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Tuning the HF Calorimeter GFlash Simulation Using CMS Data Jeff Van - - PowerPoint PPT Presentation

Dec 17, 2022 283 likes •812 views

Tuning the HF Calorimeter GFlash Simulation Using CMS Data Jeff Van Harlingen 1 Rahmat Rahmat 2 Eduardo Ibarra Garca Padilla 3 1 Madison Junior High School (NCUSD 203) 2 Mid-America Christian University 3 Universidad Nacional Autnoma de Mxico

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SLIDE 1

Tuning the HF Calorimeter GFlash Simulation Using CMS Data

Jeff Van Harlingen1 Rahmat Rahmat2 Eduardo Ibarra García Padilla3

1Madison Junior High School (NCUSD 203) 2Mid-America Christian University 3Universidad Nacional Autónoma de México

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SLIDE 2

Outline

  • LHC and CMS Description
  • Particle Collisions
  • The Higgs Boson
  • HF Calorimeter at CMS
  • GFlash Speed and Accuracy Tuning
  • Future Applications
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SLIDE 3

Large Hadron Collider (LHC)

  • Located at CERN in Switzerland
  • Four major experiments (CMS, ATLAS, ALICE,

and LHCb)

  • The LHC is a 27-km ring lined with

superconducting magnets

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SLIDE 4

Large Hadron Collider (LHC)

  • Two particle-beams are accelerated close to the

speed of light

  • Collisions between these high-energy beams,

create particles that could tell us about the fundamental building blocks of the universe

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SLIDE 5

Compact Muon Solenoid (CMS)

  • 14,000 Ton Detector
  • One of the largest science collaborations in

history:

  • 4,300 physicists, engineers, technicians, etc.
  • 182 Universities and institutions
  • 42 countries represented
  • 21 meters long
  • 15 meters wide
  • 15 meters high
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SLIDE 6

Compact Muon Solenoid (CMS)

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SLIDE 7

Compact Muon Solenoid (CMS)

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SLIDE 8

Compact Muon Solenoid (CMS)

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SLIDE 9

Solenoid

Creates 4 Tesla magnetic field to bend the path of particles

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SLIDE 10

Silicon Tracker

Measuring the positions of passing charged particles allows us to reconstruct their tracks.

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SLIDE 11

Electromagnetic Calorimeter

Measure the energies of electrons and photons

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SLIDE 12

Hadronic Calorimeter

Measure the energies of hadronic particles (Pions)

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SLIDE 13

Muon Chambers

Tracks Muon Trajectories

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SLIDE 14

Hadronic Forward Calorimeter

Measure the energies of hadronic and electromagnetic particles

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SLIDE 15

How do we detect particles?

“Just as hunters can identify animals from tracks in mud or snow, physicists identify subatomic particles from the traces they leave in detectors”

  • CERN
  • Accelerators
  • Tracking Devices
  • Calorimeters
  • Particle ID Detectors
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SLIDE 16

Step-by-Step Collision

  • 1. Accelerate particles to near the speed of light

using electromagnetic fields.

  • 2. Physicists can bend the beam using

superconducting magnets.

  • 3. Collide particles in four specific locations.

Sub-atomic particles are ejected.

  • 4. Normally particles travel in a straight line.

Using magnetic fields, the particle paths can be

  • curved. (Only for charged particles)
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SLIDE 17

Step-by-Step Collision

  • Particles that

curve a lot have low momentum.

  • Particles that

curve just a small amount have very high momentum

(Old Bubble Chamber Method)

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SLIDE 18

Step-by-Step Collision

  • 1. Sub-atomic particles also enter calorimeters.
  • 2. These are designed to absorb and measure

the energy of particles.

  • 3. Made from high-density materials.
  • 4. Electromagnetic Calorimeters can identify

electrons and photons.

  • 5. Hadronic Calorimeters can identify particles

made from quarks (pions, neutrons, protons)

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SLIDE 19

Step-by-Step Collision

  • 1. Physicists can also measure Cherenkov light

from particles to help determine their momentum.

  • 2. In a vacuum, nothing moves faster than the

speed of light. However, in other materials (like water), high-energy particles can travel faster than light.

  • 3. “It is the optical equivalent to a sonic boom”
  • Explain it in 60 Seconds

(Symmetry Magazine)

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SLIDE 20

Cherenkov Radiation

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SLIDE 21

Cherenkov Radiation

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SLIDE 22

Cherenkov Radiation

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SLIDE 23

Combining Results

  • Physicists use the combination of all these

methods to learn about the fundamental building blocks of the universe.

  • Discoveries on many particle accelerators and

detectors in the past have led to the Standard Model.

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SLIDE 24

The Standard Model

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SLIDE 25
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SLIDE 26

More To Be Discovered?

