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Compact Solenoid Experiment http://cmsinfo.cern.ch/

CMS Collaboration

Table of contents

The story of the Universe

Particles and forces

CERN & LHC

The Compact Muon Solenoid

CMS Collaboration. June 2003 http://cmsinfo.cern.ch/Brochures/IntroToCMS.pdf e-mail : [email protected]

The story of the Universe From the Big Bang to today's Universe

Quantum gravity era Grand unification era Electroweak era and form Nuclei are formed Atoms and light era Galaxy formation Today The size of things

01.05.03 v2 The story of the Universe 5 Quantum gravity era 10-43 s Gravity separates as a force, the other forces remain as one (Grand Unification)

?

t < 10-43 s : The Big Bang The universe is considered to have expanded from a single point with an infinitely high density (infinite temperature). Is there a meaning to the question what existed before the big bang? t ≈ 10-43 s, 1032 K (1019 GeV, 10-34 m) : Gravity “freezes” out All particle types (, leptons, gauge bosons, and undiscovered particles e.g.Higgs, sparticles, gravitons) and their anti-particles are in a thermal equilibrium (being created and annihilated at equal rate). These coexist with (radiation). Through a phase transition gravity "froze" out and became distinct in its action from the weak, electromagnetic and strong forces. The other three forces could not be distinguished from one another in their action on quarks and leptons. This is the first instance of the breaking of symmetry amongst the forces.

01.05.03 v2 The story of the Universe 6 Grand unification era 10-35 s Inflation ceases, expansion continues Grand Unification breaks. Strong and electroweak forces become distinguishable

t ≈ 10-35 s, 1027 K (1016 GeV, 10-32 m) : Inflation The rate of expansion increases exponentially for a short period. The universe doubled in size every 10-34 s. Inflation stopped at around 10-32 s. The universe increased in size by a factor of 1050. This is equivalent to an object the size of a swelling to 1019 light years across. The whole universe is estimated to have had a size of ~1023 m at the end of the period of inflation. However the presently visible universe was only 3 m in size after inflation. This solves the problems of ‘horizon’ (how is it possible for two opposing parts of the present universe to be at the same temperature when they cannot have interacted with each other before recombination) and ‘flatness’ (density of matter is close to the critical density). t ≈ 10-32 s : Strong forces freezes out Through another phase transition the strong force "freezes" out and a slight excess of matter over anti-matter develops. This excess, at a level of 1 part in a billion, is sufficient to give the presently observed predominance of matter over anti-matter. The temperature is too high for quarks to remain clumped to form neutrons or protons and so exist in the form of a plasma. The LHC can study this by colliding together high energy nuclei.

01.05.03 v2 The story of the Universe 7 Electroweak era 10-10 s

Electroweak force splits

t ≈ 10-10 s, 1015 K (100 GeV, 10-18 m) : Electromagnetic and Weak Forces separate The energy density corresponds to that at LEP. As the temperature fell the weak force "freezes" out and all four forces become distinct in their actions. The antiquarks annihilate with the quarks leaving a residual excess of matter. decay. In general unstable massive particles disappear when the temperture falls to a value at which photons from the black-body radiation do not have sufficient energy to create a particle-antiparticle pair.

01.05.03 v2 The story of the Universe 8 Protons and neutrons form 10-4 s

Quarks combine to make protons and neutrons

t ≈ 10-4 s, 1013 K (1 GeV, 10-16 m) : Protons and Neutrons form The universe has grown to the size of our solar system. As the temperature drops quark-antiquark annihilation stops and the remaining quarks combine to make protons and neutrons. t = 1 s, 1010 K (1 MeV, 10-15 m) : decouple The neutrinos become inactive (essentially do not participate further in interactions). The and annihilate and are not recreated. An excess of electrons is left. The -proton ratio shifts from 50:50 to 25:75.

