Compact Muon Solenoid Surapat Ek-In École Polytechnique Fédérale de Lausanne

Transcription

1 Compact Muon Solenoid Surapat Ek-In École Polytechnique Fédérale de Lausanne

2 Outline Introduction Electromagnetic Calorimeter Muon Chamber Application Conclusion Outline 2

3 LHC Experiments ~ 100 m Introduction 3

4 CMS Collaboration Over 5000 active people 200 Institutes 46 Countries. Introduction 4

5 Physics Programs The Standard Model - Higgs Physics - Top Physics - B Physics - Heavy-Ion Physics Introduction Beyond the Standard Model - Dark Matter production - Extra Dimensions - Supersymmetry - Heavy Gauge Boson - Mini Black Hole - 5

6 Compact Muon Solenoid Compact - Small but dense! Muon - Specialize in detecting muons Solenoid - Use a large solenoid magnet Introduction 6

7 Compact Muon Solenoid Muon Positron Charged Hadron Neutral Hadron Photon Introduction th April 4,

8 Electromagnetic Calorimeter (ECAL) Principle - Detect particles which have electromagnetic interaction, e.g. charged particles. - Create EM shower which is composed of e- and. Dominant processes - Pair production ( ) - Bremsstrahlung (e-) Radiation Length Extract from a lecture note by D. Bortoletto, U. of Oxford ECAL 8

9 Electromagnetic Calorimeter (ECAL) Simple Shower Model - Assume that E0 > Ec - Electron losses ~ 63 % of its initial energy after X0 - After passing t = x/x0, the remaining energy is E(t) = E0/2t - A particle stops if E < Ec = E0/2t,max - Example, Extract from a lecture note by D. Bortoletto, U. of Oxford ECAL 9

10 Electromagnetic Calorimeter (ECAL) CMS ECAL PbWO4 (X0 = 0.89 cm). ~ 23 cm in length. 61,200 crystals in the barrel section. 7,324 crystals in each of endcaps. ECAL 10

11 Muon Chamber Drift tube chambers (DTC) - Barrel section DTs Cathode strip chambers (CSC) - Endcap section CSCs track Resistive plate chambers (RPC) - Between DTC and CSC RPCs Layout of Muon System of CMS detector CMS Physics Technical Design Report Muon Chamber 11

12 Muon Chamber High energy muon mostly loses energy via ionisation. η < 1.2 Low muon rate. Relatively small background. 85% Ar and 15% CO2 B field is mostly uniform with strength below 0.4 T. Signals are used to calculate momentum of muon from its curvature. 0.9 < η < 2.4 Higher muon rate. High background. 50% CO2 40% Ar, and 10% CF4 B field is strong and non-uniform. Signals are used to calculate momentum of muon from its curvature. CSC has faster response time to deal with large BG. Resistive Plate Chambers - Act as an additional triggering detector system. Double-gap chambers, operating in avalanche mode to ensure reliable operation at high rates. Locate between DTC and CSC upto η = 1.6 Provide a fast, independent trigger. Extract from CMS Technical Design Report, and arxiv: Muon Chamber 12

13 Higgs Event Application 13

14 Monojet Event Application 14

15 Monojet Event Application 15

16 Conclusion Compact muon solenoid or CMS is a multipurpose detector to study validity of the Standard Model and search for new physics. Electromagnetic Calorimeter is used to absorb energies of particles that can interact through an EM interaction by creating EM shower. Muon Chamber is responsible for detecting muons from its ionization in gas detector. Conclusion 16

17 Thank you for your attentions! Any questions?

18 BACKUP

19 Monojet Event Journal of Physics: Conference Series 645 (2015) Backup 19

20 Magnetic Field Backup 20

21 DTC Backup 21

22 CSC Backup 22

23 RPC Backup 23