 8/01/04

## Combined limit (prelim)

- Acceptance: up from 0.75% to 1.42%

****** ****channel only**

**Blessed result:**
- 0.37 SUSY events, limit on BR: 1.2 pb
**Now**: 0.70 SUSY events
-        0 obs  limit of 0.62 pb
-       1 obs  limit of 0.97 pb

**Blessed Analyses**
**(e******** included)**

**Blessed Analyses**
**(e******** and CMIO** **included)**

**346 pb****-1**

**800 pb****-1**

- 8/01/04

## Slide 7

- 8/01/04

## Validating 6.1

- Validating the first 200pb-1 of 6.1 data available
- run range [190697;203799] from August 2004 to September 2005

-  compare 5.3 data to 6.1 data
-  compare 6.1 data to 6.1 MC (*on going* – 6.1 ntuplizer issues)

- _What is different with respect to 5.3 ?_
- Compiler switch from KAI to GCC
- Tracking specific improvements
- Include t0 into the track parameters fit
- Lost segments recovery
- Avalaibility of CMX keystone and miniskirt
- _How do gen5 and gen6 data compare ?_
- Muons and tracks – see next slides
- Electron
- CEM E scale lower in 6.1 (0.2 GeV)
- PES 5/9 ratio peaks at higher values in 6.1
- CES dx and dz narrower in 6.1
- Need nvtx correction to the ID
- Jets
- 1% higher scale in gen6 east plug

- For tracks with Pt>300 MeV
- Determine t0 per primary vertex
- Constraint the tracks to the vertex t0
- Improve chi2/dof, residuals

- Search for hits in missed SLs
- Refit the tracks one extra time
- Reduces the fraction of lost segments in the inner superlayers by 90%
- Makes the tracking efficiency more uniform vs luminosity
- Increases the number of hits/track

- 8/01/04

## More COT hits both axial and stereo – more layers
Chi2 peaks at lower values 
Improves due to the event based use of t0
Tighter cuts might improve fakes rejection

- Chi2 peaks at lower values
- Improves due to the event based use of t0
- Tighter cuts might improve fakes rejection

- COT Chi2 and hit distributions

- Shown at JPM

- 8/01/04

## z0 distribution Gen5 vs Gen 6 

- Post-shutdown – 6.1 data

- RMS:  0.202+/-0.004 cm

- RMS:  0.136+/-0.002 cm

- Mainly due to segments recovery in the inner SL

- Shown at
- Coll Meeting

- Pre-shutdown – 5.3 data

- 8/01/04

## Momentum Scale

- Pre-shutdown

- Post-shutdown

- Mean: 90.84 GeV/c2
- RMS:  2.516+/-0.036 GeV/c2

- Mean: 90.80 GeV/c2
- RMS:  2.497+/-0.046 GeV/c2

- Shown at
- Coll Meeting

- 8/01/04

## CMX Geometry

- MINISKIRT

- MINISKIRT

- KEYSTONE

- 8/01/04

## Phi and Eta distributions  

- Phi and Eta distributions

- TIGHT

- CMIO

- 8/01/04

## Run dependence

- Current issue: understanding the run dependence of yield and cross section
- Clear run dependence in W yield and cross section – less pronounced in Z events
- Similar pattern in electron and muon channels – luminosity issue?
- Observed run dependence in old data –confirmed (worse) in new data
- Joint physics task force – effort documented at JointPhysics/Event Yield Studies

- Trigger requirement only

- Tight muon selection

- 8/01/04

## Slide 15

- 8/01/04

## Conversion study

-  The current algorithm (standard) is based on selecting track pairs as conversion candidate
-  Need to evaluate the residual conversion (no partner track is found)
-  Largest reducible background
-  Need to improve the rejection power
-  Investigating the contribution in details
-  Compare data and MC in control regions when we allow conversion
-  ISR not included in the current DY sample
-  Need to estimate the contribution
-  Compare to the estimate from MC (ISR+FSR) – generated with tight kinematic cuts

- 8/01/04

## Tagging efficiency

- The relative residual conversion can be estimated from the conversion efficiency

- MC sample: Baur MC Z with Z (ISR +  FSR)
- Data sample: bhmu0d (looked at edil0d SUSY_DILEPTON)
- Select Z event to reduce fake contributions with large invariant mass window
- Look for loose electron – candidate conversion
- (in the future might select conversion data sample using the constrain that the inv mass of e must account for the Z)