01.05.03 v2 The story of the Universe 9 Nuclei are formed 100 s

Protons and neutrons combine to form helium nuclei

t = 3 minutes, 109 K (0.1 MeV, 10-12 m) : Nuclei are formed The temperature is low enough to allow nuclei to be formed. Conditions are similar to those that exist in stars today or in thermonuclear bombs. Heavier nuclei such as deuterium, helium and lithium soak up the neutrons that are present. Any remaining neutrons decay with a time constant of ~ 1000 seconds. The neutron-proton ratio is now 13:87. The bulk constitution of the universe is now in place consisting essentially of protons (75%) and helium nuclei. The temperature is still too high to form any atoms and electrons form a gas of free particles.

01.05.03 v2 The story of the Universe 10 Atoms and light era 300000 years

The Universe becomes transparent and fills with light

t = 300 000 years, 6000 K (0.5 eV, 10-10 m) : Atoms are created Electrons begin to stick to nuclei. Atoms of hydrogen, helium and lithium are created. Radiation is no longer energetic enough to break atoms. The universe becomes transparent. Matter density dominates. Astronomy can study the evolution of the Universe back to this time.

01.05.03 v2 The story of the Universe 11 Galaxy formation 1000 million years

Galaxies begin to form

t = 109 years, 18 K : Galaxy Formation Local mass density fluctuations act as seeds for stellar and galaxy formation. The exact mechanism is still not understood. Nucleosynthesis, synthesis of heavier nuclei such as carbon up to iron, starts occurring in the thermonuclear reactors that are stars. Even heavier elements are synthesized and dispersed in the brief moment during which stellar collapse and supernovae explosions occur.

01.05.03 v2 The story of the Universe 12 Today 15000 million years

Man begins to wonder where it all came from

t = 15 x 109 years, 3 K : Humans The present day. Chemical processes have linked atoms to form molecules. From the dust of stars and through coded messages (DNA) humans emerge to observe the universe around them.

01.05.03 v2 The story of the Universe 13 The size of things Big Bang Instruments 10-34 Observables 10-30 10-26 -22 Acceleratorsat 10 SUSY particle? LHC -18 Higgs? LEP 10 (range of Z/W weak force) -14 Proton (range of 10 Nuclei nuclear force) (Particle beams) -10 Atom 10 Microscope 10-6 Virus Microscope Cell

1m

106 Earth radius 1010 Earth to Sun Telescope 1014 1018 1022 Galaxies Radio 26 Radius of Telescope 10 observable Universe

Universe

01.05.03 v2 Particles and forces 14 Particle Physics

Aim to answer the two following questions

- What are the elementary constituents of matter?

- What are the fundamental forces that control their behavior at the most basic level?

01.05.03 v2 The story of the Universe 15

Particles and forces

Particles Forces Interactions: coupling of forces to matter Short history and new frontiers Unification of forces Summary

01.05.03 v2 Particles and forces 17 Particles

Leptons Electric Electric Charge Charge Tau -1 0

Muon Muon -1 Neutrino 0

Electron Electron -1 Neutrino 0

Quarks Electric Electric Charge Charge Bottom -1/3 Top 2/3

Strange -1/3 Charm 2/3

Down -1/3 Up 2/3

each quark: R, B, G 3 colors The particle drawings are simple artistic representations

01.05.03 v2 Particles and forces 18 Forces

Strong Electromagnetic

Gluons (8)

Quarks

Atoms Light Mesons Chemistry Baryons Nuclei Electronics

Gravitational Weak

Graviton ? Bosons (W,Z)

Solar system Neutron decay Galaxies Beta radioactivity Black holes Neutrino interactions Burning of the sun

The particle drawings are simple artistic representations

01.05.03 v2 Particles and forces 19 Interactions: coupling of forces to matter

Electroweak Electromagnetic Weak Charged γ Neutral + q - + + e u e e e

Zo - W ν - e- e q d e e

+ + + e e - ν e+ e e e

γ W Zo

ude- e- e- e-

Range ∞, relative strength ≤ 10-2 Range ~10-18 m, relative strength 10-14

Strong q g q'

q q'

g g qqg g g g

q' q' g g g g

Range ~ 10-15 m, relative strength = 1

01.05.03 v2 Particles and forces 20 Short history and new frontiers

λ = h / p T ≈ t -1/2 1900.... 10-10 m ≤ 10 eV >300000 Y Quantum Mechanics Atomic Physics

