1. Jeremy andrea, marco musich ,tatjana susa, Stefano mersi
TEE CHIN ZHE (UM)
Automatic measurement of track reconstruction efficiency for data quality monitoring in the CMS experiment
Tee Chin Zhe
Jeremy andrea, marco musich ,tatjana susa, Stefano mersi
Ep – ucm
06 JUNE 2019

2. CERN SUMMER STUDENT SESSION 2019
TEE CHIN ZHE (UM)
About Myself
ChinZhe Tee
Malaysia
University of Malaya, Kuala Lumpur
Physics, Bachelor of Science
Analysis, Particle phy. ,C++, ROOT, CMSSW (?)
Apply to Europe/China/Taiwan for MSc.
Love and enjoyed everything in CERN!!
but I miss Asian food and nightlife in Malaysia though :’(
7/8/2019
CERN SUMMER STUDENT SESSION 2019

3. CERN SUMMER STUDENT SESSION 2019
Track Reconstruction
Associate hits in detector components to reconstruct the
trajectory of charged particles.
Estimation of the charged particle 𝒑 𝑻 when magnetic field is present.
Primary vertex and secondary decay vertices identifications.
Identify events with particles of long lifetime, i.e. b, τ.
Muon as the “benchmark” to monitor the track reconstruction efficiency.
Bartz, E., Chaves, J., Gershtein, Y., Halkiadakis, et. al. (2017). FPGA-Based Tracklet Approach to Level-1 Track Finding at CMS for the HL-LHC. EPJ Web of Conferences, 150, doi: /epjconf/
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CERN SUMMER STUDENT SESSION 2019

4. Motivation of this project?
CMS has a comprehensive Data Quality Monitoring (DQM) system. When a subdetector behaves abnormally, it is reflected in measured or reconstructed properties.
Presence of minor failures“How’s the data quality impacted?”
Require QUICK AND SIMPLE methods to estimate the effects  AUTOMATIC MEASUREMENT  not necessary need to be very precise.
A specific case to study in DQM : 𝒁  𝝁 + 𝝁 −
𝜀 𝜇 = 𝜀 𝑡𝑟𝑎𝑐𝑘 ∙ 𝜀 𝑟𝑒𝑐 ∙ 𝜀 𝑖𝑠𝑜 ∙ 𝜀 𝑡𝑟𝑖𝑔
7/8/2019
CERN SUMMER STUDENT SESSION 2019

5. CERN SUMMER STUDENT SESSION 2019
Tag and Probe Method
TAG = Muon that is fully reconstructed from combining Muon Chamber and Tracker (GUIDE)
PROBE = Muon that is reconstructed in the Muon Chamber (THIS IS WHAT WE WANT TO STUDY)
EFFICIENCY = ratio of a TAG muon to the PROBE muon
“Tag” = Global Muons
2. “Probe” = StandAlone Muons (stA Muons)
Select the high 𝑝 𝑇 Global Muons, combine with stA
Muons to calculate the 𝑀 𝑍 𝑖𝑛𝑣 .
Associate the stA Muons with tracks and select those
with ∆𝑅 < i.e. 0.1
5. ε 𝑟𝑒𝑐 = # 𝜇 𝑠𝑎𝑡𝑖𝑠𝑓𝑖𝑒𝑑 (4) 𝐼𝑛𝑣. 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑍 𝑓𝑟𝑜𝑚 (3)
Plot in different kinetic/geometric variables : η & 𝑝 𝑇
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CERN SUMMER STUDENT SESSION 2019

6. ε 𝑟𝑒𝑐 = 96.65% = # 𝜇 𝑠𝑎𝑡𝑖𝑠𝑓𝑖𝑒𝑑 (4) 𝐼𝑛𝑣. 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑍 𝑓𝑟𝑜𝑚 (3)
Construct the Z boson invariant Mass.
Events with
AT LEAST 1 Global muons.
AT LEAST 2 stA muons.
Select Z mass window of 85< Z <105
ε 𝑟𝑒𝑐
= # 𝜇 𝑠𝑎𝑡𝑖𝑠𝑓𝑖𝑒𝑑 (4) 𝐼𝑛𝑣. 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑍 𝑓𝑟𝑜𝑚 (3)
= %
These muons are used to study the efficiencies.
Select the “Tag”.
Track and stA muons selection ΔR < 0.1
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CERN SUMMER STUDENT SESSION 2019

7. CERN SUMMER STUDENT SESSION 2019
Expected Analysis
Collaboration, T. C. (2014). Description and performance of track and primary-vertex reconstruction with the CMS tracker. Journal of Instrumentation, 9(10). doi: / /9/10/p10009
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CERN SUMMER STUDENT SESSION 2019

8. CERN SUMMER STUDENT SESSION 2019
What’s next?
Examine the efficiencies using different kinematics/geometric variables, bin-by-bin.
Estimate the efficiency from simulation.
Compare the simulation and actual data efficiency.
Studies on statistics: to check are there enough Z boson for each run for analysis.
Learn how to implement more realistic conditions (i.e. Using χ 2 to determine the quality of
muons instead of selecting the highest 𝑝 𝑇 muons.)
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CERN SUMMER STUDENT SESSION 2019

9. CERN SUMMER STUDENT SESSION 2019
THANK YOU FOR LISTENING!
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CERN SUMMER STUDENT SESSION 2019

10. CERN SUMMER STUDENT SESSION 2019
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CERN SUMMER STUDENT SESSION 2019