the cms muon detector
DESCRIPTION
The CMS Muon Detector. Searching for New Physics with High Energy Muons. Thomas Hebbeker Aachen July 2001. Outline. LHC and CMS energy, luminosity, background discoveries with muons muons in CMS detectors for muons Aachen muon project. LHC at CERN. 27 km circumference. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/1.jpg)
The CMS Muon Detector
Thomas HebbekerAachen July 2001
Searching for New Physics with High Energy Muons
![Page 2: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/2.jpg)
Outline
• LHC and CMS
• energy, luminosity, background
• discoveries with muons
• muons in CMS
• detectors for muons
• Aachen muon project
![Page 3: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/3.jpg)
LHC at CERN
Large
Hadron
Collider
27 km circumference
14 TeV c.m.e. (p p)
1200 TeV (Pb Pb)
p + p A + A
no antiparticles !
p p
![Page 4: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/4.jpg)
LHC
![Page 5: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/5.jpg)
LHC superconducting magnets
8.3 T 1.9 K 14.3 m 1232 x
![Page 6: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/6.jpg)
Center of Mass Energy
Relevant:center of mass energy of colliding constituents (q, g)
Required:
capability to produce new particles with masses up to 1 TeV !
s
p p
gluon
quark
Rough estimate:
Need:
ss 3
1
2
1
TeVTeVs 14126
s
![Page 7: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/7.jpg)
Cross Section and Luminosity
Total inelastic cross section
LN
Event rate
Pointlike cross section
p
p2252 1010 cmfm
2362
10 cms
BACKGROUND
SIGNAL
strong
electroweak
scmL //10 234 huge background !
particles /s1110100 particles /collision
> 1/hour
![Page 8: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/8.jpg)
Cross Sections
at Hadron Colliders
![Page 9: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/9.jpg)
CMS
Compact
Muon
Solenoid
diameter = 22 m 15 m
weight = 14500 t
Excellent signaturefor new physics
magnet type
length = 42 m 22 m
B
![Page 10: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/10.jpg)
CMS Detector
![Page 11: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/11.jpg)
Muon
Discovery: 1933 (Kunze), 1937 (Anderson, Neddermeyer)
s = ½
m = 0.106 GeV
= 2.20 s
Decay length:
L = c ~ E/m c E = 1 TeV:
L ~ 6000 km „stable“
ee
ee
Rabi: „Who ordered that ?“
e m600
![Page 12: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/12.jpg)
Cosmic Rays =
Atmospheric Muons
smmuons //200 2
= 0.5 mSv = 50 mrem
![Page 13: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/13.jpg)
Muons and Discoveries - Examples
Tau Lepton:
Bottom
quark:
seee '
SLAC 1975
Martin Perl et al.
Fermilab
1977
Leon
Lederman
et al.
Ap
bb
9.5 GeV
Upsilon
![Page 14: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/14.jpg)
New Physics at the LHC ?
Higgs boson:
![Page 15: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/15.jpg)
New Physics at the LHC ?
Supersymmetric Particles:
Chargino :
(partner of W)
Neutralino :
(partner of Z,)
Smuon :
(partner of muon)
![Page 16: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/16.jpg)
Hadron Colliders and Muons
Background (frequent):
strong interaction
-> quarks, gluons
( LHC: ~ 20 p – p collision events per bunch crossing )
Interesting events (rare):
electroweak processes,
decays of heavy particles
-> Leptons
![Page 17: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/17.jpg)
Hadron Colliders and Muons
one bunch crossing
(= 20 events superimposed):
inside detector
high energy
high energy
B
abso
rber
![Page 18: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/18.jpg)
Particle Detection
![Page 19: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/19.jpg)
Muon Properties NO strong interaction
electromagnetic interaction:
• NO (little) radiation
• ionisation
long lifetime
GeVm 106.0
energy loss negligible if
m large
decay length exceeds 100 m if
m small
e
no good
no g
ood
weak interaction
muon mass
![Page 20: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/20.jpg)
Higgs event in CMS tracker
![Page 21: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/21.jpg)
Higgs event in CMS tracker
![Page 22: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/22.jpg)
Higgs event in CMS tracker
![Page 23: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/23.jpg)
Higgs event in CMS tracker
![Page 24: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/24.jpg)
Higgs event in CMS
![Page 25: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/25.jpg)
Higgs event in CMS
![Page 26: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/26.jpg)
The CMS Muon Detector
![Page 27: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/27.jpg)
The Central CMS Muon Detector
![Page 28: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/28.jpg)
The CMS magnet
B = 4 T
superconducting coil
yoke
yoke
yoke
yoke
yoke
m
m
B = 1.5T
![Page 29: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/29.jpg)
The Central CMS Muon Chambers
muon
2 m
30 c
m
2 x 4 layers
„bending“
4 layers
„nonbending“drift cell
honeycomb layer
![Page 30: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/30.jpg)
The Drift Cell
drift region
v = 5.7 cm / s ~ constE ~ 2 kV/cm ~ const
amplification
E ~ 1/r -> 150 kV /cm
distance = time/v
m 250~
2.5m
distance+3600
V+1800 V
-1800 V 5
0 e
510~A
50m
Q ~ 500 fC -> amplifier
![Page 31: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/31.jpg)
(Transverse) Momentum Measurement
B field + coordinate measurements + vertex
constraint: TeV
p
p
p
%20
multiple scattering (iron,calorimeters):
muon detector alone:
%8
3.5
m
precision m100
iron, B
T5.1
vertex (interaction point)
m20
0
![Page 32: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/32.jpg)
CMS Muon (transv.) Momentum Resolution
![Page 33: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/33.jpg)
Chamber Production in Aachen
![Page 34: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/34.jpg)
Chamber Production Experts
![Page 35: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/35.jpg)
Chamber Gluing
![Page 36: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/36.jpg)
Layer with I-Beams, Wires and End Pieces
4 cm
![Page 37: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/37.jpg)
Measurement of Wire Position
CCD camera
resolution = few microns
![Page 38: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/38.jpg)
Determination of Wire Tension (3 N)
![Page 39: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/39.jpg)
Yoke: Installation of first wheel
![Page 40: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/40.jpg)
Outlook
• Muon chamber production:
– started 2001,– first chambers will be installed in 2002
• LHC and CMS will start data taking in 2006
... Higgs ...
... chargino ... stop ... smuon...
... ...
... extra dimensions ...
... tohu ... vabohu..
... gravitons ...
? ?
![Page 41: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/41.jpg)
Muons and CMS
• muons from new particles
• muons from W decays
• muons from bottom decays
• low energy hadron decay products
• cosmic muons
collision rate: 40 MHz
100 Hz
100 kHz
> 1 MHz
10 kHz
transverse momenta > 3 GeV: << 1 Hz ?
TRIGGER: transverse momenta > 20 GeV:
1 kHz
Background (central detector):
hadron „punchthrough“
neutron induced )( * eAAn
2/10 cmHz
![Page 42: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/42.jpg)
Electron Drift in Gas
typical values:
= 3 m = 30 ps
E = 1 kV/cm v = 5 cm/s
![Page 43: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/43.jpg)
Avalanche in Wire Chamber
E ~ 1/r
d = 50 mm
avalanche very close to wire
![Page 44: The CMS Muon Detector](https://reader037.vdocuments.us/reader037/viewer/2022102908/56812bc7550346895d9012d5/html5/thumbnails/44.jpg)
Muon mean timer