γ + γ 1940-50 e Quantum Electro Dynamics e- 1950-65 10-15 m MeV - GeV ≈ 3 min Nuclei, Symmetries Field theories 1965-75 10-16 m >> GeV ≈ 10-6 sec Quarks Gauge theories ueZ + SPS, pp 1970-83 10-18 m ≈ 100 GeV ≈ 10-10 sec ElectroWeak Unification, u e- QCD LEP 1990 νe νµ ντ 6 Leptons e µ τ 3 families

u c t 1994 6 Quarks d s b Top quark 3 "Colors" each quark R G B

LHC 2005 Origin of masses 10-19 m ≈ 103 GeV ≈ 10-12 sec Higgs ? ? The next step...

Underground Labs Proton Decay ? 10-32 m≈ 1016 GeV ≈ 10-32 sec GRAND Unified Theories ? The Origin of the 10-35 m≈ 1019 GeV ≈ 10-43 sec ?? Universe (Planck scale) Quantum Gravity? Superstrings ?

01.05.03 v2 Particles and forces 21 Unification of forces

Terrestrial mechanics

Universal Gravitation Inertial vs. Gravitational mass Celestial mechanics (I. Newton, 1687 )

+ − Electricity

Electromagnetism Electromagnetic waves (photon) N S Magnetism (J.C. Maxwell, 1860 )

γ γ Electromagnetism

ν e p Electroweak Intermediate bosons W, Z n Weak force e- (1970-83 )

Probing shorter distances reveals ? deeper regularities UNIFIED DESCRIPTIONS

01.05.03 v2 Particles and forces 22 Summary

10-43 sec 10-32 sec 10-10 sec 10-4 sec 100 sec 300000 years

10-35 m 10-32 m 10-18 m 10-16 m 10-15 m 10-10 m 1019 GeV 1016 GeV 102 GeV 1 GeV 1 Mev 10 eV Magnetism

QED Electro Long range Magnetism Electroweak Maxwell Electricity Model Fermi Weak Theory Weak Force Grand Standard Short range Unification model

Quantum SUSY ? Gravity QCD Nuclear Force ? Short range Super Kepler Celestial Unification Universal Gravity Long range Gravitation Einstein, Newton Terrestrial Galilei Gravity

Theories: STRINGS? RELATIVISTIC/QUANTUM CLASSICAL

01.05.03 v2 Particles and forces 23

CERN & LHC

CERN: The Laboratory The Large Collider (LHC) Collisions at LHC Detectors at LHC

01.05.03 v2 CERN & LHC 25 CERN: The Laboratory

• International organization established in 1954

• 19 member states + observers

• Today about half of the world's high-energy physics experiments are performed at CERN

• Dedicated to basic research on

elementary constituents of matter and their fundamental interactions

If you want to know more about CERN, find out through the Laboratory's invention the World-Wide Web: http://www.cern.ch/

01.05.03 v2 CERN & LHC 26 The (LHC)

ATLAS ALICE PS SPS

From LEP to LHC

Superconducting magnets

LHC-B

CMS Compact Muon Solenoid

Beams  Energy   Luminosity LEP e+ e-  200 GeV  1032 cm-2s-1 p  p 14 TeV  1034 LHC Pb Pb 1312 TeV  1027

01.05.03 v2 CERN & LHC 27 Collisions at LHC

Selection of 1 in 10,000,000,000,000

01.05.03 v2 CERN & LHC 28 Detectors at LHC

Light materials Heavy materials Central detector Hermetic calorimetry • Missing Et measurements Muon detector • Tracking, pT, MIP • Em. shower position • µ identification • Topology • Vertex

n e γγ µ p

νν

Materials with high number of protons + Active material

Electromagnetic and Hadron calorimeters • Particle identification γ (e, Jets, Missing ET) • Energy measurement Heavy materials (Iron or Copper + Active material)

Each layer identifies and enables the measurement of the or energy of the particles produced in a collision

01.05.03 v2 CERN & LHC 29

The Compact Muon Solenoid

CMS experiment CMS layout and detectors CMS trigger and data acquisition CMS physics : Higgs CMS physics : CP violation CMS physics : Supersymmetry

