Transcript Korea-CMS Experiment Group

CMS Experiment at CERN LHC
Young-Il Choi
Sungkyunkwan University
(Hanyang Univ. 08.9.24 )
1
Prof. Young-Il Choi (Sungkyunkwan University)
EDUCATION:
- Ph. D. in Physics, (1982-1986) 1986
University of Pittsburgh, Pittsburgh, PA, USA
- M. S. in Physics, (1980-1982) 1982
University of Pittsburgh, Pittsburgh, PA, USA
- B. S. in Physics, (1974-1979) 1979
Seoul National University, Seoul, Korea
CAREER:
- Professor
(1997 )
- Associate Professor (1992 - 1997)
- Research Scientist (1989 - 1992)
- Research Associate (1986 - 1989)
Sungkyunkwan University
Sungkyunkwan University
Purdue University, IN, USA
Purdue University, IN, USA
RESEARCH:
- CMS Experiment at CERN, Switzerland (2000 – 2007 – )
- RENO Experiment, Korea (2006 – )
- Super Kamiokande Experiment , Japan (2002 - )
- BELLE Experiment at KEK, Japan (1997 - )
- ALEPH Experiment at CERN LEP, Switzerland (1995 - 1997)
- EOS-TPC Experiment at LBL HISS, USA (1989 - 1996)
- E735(Quark-Gluon Plasma) at FNAL Tevatron, USA (1986 - 1992)
- AFS(E808) Experiment at CERN ISR, Switzerland (1982 - 1986)
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Information for K-CMS LHC experiment
http://public.web.cern.ch
http://cms.cern.ch
http//www.cms-kr.org
Physics & High Technology 2008.05
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Overview
 CERN & LHC
 CMS Detector
 Korea-CMS Experiment Group
 Particle Physics Theory
 Life at CERN
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CERN & LHC
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CERN Member States
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CERN CMS Experiment
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CERN Site
LHC
SPS
CERN Site (Meyrin)
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LHC Detectors
General-purpose
Higgs
SUSY
??
Heavy Ions
Quark-gluon plasma
LHCf
B-physics
CP Violation
General-purpose
Higgs
SUSY
??
TOTEM
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Collisions at the Large Hadron Collider
7x1012 eV Beam Energy
1034 cm-2 s-1Luminosity
2835
Bunches/Beam
11
10
Protons/Bunch
Proton
7.5 m (25 ns)
7 TeV Proton
colliding beams
Bunch Crossing 4x107Hz
Proton Collisions109 Hz
e-
Parton Collisions
New Particle Production 105 Hz
(Higgs, SUSY, ....)
µ+
p
µ+
H
Z
c1-
µp
~
q
~
g
p
~
q
Z
q
µ-
ne
q
~
c20
q
p
m+
mc~1 0
10
- Injection test very successful
LHC timeline
1984
1987
12
1990
Workshop on a Large Hadron Collider in the LEP tunnel, Lausanne
Rubbia
“Long-Range
Planning
Committee”
recommends
Large Hadron Collider as the right choice for CERN’s future
ECFA LHC Workshop, Aachen
1992
1993
1994
1996
1998
General Meeting on LHC Physics and Detectors, Evian les Bains
Letters of Intent (ATLAS and CMS selected by LHCC)
Technical Proposals Approved
Approval to move to Construction (ceiling of 475 MCHF)
Memorandum of Understanding for Construction Signed
1998
2000
2004
2008
Construction Begins (after approval of Technical Design Reports)
LEP closes, LHC installation starts
Last experimental cavern (CMS) completed
LHC and experiments ready for first beam (Sep.10)
LHC inauguration Ceremony (Oct. 21)
p + p collisions (?)
The CMS Collaboration
CMS Collaboration
USA
37 Countries
184 Institutes
2930 Scientists and Engineers
Austria
Belgium
Finland
France
Germany
Greece
Hungary
Italy
Poland
Portugal
Slovakia
Spain
CERN
Switzerland
UK
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CMS Detector
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CMS – Compact Muon Solenoid
-Total weight : 12,500 t
-Overall diameter : 15 m
-Overall length : 21.6 m
-Magnetic field : 4 Tesla
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CMS Detector
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Transverse View of CMS
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“Swivelling the coil”
Coil is constructed
vertically but needs to be
horizontal!