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SLIDE 27

What about the Higgs Boson?

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SLIDE 28
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SLIDE 29

What about the Higgs Boson?

July 4, 2012

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SLIDE 30

Fermilab Summer 2014 - HFCAL

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SLIDE 31

Hadronic Forward Calorimeter (HF)

Hadronic Forward Calorimeter(HF) is placed about 11 m from interaction point and has 3 <||< 5. There is no

  • ther calorimeter in front of HF so that

HF is a very good place to study Gflash.

Rahmat

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SLIDE 32

HF Calorimeter

Particles Enter

LONG FIBERS SHORT FIBERS AND

Beam Collision

Light signal converted to electrical signal in Photo Multiplier Tubes (PMT)

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SLIDE 33
  • Long fibers (165cm)
  • Short fibers (143cm)
  • Alternating

steel and fiber structure in each wedge.

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SLIDE 34
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SLIDE 35

HF Calorimeter

  • Use LONG and SHORT Fibers to differentiate

shower from electromagnetic (e-) and hadronic particles (π+).

Rahmat

Particles Enter

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SLIDE 36

HF Calorimeter

Electron Positron Photon

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SLIDE 37

Fermilab Summer 2014

  • Goal was to improve the speed and accuracy
  • f the GFlash computer simulation using data

from CMS, Test Beam, and Shower Library.

  • Daily work included changing variables to test

accuracy and speed of the HF Calorimeter simulation.

  • Energy of the Electron and Pion (GeV)
  • Eta = pseudorapidity (η)
  • Φ = an angular measurement
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SLIDE 38

Fermilab Summer 2014

  • Increase the speed of the simulations by

removing particles such as soft neutrons (low energy).

  • These particles have low interaction rates.
  • Cut any interactions below 1.0-1.5 GeV to

achieve this.

  • Any particle below this threshold is “killed”

and we don’t collect further data on it

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SLIDE 39
  • E. Ibarra
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SLIDE 40

HF Calorimeter

  • E. Ibarra
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SLIDE 41

HF Calorimeter

  • E. Ibarra
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SLIDE 42

Fermilab Summer 2014

  • Final step was to tune very precise parameters

to reduce the discrepancy between test beam data and our simulation.

  • 10 parameters (variables) to change
  • 310 possible combinations = 59,049*
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SLIDE 43

Fermilab Summer 2014

  • G. Grindhammer and S. Peters
  • We assigned each parameter a letter. We then altered

the variables up or down in various combinations.

B A C D E F H G J I

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SLIDE 44

Fermilab Summer 2014

  • Check our simulation against the Test Beam data for

each combination of fibers.

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SLIDE 45

Fermilab Summer 2014

  • Use formulas to calculate the uncertainty and error

discrepancy from test beam data.

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SLIDE 46

Results

  • We were able to tune HF GFlash

simulations:

  • Reduced the error by 55%
  • Runs 76% faster
  • Achieved a 1.15% mean

discrepancy when compared to Test Beam Data

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SLIDE 47

What lies ahead?

Photons can create a shower of electrons and positrons that the HF Calorimeter can measure. Could be a signature of Higgs production.

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SLIDE 48

Looking for Non-Standard Model Higgs

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SLIDE 49

What lies ahead?

  • GFlash could be used in many other large

scale data analysis scenarios.

  • International Linear Collider
  • Muon Colliders
  • Other applications?
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SLIDE 50

References

  • “Performance of HFGFlash at CMS”, Rahmat

Rahmat, EPJ Web of Conferences, 49, 18805 (2013).

  • “Design, performance, and calibration of CMS

forward calorimeter wedges”, CMS-HCAL

  • Collaboration. Eur. Phys. J. C 53, 139-166

(2008)

  • http://home.web.cern.ch/about/how-detector-

works

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SLIDE 51

Photo References

  • https://cms-docdb.cern.ch/cgi-

bin/PublicDocDB/ShowDocument?docid=3045

  • http://home.web.cern.ch/topics/large-hadron-collider
  • http://physicsworld.com/cws/article/news/2011/nov/02/lhc-trials-

proton-lead-collisions

  • http://scienceblogs.com/startswithabang/files/2011/05/lhc-sim.jpeg
  • http://www.theinquirer.net/inquirer/news/1009715/lhc-start-

successful

  • http://www.purdue.edu/newsroom/general/2011/111216BortolettoC

MS.html

  • http://wordlesstech.com/2013/03/29/cms-particle-detector-open-

for-maintenance/

  • http://seedmagazine.com/portfolio/17_bubble-tracks.html
  • http://www-zeus.physik.uni-bonn.de/~brock/feynman/vtp_ws0506/