01.05.03 v2 The Compact Muon Solenoid 31 CMS experiment

CMS is a general purpose proton-proton detector designed to run at the highest luminosity at the LHC. It is also well adapted for studies at the initially lower luminosities. The main design goals of CMS are: 1) a highly performant muon system 2) the best possible electromagnetic calorimeter 3) a high quality central tracking 4) a hermetic hadron calorimeter

CMS detector longitudinal view

01.05.03 v2 The Compact Muon Solenoid 32 CMS layout and detectors

SUPERCONDUCTING CALORIMETERS ECAL Scintillating PbWO4 COIL Crystals HCAL Plastic brass sandwich

IRON YOKE

TRACKER Silicon Microstrips Pixels

MUON BARREL µ

4 3 2 1 wires Drift Tube Resistive Plate Chambers (DT) Chambers (RPC) strips Total weight : 12,500 t Overall diameter : 15 m MUON ENDCAPS Overall length : 21.6 m Cathode Strip Chambers (CSC) Magnetic field : 4 Resistive Plate Chambers (RPC)

01.05.03 v2 The Compact Muon Solenoid 33 CMS trigger and data acquisition

COMMUNICATION PROCESSING 16 Million channels 40 MHz 3 Gigacell buffers COLLISION RATE

Energy Tracks

100 kHz 1 Megabyte EVENT DATA LEVEL-1 TRIGGER

1 Terabit/s 200 Gigabyte BUFFERS (50000 DATA CHANNELS) 500 Readout memories

EVENT BUILDER. A large switching network (512+512 ports) with a total throughput of approximately 500 Gbit/s forms the interconnection between the sources (Readout Dual Port Memory) and the 500 Gigabit/s SWITCH NETWORK destinations (switch to Farm Interface). The Event Manager collects the status and request of event filters and distributes event building commands (read/clear) to RDPMs 5 TeraFLOP 100 Hz EVENT FILTER. It consists of a set FILTERED EVENT of high performance commercial processors organized into many farms convenient for on-line and off-line applications. The farm architecture is such that a single CPU processes one event Gigabit/s Petabyte ARCHIVE SERVICE LAN

Tera : 1012; Peta 1015; LAN : Local Area Network

01.05.03 v2 The Compact Muon Solenoid 34 CMS physics : Higgs

The (SM) of Particle Physics has unified the electromagnetic interaction (carrier: γ) and the weak interaction (carriers: W+, W-, Z0). Yet these four bosons are very different: the γ is massless whereas the W± and Z0 are quite massive (80 and 90 GeV respectively). In the framework of the SM particles acquire mass through their interaction with the Higgs field. This implies the existence of a new particle: the H0. The theory only provides a general upper mass limit of about 1 TeV, but it does predict its production rate and decay modes for each possible mass. CMS has been optimized to discover the Higgs up to a mass of 1 TeV. Examples of decay modes are:

Higgs to 2 photons (MH < 140 GeV)

Higgs to 4 leptons (140 < MH< 700 GeV)

Higgs to 2 leptons+2 jets (MH > 500 GeV)

01.05.03 v2 The Compact Muon Solenoid 35 Higgs to 2 photons (MH < 140 GeV)

H0 → γγ is the most promising channel

γ if MH is in the range 80 – 140 GeV.

The high performance PbWO4 crystal p H p electromagnetic calorimeter in CMS has been optimized for this search. The γγ mass resolution at Mγγ ~ 100 γ GeV is better than 1%, resulting in a γ S/B of ≈1/20

8000

–1 H → γγ

7000

6000 Higgs signal

5000

Events/500 MeV for 100 fb 4000

110 120 130 140 M = 100 GeV Higgs Mγγ (GeV)

01.05.03 v2 The Compact Muon Solenoid 36 Higgs to 4 leptons (140 < MH< 700 GeV)

+ In the MH range 130 - 700 GeV the most µ promising channel is H0 → ZZ*→ 2,+ 2,– or µ- H0 → ZZ → 2,+ 2,– . The detection relies Z on the excellent performance of the muon ppH chambers, the tracker and the electromagnetic calorimeter.

