LL & MT, 3/9/2010
Validation of CLIC simulation and reconstruction tools
This list below defines the “deliverables” related to the software tools and their
readiness for the mass production and reconstruction of the CLIC detector
benchmark studies. The required studies apply to both CLIC_ILD and CLIC_SiD
with the respective reconstruction software chain proposed for the CDR.
One of the main aims is to evaluate the current performance for physics objects in the
following energy/angular ranges:
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Jets:
Electrons:
Muons:
Photons:
45 GeV – 1.5 TeV,
5 GeV – 1.5 TeV,
5 GeV – 1.5 TeV,
5 GeV – 1.5 TeV,
cos < 0.950
cos < 0.995
cos < 0.995
cos < 0.995
A further aim is to understand the ability of the current software tools to overlay
background and the impact of background on the event reconstruction, with the aim
of understanding what is feasible for the benchmark analyses and the likely CPU
resources.
The final aim is to start to define the requirements for event generation (numbers of
events and type) for the benchmark studies and to understand the CPU resources
required.
1. Particle Flow and Particle ID related to PFA
Aim: establish performance of particle flow reconstruction software in terms of jet
energy reconstruction and lepton identification efficiencies. The required studies are:
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Jet energy resolution at high energies (45 GeV – 1.5 TeV) overall and as a
function of cos [Angela for CLIC_ILD, Marcel for CLIC_SiD]. Plots:
o Plot of jet energy resolution vs energy for Zuds events;
o Plot of jet energy resolution vs cos for 45, 100, 250, 500, 1000, 1500
GeV jets.
PFA Reconstruction of Digital HCAL for CLIC_SID [? For CLIC_SiD].
Plots:
o Plot of hadron energy scale (mean reconstructed energy) for KLs;
o Plot of single hadron (KL) energy resolution [%] vs. energy;
o Plot of jet energy resolution vs energy for Zuds events.
Muon identification (reconstructed particle flow objects). Plots:
o Efficiency for isolated high-E muons (in e+e-  smuons) as a function
of cos [? for CLIC_ILD, ? for CLIC_SiD];
o Efficiency and Purity for muons in b-jets as a function of energy and as
a function of cos [Erik for ILD, ? for CLIC_SiD]. For 250, 500 and
1000 GeV jets.
Electron identification, including final state radiation
o Efficiency for isolated electrons (in e+e-  selectrons) as a function of
cos [? for ILD, ? for CLIC_SiD];
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o Efficiency and Purity for electrons in b-jets as a function of energy and
as a function of cos. For 250, 500 and 1000 GeV jets [?, ?].
Photon reconstruction: [Jacopo for CLIC_ILD, Peter Speckmayer for
CLIC_SiD].
o Photon identification efficiency as a function of energy and cos for
single photons (5 GeV – 1.5 TeV). [?, ?]
o Photon identification efficiency and purity as a function of energy and
cos for photons in 250, 500 and 1000 GeV jets. [?, ?]
2. Tracking performance
Aim: establish performance of the track reconstruction software over the full solid
angle. The required studies are:
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Tracking finding efficiency. Plots:
o Efficiency and fake rate (split tracks) for single muons as a function of
energy and angle. [? CLIC_ILD, ? for CLIC_SiD].
o Efficiency for single electrons. [? for CLIC_ILD, ? for CLIC_SiD].
o Track reconstruction efficiency versus angle (for different energy
ranges) in 250, 500, 1000 GeV jets. [? for CLIC_ILD, ? for
CLIC_SiD].
Momentum resolution. Plots:
o Momentum resolution for single muons as a function of energy and
angle. [? for CLIC_ILD, ? for CLIC_SiD].
o Momentum resolution for single electrons as a function of energy and
angle. [? for CLIC_ILD, ? for CLIC_SiD].
Impact parameter resolution. Plots:
o d0 and z0 resolution for single muons as a function of momentum and
angle. [? for CLIC_ILD, ? for CLIC_SiD].
Quantify CLIC_ILD track splitting issue (FullLDCTracking). Plots:
o Splitting rate in single muons (as above). [? for CLIC_ILD].
o Track splitting rate in 250, 500, 1000 GeV jets versus track energy
energy. [? for CLIC_ILD].
o False TPC/Si track merging rate in 250, 500, and 1000 GeV jets as a
function of track energy. [? for CLIC_ILD].
3. Flavour Tagging
Aim: establish performance of current flavour-tagging software and formulate a
strategy for its application to the benchmark studies. In the first instance the required
validation studies are:
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b-, c-, b/c- tagging efficiency and purity. Plots:
o Efficiency and purity curves for 45 GeV and 250 GeV jets for
comparison with ILC LoIs. [? for CLIC_ILD, ? for CLIC_SiD].
o Efficiency and purity curves for 500 and 1000 GeV in bins of cos. [?
for CLIC_ILD, ? for CLIC_SiD].
4. Monte Carlo Overlay Tools
Aims: establish current status of CLIC_ILD and CLIC_SiD overlay processors. [? for
CLIC_ILD, Christian for CLIC_SiD].
5. Beam-induced background related issues
Aim: demonstrate the viability of reconstructing events in the presence of
background.
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Incoherent pairs and tridents. Can the overlay and reconstruction software
cope with overlay and reconstruction of incoherent pairs and tridents.
o Assume overlay of full bunch-train in TPC
o Assume overlay of 40 BXs in Silicon detectors
o Numbers:
 Reconstruction time per event for 1 TeV Zuds events.
o Plots:
 Track finding efficiency versus momentum for 1 TeV Zuds
events.
hadrons
o Track reconstruction efficiency for full bunch train overlay in TPC
o Time-stamping strategy in PFA analysis
o Feasibility of overlaying full bunch-train of hadrons background
in benchmark studies. Need:
 Reconstruction time per event.
 Impact on PFA.
 Impact on track reconstruction efficiency.
6. Monte Carlo Performance
Aim: understand impact of range and energy cut-offs and benchmark MC
performance (seconds/TeV of visible energy).
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Use Z  uds events at 3 TeV as standard.
Understand impact of range/energy cuts from Geant4 team, CALICE and LoI
groups. [Angela]
Validate performance (Mokka and SLIC) as a function of range cut and
energy cutoff. Plots [Angela for CLIC_ILD, Christian for CLIC_SiD]
o Time versus range cut
o Time versus energy cutoff
o Impact on physics performance (muon momentum resolution, EM energy
resolution and jet energy resolution?)
7. Event Generation
Aims: agree on generators (baseline is Whizard for compatibility with ILC LoI
studies) and start to define event samples required for the benchmark analyses.
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Comparison of Whizard/Pythia with and without ISR/Beamstrahlung
[Stephane, Peter Schade]
Tuning of Pythia fragmentation and b-decay parameters. [?]
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Understand requirements for each benchmark analysis, i.e. desired numbers of
signal and SM background events. [Analysis teams]
Understand event generation requirements for CLIC_ILD and CLIC_SiD
benchmark studies [Frederic/Mark].