- 8/01/04

## Kinematics

- If the loose electron has large Et, the partner track belongs to the low pt range

- Partner track might
- belong to the low pt range

- Loose Ele from  conversion

-  conversion

- Tracking variables used to ID conversion

**Dxy**

**Cotg******

- ---- OBSP level
- ---- RECO level

- ---- OBSP level
- ---- RECO level

- 8/01/04

## Partner tracking efficiency 

-  Partner tracking efficiency
- track= probability of finding a partner track for a given seed electron
-  Calculated in MC
- Select Z events with a loose electron
- Identify conversion pair at OBSP level
- Match the loose central electron (“seed electron”) to OBSP electron (R<0.4)
- Look for a reconstructed track matched to the OBSP partner of the OBSP electron
- scale factor calculate based on CES information

- 8/01/04

## Scale factor (I)

*Need to select a data sample of conversions*
- For a given charge of the seed electron, the partner track has to be found in the “correct” side in φ
- Photon conversion pair: electron and positron have ~ same Z position at ay radius
- Combined into a criteria to select conversion candidates in data

- 8/01/04

## Scale factor (II)

- Select Z events with a loose electron
- For each given seed electron, look for the highest CES  cluster (unbiased or track based) close in Z and in the proper wedge
-  Z=(ZseedEle – Zces) < 4 cm if cluster in proper wedge

- Exploit CES information – unbiased and track based CES
- Unbiased: Ces Cluster seeded from strip/wire above threshold
- Track Based: Ces Cluster seeded from COT track
- Define the partner track finding efficiency:
- on event basis
- as the ratio of the number of events with track based conversions over the number of events with unbiased conversions
- Calculated in both data and MC – take ratio of the efficiencies

- 8/01/04

## Scale factor (III)

*Preliminary results*
- Need to run over the data – need higher statistic sample
- No background substraction
- Background: prompt electrons, fake electrons
- Do not expect large contamination of prompt electrons in Z events
- Fake electrons can be estimated (need to be consistent when calculate the fake rate itself)
- Any kind of background can be removed using CES info: the background will populate evenly the “correct” and the “wrong” wedge close to the seed electron

- 8/01/04

## Tagging cut efficiency

- cut = probability of tagging a conversion
- The “standard” tagging cuts are:
- 	Dxy < 0.2 cm
- 	cotg < 0.04
- Need to select a sample which is independent of the above tagging criteria
- Exploit CES information – track based CES

- Denominator of the tagging cut efficiency: number of candidate conversions
- Numerator of the tagging cut efficiency: number of candidate conversions tagged as conversion according to the applied cuts

- 8/01/04

## Is the conversion rate reproduced?

- Electron from conversions are _removed_
- Exploit PYTHIA sample (no ISR)

| CR | Tot backg | Data |
| --- | --- | --- |
| A | 0.3 | ---- |
| G | 1.9 | 3 |
| I | 3.2 | 3 |
| E | 1.2 | 1 |
| A2 | 0.03 | 0 |
| F | 0.09 | 0 |
| H | 0.07 | 0 |
| J | 0.22 | 1 |
| Z | 5.4 | 5 |

- 8/01/04

## Checks

- (The fake rate is estimated WITHOUT removing conversion from the jet sample)
- Compare PYTHIA (FSR only) to BAUR (ISR+FSR)

| CR | Tot backg
(DY Pythia) | Tot backg
(DY Baur) | Data |
| --- | --- | --- | --- |
| A | 0.4 | 0.2 | ??? |
| G | 5 | 5 | 9 |
| I | 5 | 4 | 6 |
| E | 1 | 0.1 | 2 |
| A2 | 0.03 | 0 | 0 |
| F | 0.1 | 0 | 0 |
| H | 0.1 | 0.03 | 0 |
| J | 0.2 | 0.03 | 2 |
| Z | 7.3 | 5 | 10 |

| CR | Tot backg
(DY Pythia) | Tot backg
(DY Baur) | Data |
| --- | --- | --- | --- |
| 3 lep | 13 | 11 | 22 |
| mass | 6 | 6 | 12 |