For MH ≤ 170 GeV a mass resolution of ~1 GeV should be achieved with the + Z µ combination of the 4 Tesla magnetic field µ- and the high resolution of the crystal calorimeter

→ → ± 80 H ZZ* 4 60 Events / 2 GeV 20 40

120 140 160 180 M = 150 GeV ± Higgs M4 (GeV)

01.05.03 v2 The Compact Muon Solenoid 37 Higgs to 2 leptons+2 jets (MH > 500 GeV)

For the highest M , in the range jet H jet 0.5 - 1 TeV, the promising channels for one year at high luminosity are H0 → ZZ → ,+ ,– νν, Z H0 → ZZ → ,+ ,– jj and p H p H0 → W+ W- → ,± ν jj . Detection relies on leptons, jets and missing transverse energy (E miss), Z t e+ for which the hadronic calorimeter (HCAL) performance is very e- important

-1 → → pb H ZZ jj 5

5 Signal Bkgd 4 yyyyyyyyyy

3

2

1

yyyyyyyyyy Events / 200GeV for 10 200 600 1000 1400 1800

MHiggs = 800 GeV MIIjj (GeV)

yyyyyy

01.05.03 v2 The Compact Muon Solenoid 38 CMS physics : CP violation

The strength of the four known forces (electromagnetic, weak, strong and gravity) does not depend on whether the particles that experience them are made of matter or antimatter. Yet, the universe we live in is completely dominated by matter. How did the universe evolve into this very asymmetric state when the underlying forces do not know the difference between matter and antimatter? A clue into this question may be provided by the phenomenon of Charge-Parity (CP) violation, discovered over three decades ago in decays of neutral (K0); these are mesons containing a strange (s) quark.

CP violation implies that there is a small difference in the decay rates of K0 and K0 mesons. One possible explanation is that there exists yet another, undiscovered, force in nature, that is not matter-antimatter symmetric. Another, more popular explanation is that the weak interaction, through which kaons decay, can actually distinguish between matter and antimatter particles. If this is true, one should be able to observe a large asymmetry in the decay rates of matter vs antimatter mesons that are made of quarks heavier than the s. The best candidate is the b quark which forms B mesons.

B physics

01.05.03 v2 The Compact Muon Solenoid 39 B physics

0 0 0 — µ+ The decay B or B → J/ψ K µ + S  presents a very clean experimental 0 signature. The particle content (B Z B0 or B0 meson) that gave the decay b — can be determined from a muon p p from the second b-flavored hadron in the event. An asymmetry in the b two rates (B0 vs B0) would signal CP violation. This would be the first time that CP violation is observed µ— jet outside the neutral system

µtag o pp→bb → + B d + X

o J/ψ K s

1500 2000 µ+µ–π–π+ 1000 Events / 10 MeV 500

0 4.8 5.0 5.2 5.4 5.6 Mµ+µ–π–π+ (GeV)

01.05.03 v2 The Compact Muon Solenoid 40 CMS physics : Supersymmetry

Supersymmetry (SUSY) postulates a relationship between matter particles (spin-1/2 or "fermions") and force carriers (integer spin or "bosons") which is not present in the Standard Model (SM). In SUSY, each fermion has a "superpartner" of spin-0 while each boson has a spin-1/2 superpartner. The Higgs sector is also extended to at least five Higgs bosons in the Minimal Supersymmetric Standard Model (MSSM). To this day, no superpartners have been observed: SUSY must be a broken symmetry, i.e. the superpartners (sparticles) must have masses different than those of their partner particles. Despite the doubling of the spectrum of particles, SUSY has many merits: it is elegant; assuming the existence of superpartners with TeV-scale masses, the Strong, Weak and Electromagnetic force strengths become equal at the same energy of ~ 1016 GeV (the "GUT scale"); it also provides a natural explanation of why the Higgs mass can be low (< 1 TeV). In SUSY theories, there is even room for explaining the in the Universe as "neutralinos" (the lightest SUSY particles LSP). If SUSY is a true symmetry of Nature and it is realized at the TeV scale, it will almost certainly be discovered in CMS

SUSY Higgs bosons SUSY Higgs: discovery ranges Sparticles Sparticles: discovery ranges

