Large Hadron Collider&

ATLAS, CMS Experiments

Bing ZhouBing Zhou

The University of MichiganThe University of Michigan

CCAST Worshop @Tsinghua UniversityCCAST Worshop @Tsinghua University

Nov. 6-11, 2006 Nov. 6-11, 2006

Outline

1)1) Introduction – from SSC to LHCIntroduction – from SSC to LHC

2)2) LHC Status and Start up PlanLHC Status and Start up Plan

3) Status of the LHC detectors: ATLAS & CMS3) Status of the LHC detectors: ATLAS & CMS

-- detector design and construction-- detector design and construction

-- installation and commissioning-- installation and commissioning

4) Physics Potential of the LHC Experiments4) Physics Potential of the LHC Experiments

-- Physics study tools-- Physics study tools

-- Discovery potentials-- Discovery potentials

5) Grid Computing for LHC experiments 5) Grid Computing for LHC experiments

3

Introduction

Why need TeV energy ?

•Traditionally, particle physics have focused on the inner space frontier, pursuing the questions of the construction of matter and the fundamental forces at the smallest scale accessible. ~ h/p smaller distance ~ higher energy• Today, we also pressing the questions from universe – dark matter and dark energy. The understanding of the micro- world and our tools are invaluable in investigating universe at large, and the cosmic phenomena effect microphysics high energy physics.

4

What is Universe Made of ?

Dark matter particlesmass and interactions

Standard Model Higgs Boson etc.Intriguingly, dark matter points to the

same place where the standard model starts to break

down …

5

The Energy Scale

1 eV

1 GeV100 GeV

1018 GeV

LHCTevatron

QCD Confines

Generation of mass

Higgs?

Right-handed neutrinos?

Unification of Forces?Quantum Gravity ? • Particle Physics today explores a very

wide range of energies

• Of particular interest are the highest

energies, corresponding to the

smallest distances and most massive

elementary particles.

• The TeV scale contains the mystery

of Electroweak symmetry breaking.

• Hope a more unified force to describe

nature.Atomic process

1 MeV Nuclear process

6

LHC-Energy: 14 Trillions of Electron-Volts

• The The Large Hadron Collider (LHC)Large Hadron Collider (LHC) at CERN will at CERN will accelerate each of two counter-rotating beams of protons accelerate each of two counter-rotating beams of protons to 7 TeV per proton. to 7 TeV per proton.

7

The Universe is a Mysterious Place!The Early Universe IS high energy physics

•We only ‘understand

About 5% of matter &

Energy content of the

Universe.• Particle physics, as

the science of matter,

energy, space and time

Must help to explain the

early universe and dark

world of universe.•Dark matter & dark energy are among among the top questions in physical science today

8

The Revolution is Coming!

• The standard model makes precise and accurate predictionsThe standard model makes precise and accurate predictions

• It provides an understanding of what It provides an understanding of what protons, neutrons, atoms, stars, you protons, neutrons, atoms, stars, you

and me and me are made ofare made of

But (like capitalism!) it contains the seeds of its own destruction

But (like capitalism!) it contains the seeds of its own destruction

• Its spectacular success in describing phenomena Its spectacular success in describing phenomena at energy scales below 1 TeV is based onat energy scales below 1 TeV is based on

• At least one unobserved ingredient • the Higgs Boson

• Whose mass is unstable in quantum mechanics • requires additional new forces or particles to fix

• It is common conviction that SM is fundamentally incomplete and flawed (a It is common conviction that SM is fundamentally incomplete and flawed (a long list of fundamental questions on SM).long list of fundamental questions on SM).

• The way forward is through experiments at The way forward is through experiments at particle acceleratorsparticle accelerators

From SSC to LHC““Without new observations we cannot advance our Without new observations we cannot advance our

understanding in particle physics .”understanding in particle physics .”

““We need a Super-Conducting Super Collider to explore We need a Super-Conducting Super Collider to explore

new physics in TeV energy scale.”new physics in TeV energy scale.”

--- 1984 C. Quigg at el. wrote a review paper on TeV --- 1984 C. Quigg at el. wrote a review paper on TeV

physics, which performed many fundamental calculations physics, which performed many fundamental calculations

and defined the major parameters of the next generation and defined the major parameters of the next generation

hadron Collider (SSC):hadron Collider (SSC):

Center-of-mass energy: 40 TeV (20 TeV per beam)Center-of-mass energy: 40 TeV (20 TeV per beam)

Luminosity: 10Luminosity: 1033 33 cmcm-2-2 s s-1-1

From SSC to LHC

1987 – 1990 Design SSC detectors and form collaborations1987 – 1990 Design SSC detectors and form collaborations

---- SCD (Approved by SSC Program Advisory Committee) SCD (Approved by SSC Program Advisory Committee)

-- -- L* (S.S. C. Ting)L* (S.S. C. Ting) (Approved by PAC) (Approved by PAC)

-- EMPACT-- EMPACT

-- Taxas-- Taxas

-- -- GEMGEM (Barish & Willis) detector design in 1990 followed (Barish & Willis) detector design in 1990 followed

L* design principle : precision Gamma, Electron and Muon L* design principle : precision Gamma, Electron and Muon