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Standing in the coil – at 100K!
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The “Gothic Cathedrals of the 21st Century”
CMS detector 100m underground
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Particle Detectors
• Cannot directly “see” the collisions/decays
– Interaction rate is too high
– Lifetimes of particles are too small
Even moving at the speed of light, some particles (e.g. Higgs)
may only travel a few mm (or less)
• Must infer what happened by observing long-lived
particles
– Need to identify the visible long-lived particles (e, p, π, μ etc)
Measure their momenta
Energy
(speed)
– Infer the presence of neutrinos and other invisible particles
Conservation laws – measure missing energy
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Particle Momentum Measurement
• Electrically charged
particles moving in a
magnetic field curve
• Radius of curvature is
related to the particle
momentum
R = p/0.3B
• Should not disturb the
passage of the particles
• Low-mass detectors
sensitive to the passage
of charged particles
• Many layers – join the
dots!
• E.g. CMS silicon tracker
Electron
In CMS
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Energy Measurement - Calorimeters
• Idea is to “stop” the particles and
measure energy deposit
• Particles stop via energy loss processes
that produce a “shower” of many
charged and neutral particles –
pair-production, bremsstrahlung etc.
• Detector can be to measure either
hadrons or electrons/photons
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The CMS Muon System
•
The Higgs decay into ZZ to 4m is preferred for Higgs masses > 160 GeV.
Coverage to || < 2.5 is required ( > 6 degrees)
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Particle interactions in detectors
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Puzzle
Find 4 straight tracks.
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Answer
Make a “cut” on the
Transverse momentum
Of the tracks:
pT>2 GeV
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Korea-CMS
Experiment Group
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Status of Korea-CMS Experiment Group
-1994 CMS Ex-Spokesperson Dr. Della Negra contacted Korean groups
< Kangnung, KNU, KU, SKKU >
-1997 KU S.K. Park research fund(190MW 3yrs) from MoST: KODEL
< KNU, KU joined CMS experiment >
-1999 KU-CERN CMS MoU(Forward RPC detector construction)
-2000 KU S.K. Park research fund (410MW 5yrs)
13 Universities(Kangwon, KNU, Konkuk, KU, Dongshin, Seonam, SNU,
Seoul Education, SKKU, Wonkwang, CNU Jeju, Chungbuk)
5 Subgroups: Single Gap Production(K.S. Shim), Assemblage(J.T. Rhee),
Network(S.B. Kim), Power Supply(Y.I. Choi), Magnet(S.K. Park)
< 11 Universities joined CMS experiment >
-2002 <KNU, Dongshin, SNU, SKKU, CNU>
withdrawed from the KU RPC Construction Project
-2003 KNU(SRC)-CERN CMS MoU(0.5MCHF DAQ PC Farm Construction)
-2006 MoST-CERN MoU (payed CMS M&O Cat. A for 2005-2007 only)
-2007 MoST Korea-CERN cooperation: organized Korea-CMS experiment group
-2008 UoS joined CMS experiment in June.
* CMS requires about 0.2MCHF/institute contribution to join CMS newly.