01.05.03 v2 The Compact Muon Solenoid 41 SUSY Higgs bosons

+ ν In the MSSM there are 5 Higgs e e ν bosons: h0, H0, A0 and H± decaying τ τ+ through a variety of decay modes to γ ± µ± τ± p , e , , and jets in final states. H p Below left: an example of a SUSY Higgs decay to τ τ in CMS. On the − π− τ right is the reconstructed ττ mass spectrum π− ν π+ τ

0 0 0 → τ+τ− → µ τ miss A , H , h e/ + jet + Et in bbHSUSY final states

4 -1 β 140 3 * 10 pb mA = 300 GeV, tan = 40 with b - tagging 120 e / 20 GeV

1 100 - Signal pb

4 80

60

40 τ

jet Events for 3x10 20 Total background

0 100 200 300 400 500 → ττ → τ m ττ (GeV) H e + jet("3-prong")

01.05.03 v2 The Compact Muon Solenoid 42 SUSY Higgs: discovery ranges

800 Example of the domain of β µ A0 = 0, tan = 30, > 0 700 parameter space of mSUGRA-MSSM where the 600 TH h(120) h0 can be discovered

Mbb via its decay in bb 500 100 fb-1

400 (GeV) 10 fb-1 1/2 m 300 h(116)

200 Higgs bosons in MSSM S / B > 5 100 5 σ significance contours 50 EX m = 1 TeV mtop = 175 GeV, SUSY ± 5 -1 0 200 400 600 800 1000 1200 1400 H → τν, 104 pb-1 10 pb m0 (GeV) β →µµ 20 A,H,h tan ± A,H,h → ττ → + h± + X 10 3.104 pb-1 h→ γγ inclusive

5 The search for the various LEP II MSSM Higgs bosons in s= 192 GeV 2 different decay modes allows the exploration of most of the 1 β 0 100 200 300 400 500 parameter region (tan ,mA) mA (GeV)

01.05.03 v2 The Compact Muon Solenoid 43 Sparticles

- ν e e ~χ 0 Production of sparticles may reveal 1 q itself though some spectacular χ - 1 kinematical spectra, with a + – q~ q pronounced "edge" in the , , mass 0 + – o spectrum reflecting χ → , , χ ~ 2 1 ppg production and decay. An example of such a spectrum in ~ + – miss ± q + µ inclusive , , + Et and of a 3 , − production event are shown below q χ~ 0 µ 2 ~χ 0 1

Inclusive e+e–+ Emiss final states t

250 mSUGRA parameters

m0 = 200 GeV, m1/2 = 160 GeV, Jet2 β µ tan = 2, A0 = 0, <0 Jet1 200 miss E t > 100 GeV p 1,2 > 15 GeV 150 t 3 -1 Lint = 10 pb e- SUSY + SM 100 Events / 2GeV ~χ0 1 µ- 50 µ+ ~χ0 SM 1 - 050100 150 200 250 SUSY event with M ( + -), GeV 3 leptons + 2 Jets signature

01.05.03 v2 The Compact Muon Solenoid 44 Sparticles: discovery ranges

Domains of mSUGRA parameter space (m0,m1/2) where various sparticles can be identified Gluinos and squarks can be β µ 5 -1 1000 tan = 2, A0 = 0, < 0 10 pb searched for in various ~ miss q (2000) channels with leptons + Et + jets and discovered for ~ 800 g (2000) masses up to ~ 2.2 TeV. Sleptons can be discovered ~ ~ g,q → n + X for masses up to ~ 350 GeV.

, GeV 600 The region of parameter 1/2 Ω 2

m space 0.15 < h < 0.4 — Ω h2= 0.4 where LSP would be the ~ Cold Dark Matter particle — 400 is contained well within the L

(400) explorable region

200 Ω h2= 0.15

0 400 800 1200 1600 2000 m0 GeV

Sparticles cannot escape discovery at the LHC

01.05.03 v2 The Compact Muon Solenoid 45 CMS

In total CMS will have 15,000,000 individual detector channels, all of which will be controlled by powerful computers. These will synchronize the detector with the LHC accelerator, making sure that CMS is ready to record any interesting collisions. At the LHC, bunches of protons will pass through each other 40 million times a second, and with each bunch crossing, 20 protons-proton collisions will occur on average, making 800 million collisions per second. Not all of these will produce interesting results. Most of the time, protons will just graze past each other. Head-on collisions will be quite rare, and the processes which produce new particles rarer still. The Higgs boson, for example, is expected to appear in just one of every 1013 (10,000,000,000,000) collisions. That means that even with 800 million collisions a second, a Higgs boson would only appear about once every day. Needles in haystacks seem like child’s play in comparison.