- 8/01/04

## ISR-FSR contribution

| CR | PYTHIA | BAUR | PYTHIA |
| --- | --- | --- | --- |
| A | 0.100.04 | 0.050.02 | 0 |
| G | 1.640.18 | 1.30.1 | 0.60.1 |
| I | 2.240.21 | 1.80.1 | 0.40.1 |
| E | 0.250.07 | 0.070.02 | 0.030.02 |
| A2 | 0 | 0 | 0 |
| F | 0.040.03 | 0 | 0 |
| H | 0.060.03 | 0 | 0.020.02 |
| J | 0.060.04 | 0.0090.009 | 0 |
| Z | 2.90.2 | 1.970.13 | 0.50.1 |

- Compare PYTHIA(FSR) and BAUR(ISR_FSR)
- with **no generator** **level cuts** and with the **same generator level cuts**

- BAUR:
**Photon pt > 5 GeV **
- R > 0.2
- M leptons > 20 GeV
- M leptons + photon > 20 GeV

- 8/01/04

## Summary

- 6.1 data validation (done)
- Run dependence now became task of lum group – just cross checking
- _Additional 440 pb__-1_ already ntuplized, run over it and confirm agreement in the control regions
- When available, will show the validation of the Muon Geom in 6.1 at Simulation Meeting
- Conversion (procedure is set)
- Need to generate another sample ?
- More comparison using CdfEm
- Run over high stat data sample (check B group)
- For Winter conferences, use current _5.3 MC and 6.1 data_
- By end of the year,
- Scale factors and trigger eff should be available (Top and MultiLepton group)
-      (will cross check the results of the trigg eff – little bit of coding is needed)
- Fake rate (Beate?)
- 	I will try to look at that
- Jan., run with new scale factors and fake rate
- Febr., sysematics and blessing
- Moriond, second half of March
- Publication with the results shown at Moriond

- 8/01/04

## Back up

- 8/01/04

## T+C results 

| nev | DiBoson | tt | DY | Fake | Tot | Susy | S/√B |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 3 leptons | 1.13
0.02 | 0.005
0.003 | 4.85
0.3 | 2
1 | 8.02
0.32 | 0.91
0.03 | 0.32 |
| Mass cut | 0.14
0.01 | 0 | 1.90.2 | 0.4
0.2 | 2.45
0.20 | 0.81
0.03 | 0.52 |
| Jet Cut | 0.14
0.01 | 0 | 1.80.2 | 0.4
0.2 | 2.36
0.19 | 0.80
0.03 | 0.52 |
| Met Cut | 0.01
0.01 | 0 | 0.097
0.04 | 0.12
0.06 | 0.32
0.04 | 0.7
0.03 | 1.2 |

- T+C results

- 8/01/04

## T+C control regions - dimuon

| CR | Fake (SS) | TOT MC | TOT | DATA |
| --- | --- | --- | --- | --- |
| A | 4 x 1.5 = 6 | 77 2 | 832 | 95 |
| G | 0 | 12918 | 12918 | 1319 |
| I | 0 | 799722 | 799722 | 7866 |
| E | 0 | 1983 | 1983 | 204 |
| A2 | 0 | 8.20.5 | 8.20.5 | 14 |
| F | 0 | 231 | 231 | 29 |
| H | 0 | 151 | 151 | 28 |
| J | 0 | 952 | 952 | 96 |
| Z | 0 | 922324 | 922824 | 9061 |

- 8/01/04

## Slide 31

| CR | Fake  | TOT MC | TOT | DATA |
| --- | --- | --- | --- | --- |
| A | 0.12
0.06 | 0.20
0.04 | 0.32
0.04 | BLIND |
| G | 0.18
0.09 | 1.67
0.18 | 1.86
0.18 | 3 |
| I | 0.82
0.41 | 2.42
0.21 | 3.24
0.21 | 3 |
| E | 0.269
0.135 | 0.93
0.07 | 1.20
0.07 | 1 |
| A2 | 0.02
0.01 | 0.011
0.04 | 0.031
0.04 | 0 |
| F | 0.033
0.0016 | 0.06
0.03 | 0.09
0.03 | 0 |
| H | 0.0154
0.007 | 0.06
0.03 | 0.07
0.03 | 0 |
| J | 0.16
0.08 | 0.07
0.04 | 0.22
0.04 | 1 |
| Z | 1.55
0.77 | 3.86
0.25 | 5.41
0.25 | 5 |

- 8/01/04

## T+C control regions - dimuon

- Mass in G

- All dimuons

- 8/01/04

## T+C control regions - dimuon

- 2nd muon pT
- 	in G

- All dimuons

- 8/01/04

## Fake rate 

- Fake rate calculated without removing conversion electrons from the jet sample

- 8/01/04