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[MEST] Korea-CERN Cooperation Project
□ Organization
MEST
| --- Steering Committee
KICOS
|
ALICE CMS LCG (ALICE, CMS)
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18 Prof.s applied for Korea-CMS research fund(07.3.23)
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•
•
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S.J. Hong(Gacheon-KU)
S.K. Oh(Konkuk-KNU)
J.T. Lee(Konkuk)
*K.N. Kim(KNU)
D.H. Kim(KNU)
D.C. Son(KNU)
S.K. Park(KU)
K.S. Shim(KU)
E.I. Won(KU)
B.S. Hong(KU)
K.K. Joo(SNU)
I.K. Parc(UoS-KU)
I.T. Yu(SKKU)
S.Y. Choi(SKKU)
Y.I. Choi(SKKU)
J.Y. Kim(CNNU)
E.J. Kim(CPNU-KNU)
*S.K. Choi(KSNU
Total
14.30 MWon
75.00
43.10
1,74.60
1,01.44
1,71.64
2,12.92
1,07.00
86.50
85.00
48.00
40.00
30.70
74.80
53.30
53.50
26.10
11.60
1,409.50 MWon
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Research Fund for 2007: 800MW
• SKKU: 565MW
-
Stipends
Travel expenses
Computers & Material expenses
Center operational expenses
Overhead
• CERN: 235MW
- Staying expenses:
Ph.D 4000CHF/M, Students 2500CHF/M (1CHF = 800W)
- Computers & Material expenses
- Apartment rent, car rent
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Korea-CMS group members(60 persons)
•
Team-1 Lepton(muon) group
- 교수: 김동희(경북대), 원은일(고대), 유인태, 최수용(팀장), 최영일(성대)
- 연구원: 공대정, 김지은, 김현수, 박차원, 서현관, 서준석, 주경광
- 대학원생: 고정환, 권정택, 김장호, 이종석, 정호연, 아즈말, 미안
•
Team-2 RPC group
- 교수: 박성근(팀장)(고대), 이준택(건대), 홍성종(가천의대)
- 연구원: 이경세, 장현자, 자밀
- 기술자: 정영군, 손광재, 강민호
- 대학원생: 안성환, 김태정, 임정구
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Team-3 DAQ & Analysis group
- 교수: 김귀년(팀장), 손동철(경북대), 오선근(건대), 김재률(전남대)
- 연구원: 김경숙, 김진철, 노상률, 이만우, 정진혁, 박향규, 함승우
- 대학원생: 송상현, 안상언, 서지원, 허애영, 유스포브
•
Team-4 Heavy Ion group
- 교수: 김은주(전북대), 박인규(팀장)(서울시립대), 심광숙, 홍병식(고대)
- 연구원: 김근범, 박진우, 김유상, Sood Gopika
- 대학원생: 김지현, 김현철, 문동호, 심현하, 한가람
* Anyone can join freely.
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Korea-CMS group operation
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Web site for K-CMS group
K-CMS group workshop: twice a year
(Mini-) workshops with theorists: twice or more
Annual evaluation for research activity:
(evaluate the results quantitatively)
=> M&O Cat. A. 12 selection (Authorship)
=> Research Fund
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Particle Physics Theory
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Matter and Force Particles
Leptons
Strong
Electromagnetic
Electric Charge
Tau
-1
0
Tau
Neutrino
Muon
-1
0
Muon
Neutrino
Electron
-1
Electron
Neutrino
0
Quarks
Gluons (8)
Photon
Quarks
Mesons
Baryons
Nuclei
Atoms
Light
Chemistry
Electronics
Weak
Gravitational
Electric Charge
Bottom
Strange
Down
-1/3 2/3
Top
-1/3 2/3
Charm
-1/3 2/3
Up
each quark: R,
B,
Graviton ?
Solar system
Galaxies
Black holes
G 3 colours
The particle drawings are simple artistic representations
Bosons
(W,Z)
Neutron decay
Beta radioactivity
Neutrino interactions
Burning of the sun
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The Standard Model
Me ~ 0.5 MeV
Mn ~ 0
Mt ~ 175,000 MeV!
Mg = 0
MZ ~ 100,000 MeV
Why ?
Where is Gravity?
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Unification of fundamental forces
Magnetism
QED
Electro
magnetism
Quantum
Gravity
Grand
Unification
SUSY?
Electroweak
Model
Standard
model
M axwell
Long range
Electricity
Fermi
Weak Theory
Weak Force
Short range
Nuclear Force
QCD
?
Short range
Super
Unification
Kepler Celestial
Gravity
Universal
Gravitation
Long range
Einstein, Newton
STRINGS?
Theories:
RELATIVISTIC/QUANTUM
Terrestrial
Galilei Gravity
CLASSICAL
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Origin of mass and the Higgs mechanism
Simplest theory – all particles are massless !!
A field pervades the universe
Particles interacting with this field acquire mass –
stronger the interaction larger the mass
The field is a quantum field – the quantum is the
Higgs boson
Finding the Higgs establishes the presence of the
field
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If MH < 160 GeV use H --> ZZ --> 4e or 4m
Fully active
crystals are
the best
resolution
possible
needed for
2 photon
decays of
the Higgs.
