# Presentation: 415395

## Computing Performance

**September 14****th**** 2005**

**Dave Waters, University College London**

**Computing Performance**

- Run II Computing Review : CDF Software Status

- 9/14/05

**Notes:**
online <-> offline : offline not a constraint for CDF
Add lepton ID to bullet

## Tracking Performance

_**C**__entral __**O**__uter __**T**__racker_
- The heart of CDF : the key to tracking and setting of energy/momentum scales.
- Extremely efficient : 99.6 % (isolated); > 96% (non-isolated) particles.
- With recent improvements (post-pattern recognition hit finding), algorithms stable and performing well at least to ~ 21032 cm-2 s-1
- New alignment : wire positions to 10 m.

**Tracking Performance**

- Run II Computing Review : CDF Software Status

- 9/14/05

**Notes:**
Replace fast simulation with full GEANT simulationn ? Backup plot from Greg.

## Forward Tracking & Lepton ID

- all tracks :
-  inside-out
-  silicon stand-alone

- forward electron tracks (seed track finding using calorimeter info)

- electrons with no track requirement

- ||

- Efficiency

**NIM A538 (2005) 249**

- Run II Computing Review : CDF Software Status

- 9/14/05

**Notes:**
Make flat efficiency line curve ...
Give NIM reference for tracking curve

## Forward Tracking & Lepton ID

- _W (Lepton) Charge Asymmetry_
- Input to PDF’s

- Can also optimize algorithms and/or cuts for resolutions rather than efficiency :
-  pT
-  lifetime measurements
-  charge identification

- Run II Computing Review : CDF Software Status

- 9/14/05

## Taus

- Complex high-level object, incorporating :
- tracking
- calorimetry
- shower-max & 0 reconstruction

- _Offline_: ID algorithms largely converged. Some differences due to demands of different analyses.
- _Online_: suite of tau triggers (leptonic + hadronic decay modes).
*Z*+-  calibration signal established.
- Very important search mode :

- Run II Computing Review : CDF Software Status

- 9/14/05

**Notes:**
Backup slide on efficiencies & fake rates from YKK
Fraction of reconstructable taus : Rutgers notes

## Particle ID : dE/dx

**track momentum (GeV/c)**

**dE/dx (arbitrary units)**

***K***

***p***

***d***

- 96 charge measurements allow excellent COT particle ID
- well tested & packaged CDF-standard particle ID code corrects for detector inhomogeneities and time variation : *tools developed for one analysis* (heavy-flavor physics) *readily adopted by other analyses* (baryon production in min-bias events).
- silicon dE/dx has been demonstrated (adds very little to COT for most analyses)

- Run II Computing Review : CDF Software Status

- 9/14/05

**Notes:**
Add a slide on complementarity of dE/dx and ToF - BPAK ???
Explicit ToF slide ...
One more iteration on alignments (new COT alignments will go into offline version 7)
Most b-tagging algorithms currently using L00

## Particle ID : Time of Flight

**Particle ID : Time of Flight**

- Large effort to derive corrections (as functions of track position, angle, particle type, etc.), calibrations & develop accurate simulation.
- Close to design resolution of 100 ps.
- Combined (complementary) particle ID :

- Run II Computing Review : CDF Software Status

- 9/14/05

## Flavour Physics

**Flavour Physics**

- _Example :_   ***B******S***
- Demanding analysis bringing together all the aspects of tracking & particle ID :
- secondary vertex and lifetime determination
- dE/dx
- time-of-flight

- _Future :_
- A few low level improvements :
- one more SVX & relative alignment iteration after feeding in latest COT alignment
- Mainly high level algorithm developments :
- flavor tagging
- understanding of backgrounds
- etc ...

- Run II Computing Review : CDF Software Status

- 9/14/05

**Notes:**
Natural width versus resoluion ?
More examples on this slde ?
Find out status of L00

## Calorimeter Performance

- New Run IIb detectors already incorporated into production reconstruction :
- new central pre-shower detector
- EM timing
- Further development will be in higher level (user/ntupling) realm.
- Recent progress has been operational - fast calibrations for production :

**Calorimeter Performance**

- Run II Computing Review : CDF Software Status

- 9/14/05

**Notes:**
Plots showing increase in resolution with final calibrations ? (where were these)
Check number of weeks for calibration generation
CPR reco & EM-timing already running in production, remain to be validated for use in analysis - Production already stable with respect to these

## Jets

- Jet

- bb invariant mass (GeV)

- 10% resolution

- _Jet energy scale uncertainty:_
- precision measurements (Mtop) & searches (Higgs)
- now ~2.5% uncertainty for jets in top decays
- further improvements:
- generators, higher order QCD
- better scale for ET > 100 GeV region
- complete by end of this year
- _Jet energy resolution:_
- searches (Higgs, ...)
- currently 17%, goal 10-11% (@ MH =120GeV)
- further improvements:
- combine track, calorimeter Info: 2%
- expand cone size: 2%
- b-jet specific corrections:1-2%
- better algorithms: 1-2%
- complete by spring 2006

**improvements all**
**“****post-production”**

- Run II Computing Review : CDF Software Status

- 9/14/05

**Notes:**
Algorithm refinements (combining track-calorimeter information) would be done at ntuple(ing) level, wouldn’t reprocess using production.