01.05.03 v2 The Compact Muon Solenoid 46

Slovak Republic • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • Tampere Univ.ofTech., Univ. ofOulu,Oulu Dpt. Physics of Institute Helsinki Tallinn Biophys., and Phys. Chemical Inst. of Univ. ofCyprus,Nicosia Split, Split Univ. of Tech. Univ. Split, Split of Univ. forScience&Tech.ofChina,Hefei,Anhui Peking Univ.,Beijing Inst. ofHighEnergyPhysics,Beijing Sofia Sofia, Univ. of Inst. forNucl.Res.andEnergy,Sofia Univ. deMons-Hainaut,Mons Univ. Catholique de Louvain, Louvain-la-Neuve Vrije UniversiteitBrussel,Brussels Univ. LibredeBruxelles,Brussels Univ. InstellingAntwerpen,Wilrijk Byelorussian StateUniv.,Minsk Res. Inst.ofAppliedPhysicalProbl.,Minsk National CentreofPart.andHEP,Minsk Institute ofNuclearProblems,Minsk HEPHY, Wien Yerevan Inst., Yerevan Physics IRES, IN2P3-CNRS-ULP,UHA,LEPSI,Strasbourg Gif-sur-Yvette DSM/DAPNIA, CEA/Saclay, Palaiseau IN2P3-CNRS, Polytech., LPNHE, Ecole IPN, IN2P3-CNRS,Univ.LyonI,Villeurbanne Annecy-le-Vieux LAPP, IN2P3-CNRS,

Inst. ofPhysicsAcademyScience,Tbilisi High EnergyPhys.Inst.,TbilisiStateUniv., Inst. f Inst. RWTH, III. Physik. Inst. B, Aachen RWTH, III. Physik. Inst. A, Aachen RWTH, I. Physik. Inst., Aachen New-Zealand of Phys., Univ. Helsinki of Helsinki,

GERMANY GEORGIA FRANCE FINLAND ESTONIA CYPRUS CROATIA CHINA, PR BULGARIA BELGIUM BELARUS AUSTRIA ARMENIA ür Exp. Kernphysik, Karlsruhe Kernphysik, Exp. ür Uzbekistan Pakistan Armenia Georgia Ukraine Belarus Turkey Serbia

, Helsinki CERN LHC Russia Korea Ireland USA Iran India Estonia Austria CMS collaboration • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • Ghulam IshaqKhanInstitute,Swabi Quaid-I-Azam Institute forStudiesinTheoreticalPhy.andMath.,Teheran Wonkwang University, Iri Wonkwang University, Seoul NationalUniv.ofEducation, Seonam University,Namwon Gyeongsang NationalUniversity,Jinju Seoul NationalUniversity, Kyungpook NationalUniversity,Taegu Korea University, Kon-Kuk University,Seoul Kangwon NationalUniversity,Chunchon Kangnung NationalUniversity, Dongshin University,Naju Choongbuk NationalUniversity,Chongju Chonnam NationalUniversity,Kwangju Cheju National University, Cheju Univ. di Univ. di Univ. di Roma I e Sez. dell' Sez. e Roma INFN, I Roma Univ. di Pisa dell' INFN, Sez. e Pisa Univ. di Univ. e di Perugia Sez. dell' INFN, Perugia Pavia INFN, dell' Sez. e Pavia Univ. di Padova dell' INFN, Sez. e Padova Univ. di Firenze dell' Sez. INFN, e Firenze Univ. di Catania INFN, dell' Sez. e Catania Univ. di dell' Sez. Bologna e INFN, Bologna Univ. di Bari dell' INFN, Sez. e Bari Univ. di TIFR -HECR,Mumbai TIFR -EHEP,Mumbai Univ. ofDelhiSouthCampus,New Bhabha AtomicRes.Centre,Mumbai Panjab Univ., Chandigarh Institute ofNuclearResearchATOMKI,Debrecen Kossuth LajosUniv.,Debrecen Inst. KFKI Res. Part. Nucl. & Phys., Budapest for Univ. ofIoánnina,Ioánnina Attiki Nucl. Phys. "Demokritos", Inst. of Univ. ofAthens,Athens Cyprus PAKISTAN KOREA ITALY IRAN INDIA HUNGARY GREECE China (Taiwan) Croatia Torino eSez.dell'INFN, Genova eSez.dell'INFN, UK China, PR Univ., Islamabad Brazil Seoul (152 Institutionswithabout1900scientists) Belgium CERN France Italy Spain Portugal Poland Bulgaria Finland Germany Hungary Greece • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •