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Grand Unified Theories
•
Perhaps the strong and electroweak forces are related. In that case leptons and quarks
would make transitions and p would be unstable. The unification mass scale of a GUT
must be large enough so that the decay rate for p is < the rate limit set by experiment.
The coupling constants "run" in quantum field theories due to vacuum fluctuations. For
example, in EM the e charge is shielded by virtual g fluctuations into e+e- pairs on a
distance scale set by, le ~ 1/me. Thus a increases as M decreases, a(0) = 1/137, a(MZ) =
1/128.
Evolution of Coupling Constants in the SM
70
60
50
40
1/ a
•
30
20
a3
a2
a1
10
0
0
10
5
10
10
10
Mass(GeV)
15
10
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SUSY and Evolution of a
Evolution of Coupling Constants in SUSY
70
a3
a2
a1
60
50
1/a
40
30
20
10
0
0
10
5
10
10
10
Mass(GeV)
15
10
20
10
It is impossible to
maintain the big gap
between the Higgs mass
scale and the GUT mass
scale in the presence of
quantum radiative
corrections. One way to
restore the gap is to
postulate a relationship
between fermions and
bosons. Each SM
particle has a
supersymmetric (SUSY)
partner with spin 1/2
difference. If the mass
of the SUSY partners is
~ 1 TeV, then the GUT
unification is good - at
1016 GeV
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Unanswered questions in Particle Physics
a. Can gravity be included in a theory with the other three interactions ?
b. What is the origin of mass?  LHC
c. How many space-time dimensions do we live in ?
d. Are the particles fundamental or do they possess structure ?
e. Why is the charge on the electron equal and opposite to that on the proton?
f. Why are there three generations of quark and lepton ?
g. Why is there overwhelmingly more matter than anti-matter in the Universe ?
h. Are protons unstable ?
i. What is the nature of the dark matter that pervades our galaxy ?
j. Are there new states of matter at exceedingly high density and temperature?
k. Do the neutrinos have mass, and if so why are they so light ?
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What will we find at the LHC?
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There is a single fundamental Higgs scalar field. This appears to be incomplete
and unsatisfying.
Another layer of the “cosmic onion” is uncovered. Quarks and/or leptons are
composites of some new point like entity. This is historically plausible – atoms
 nuclei  nucleons  quarks.
There is a deep connection between Lorentz generators and spin generators.
Each known SM particle has a “super partner” differing by ½ unit in spin. An
extended set of Higgs particles exists and a whole new “SUSY” spectroscopy
exists for us to explore.
The weak interactions become strong. Resonances appear in WW and WZ
scattering as in  +   . A new force manifests itself, leading to a new
spectroscopy.
New massive vector bosons, Extra dimensions, Mini black holes,
Dark matter, Quark-gluon plasma state of the early universe
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“There are more things in heaven and earth than are dreamt of”
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Life at CERN
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14/09/07
Claire Timlin - Festival of Science
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What do I do?
What did I
do before
my PhD?
Who am I?
Introduction
Why choose a
PhD?
14/09/07
Why Experimental
Particle Physics?
Claire Timlin - Festival of Science
47
Working on the
LHC at such an
interesting time
Living near
the Alps!
Contributing to a
field of research I
care about
14/09/07
Atmosphere at
CERN
The Best
Bits!
Working in
different countries
Enjoying what
I do every day
– Well almost!
Learning
many new
skills
Working with
people who are
enthusiastic
about what they
do
Claire Timlin - Festival of Science
48
Job Security:
Can be
difficult to
obtain
permanent
positions in
the field
Pay:
Generally
not as good
as in
industry
14/09/07
The Worst
Bits!
Admin:
6 weeks
advance
notice
required for
business
trips
Claire Timlin - Festival of Science
49
14/09/07
Claire Timlin - Festival of Science
50
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A Week in the Life of an Experimental
Particle Physics Student
• Model making:
– Modelling the interactions of particles
using computer programs
– Figuring out why the results look like
they do
– Preparing to analyse data from LHC
• Meetings:
– Presenting methods and results
– Lots of lively discussion!
• Researching fields of interest
14/09/07
Claire Timlin - Festival of Science
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