## B-Tagging

**Better algorithms: Neural Network**

**Forward**

**Loose (1.8% mistag)**
**Tight (0.6% mistag)**

**Sec. Vertex B Tagging**

- Importance of 3rd generation for top physics, Higgs & searches.
- Different analyses can pick points in space of *efficiency vs. fake-rate*.
- Approaching design performance, but not there yet.
- Other taggers also becoming mature :
- soft muons
- jet probability
- Ongoing efforts :
- increased forward acceptance
- soft electron tagger
- neural net based taggers

- Run II Computing Review : CDF Software Status

- 9/14/05

**Notes:**
Efficiency per b-jet or per top event ?
True that approaching design efficiency (50%) ?

## Performance at High LINST

- _Low-level :_
- COT tracking most vulnerable to high occupancies :
- hit recovery maintains good efficiency & resolution up to ~ 21032 cm-2 s-1
- no evidence for any loss in efficiency in current dataset
- will monitor performance closely as peak luminosities further increase

**2********10****32**** cm****-2**** s****-1  ****: <N****VTX****> ~ 6**

- _Higher-level :_
- Important analysis variables are f(NVTX) :
- isolation energies
- underlying event corrections
- Check for non-linearities at very high-L
- Need good simulation (see later)
- Use observables less dependent on LINST

- Run II Computing Review : CDF Software Status

- 9/14/05

**Notes:**
So far no visible loss in efficiency up to 2
We will continue to monitor closely ...
Modify label
Saturation comment not clear
Building analysis techniques to be insensitive/adaptive to effects of L_INST 

## Design Analyses for High LINST

- _e.g. W Mass Measurement_
- Missing-ET resolution becomes progressively worse at higher instantaneous luminosities.
- Lepton pT resolution almost unaffected.
- Switch over point is ~ 11032 cm-2 s-1
- Data taken at all luminosities will be useful.

**confidence in algorithms & simulation to make these extrapolations**

- Run II Computing Review : CDF Software Status

- 9/14/05

**Notes:**
Should we have this slide ... 
Confidence in algorithms etc. is sufficiently high that we can do this ...

## 

- Increased occupancy leads to higher processing times
- Expect linear ( ***N*****TRK**) + combinatoric terms ( ***N*****TRK****k**)

- Still dominated by linear growth term
- Manageable CPU resource requirements for lifetime of experiment

**<L> ≈ 0.4 ******** peak-L**

- Run II Computing Review : CDF Software Status

- 9/14/05

**Notes:**
Not average luminosities : peak luminosities
Peak->average for a store : scale factor of ~40%

## Online Implications

**Online Implications**

- Offline software & algorithms are used online :
- CPU performance more critical
- event size critical
- dirtier environment

- Strategy :
- Optimization
- CPU & I/O trade-offs
- Remove unnecessary reconstruction    (e.g. z-side clustering)
- Different thresholds online & offline
*Different algorithm online*

**planning to avoid this !**

**event size (kB)**

- Run II Computing Review : CDF Software Status

- 9/14/05

**Notes:**
What are the two curves ...

## Simulation Refinements

- Simulation infrastructure is now very stable.
- Material tunings converging                  (good to ≤ 15%)
- Recent improvements to tracking simulation:
- t0 distribution
- hit resolutions
- Some work needed to include and tune description of new detectors (CPR).
- Certain analyses use fast simulations; can be validated against full GEANT simulation.

- Run II Computing Review : CDF Software Status

- 9/14/05

## Simulation Refinements

_**New**__ : run-dependent Monte Carlo_
- Tracks changes detector configuration.
- Simulate the effects of higher instantaneous luminosities through the addition of overlapping min-bias events : Poisson distributed according to ***L***INST (run).
- MC run list chosen to reproduce ***L***INST distribution of data.
- MC datasets easily *extended* (not *replaced*) as further collider data is accumulated.

***L*****INST**** (********10****32****)**

***L*****INST**** (********10****32****)**

**       ****# tracks         **

**       ****# vertices      **

- Run II Computing Review : CDF Software Status

- 9/14/05

**Notes:**
Timing information for MC ?
Add a few more words on how this is done
Mention extendibility of Monte Carlo resources
Manfred/Vivek X-ray pictures

## Conclusions & Outlook

- Low-level software & algorithms development is approaching asymtote.                   Only a few exceptions :
- Forward tracking  enhanced lepton ID, b-tagging performance etc.
- Of course, there are cautions :
- Effect of increased instantaneous luminosity : we have planned for this, but extrapolations are non-linear with sometimes large uncertainties
- (Un)-anticipated changes in detector configuration & performance

- High-level developments : much more work to be done, but mainly in user-domain.     For example :
- Final sets of jet & other corrections.
- Advanced analysis techniques - neural networks etc.

- CDF production reconstruction is ready for 1fb-1 analyses ... and beyond.

- Run II Computing Review : CDF Software Status

- 9/14/05

**Notes:**
Forward tracking -> muons, b-tagginng etc.
Repeat that it’s not the RECONSTRUCTION that is limiting productivity at all (with this one exception maybe)

## Backup

- Hadronic Tau

- Jet mis-id (%)            efficiency (%)

- Evis(GeV)

- Ejet (GeV)

- Run II Computing Review : CDF Software Status

- 9/14/05