hro tt nv, Kharkov Univ., Kharkov State Kharkov Phys. Kharkov Inst. Tech., and of Nat.Acad.ofScience,Kharkov Crystalsof Single of Inst. Ankara Univ., Technical Middle East Cukurova Univ.,Adana Zurich Univ. Zürich, Inst. fürTeilchenphysik,ETH,Zurich Villigen Inst., Paul Scherrer CERN, Geneva Univ. Basel, Basel IFCA, CSIC-Univ.deCantabria,Santander Univ. deOviedo,Oviedo Univ. AutónomadeMadrid,Madrid CIEMAT, Madrid of Bratislava Slovak University Technology, Petersburg Nucl.Phys.Inst.,Gatchina(StPetersburg) Inst. forHighEnergyPhys.,Protvino Moscow StateUniv., P.N. LebedevPhys.Inst.,Moscow Inst. forTheoreticalandExp.Phys.,Moscow Inst. forNucl.Res.,Moscow JINR, Dubna LIP, Lisboa Nucl. Warsaw Soltan Inst. Studies, for Exp. Inst. of Phys., Warsaw RAL, Didcot Imperial College,Univ.ofLondon,London Brunel Univ.,Uxbridge Bristol Bristol, Univ. of Bogazici University, Dep. of Physi of Dep. University, Bogazici National TaiwanUniversity,Taipei National CentralUniversity,Chung-Li,Taipei UNITED KINGDOM UKRAINE TURKEY TAIPEI SWITZERLAND SPAIN SLOVAK REPUBLIC RUSSIA PORTUGAL POLAND

cs, Instambul (Bebek) Instambul cs, • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • Univ. ofWisconsin,Madison Virginia Polytech. Inst. and State Univ., Blacksburg Jolla La Diego, California San Univ. of UCLA, LosAngeles Davis Davis, at California Univ. of Richardson Dallas, at Univ. of Texas Texas TechUniv.,Lubbock Rutgers, theStateUniv.ofNewJersey,Piscataway Univ. ofRochester,Rochester Univ. of California, Riverside Rice Univ.,Houston Purdue Univ. , West Lafayette Princeton Univ., The OhioStateUniv.,Columbus Univ. ofNotreDame,Dame Northwestern Univ.,Evanston Boston Northeastern Univ., Univ. ofNebraska-Lincoln,Lincoln Massachusetts Inst.ofTech.,Cambridge Univ. ofMississippi,Oxford Univ. ofMinnesota,Minneapolis Univ. of Park Maryland, College Los AlamosNat.Lab., LLNL, Livermore Johns HopkinsUniv.,Baltimore City Iowa Iowa, of The Univ. Gainesville Univ. of Florida, Univ. Tallahassee - Florida State SCRI, Univ. Florida State - HEPG, Tallahassee Batavia Accelerator Lab., Fermi National Fairfield Univ., Fairfield Chicago Chicago, at Illinois Univ. of Carnegie MellonUniv.,Pittsburgh California Inst. of Tech., Pasadena Boston Univ., Ames Univ., Iowa State Univ. ofAlabama,Tuscaloosa Tashkent Inst. ofNucl.Phys.theUzbekistanAcad.Sciences, USA UZBEKISTAN

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