1993: US Congress killed SSC project1993: US Congress killed SSC project

1992 – 1994: Design LHC detectors and form collaborations1992 – 1994: Design LHC detectors and form collaborations

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Large Hadron Collider in LEP tunnel

Initial LHC parameter in 14 years ago

Main Detector proposals

(Express of Interest)

Mar.1992•L3+1L3P (S. Ting)•EAGLE (Jenni)•ASCOT (Norton)•CMS (M. Negra, J. C. Lattin)

1994: LoI: ATLAS & CMS

ATLAS

SSC Accelerator & Detecor

R&D results LHC

12

First Beams: Fall 2007Physics Runs: from Spring 2008

TOTEM pp, general purpose; HI

pp, general purpose; HI

LHCb: B-physics

ALICE : HI

27 km Tunnel in Switzerland & France

CMS

Atlaspp, general purpose; HI

pp, general purpose; HI

The Large Hadron Collider at CERNCM = 14 GeV, Lumi = 1034 cm-2 s-1

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LHC Construction Team: CERN, US, Japan

14

Global Requirements on The Machine

• Highest energy proton collisions for ATLAS and CMSHighest energy proton collisions for ATLAS and CMS

• Nominal luminosity 1034 cm-2 s-1 in points 1 and 5

• Highest energy proton collisions for LHCbHighest energy proton collisions for LHCb

• Nominal luminosity ~ 5 1032 cm-2 s-1 in point 8

• Proton collisions @ various energies for ALICEProton collisions @ various energies for ALICE

• Nominal luminosity ~ 1030 cm-2 s-1 in point 2

• Ion collisions @ various energies for ALICEIon collisions @ various energies for ALICE

• Nominal luminosity ~ 1027 cm-2 s-1 in point 2

• ATLAS and CMS will also take data

• Proton collisions @ various energies for TOTEMProton collisions @ various energies for TOTEM

Proton luminosity

running

Dedicated

Dedicated

15

Proton luminosity running

HHSM SM -> 4 l (M -> 4 l (MHiggs Higgs = 140-155 GeV and 190-450 GeV) can be discovered with = 140-155 GeV and 190-450 GeV) can be discovered with ~ 5 fb~ 5 fb-1 -1

Some supersymmetry can be discovered at more modest luminosities ~ 1 fbSome supersymmetry can be discovered at more modest luminosities ~ 1 fb -1-1

ATLAS and CMSATLAS and CMS

• Minimize event pileup early on

• Go to 25ns as soon as possible

• Will make use of any beam for detector commissioning

LHCbLHCb• Tune IP8 to optimize luminosity (1m < * > 50m)• Go to 25ns as soon as possible (optimized for ~ 1 events/crossing)• Dipole polarity change ~ every fill (!)

ALICEALICE• Will use proton beams (intrinsic interest and reference data)• Tune IP2 to optimize luminosity (0.5m < * > 50m)• Magnet polarities change ( + - 0 ) a few times per year

(106 seconds @ <L> of 1033 cm-2 s-1 = 1 fb-1)

16

LHC High Luminosity Run

17

2808 is a lot of bunches per beam

• Filling scheme requires Filling scheme requires 12 SPS cycles per beam12 SPS cycles per beam

• Each with 2,3 or 4 batches of 72 bunches

• Crossing angle neededCrossing angle needed

• Emittance conservation with 10Emittance conservation with 101111

protons per bunch throughprotons per bunch through

• Injecting

• Ramping

• Squeezing to 0.55m

18

362MJ is a lot of beam energy to handle

19

Each Proton bunch is like a bullet!

20

21

News from the LHC machine

22

LHC Schedule as presented to CERN Council on 23 June 2006

Last magnet installed : March 2007 Machine and experiments closed : 31 August 2007

First collisions (s = 900 GeV, L~1029 cm-2 s-1) : November 2007 Commissioning run at injection energy until end 2007, then shutdown (3-4 months)

First collisions at s=14 TeV (followed by first physics run): Spring 2008

Goal : deliver integrated luminosity of few fb-1 by end 2008

The main features of the new schedule are:

- The beam pipe closure date will be end of August 2007 (instead of end of June 2007)

- After that there will still be a few weeks of controlled access to the cavern

- This is followed by an LHC commissioning run with collisions at the injection energy (450 + 450 GeV), until the end of 2007

- Then there will be a shut-down (typically 3 months) during which the remaining machine sectors will be commissioned without beam to full energy (7 TeV)

- After that the LHC will be brought into operation for the first physics run at 14 TeV, with the aim to integrate substantial luminosity by the end of 2008

23

Last magnet deliveredLast magnet delivered October 2006October 2006

Last magnet testedLast magnet tested December 2006December 2006

Last magnet installedLast magnet installed March 2007March 2007

Machine closedMachine closed August 2007August 2007

First collisionsFirst collisions November 2007November 2007

Milestones for the machine

- - Sectors 7-8 and 8-1 will be fully commissioned up to 7 TeV in 2006-2007. If weSectors 7-8 and 8-1 will be fully commissioned up to 7 TeV in 2006-2007. If we

continue to commission the other sectors up to 7 TeV, we will not get circulating beam continue to commission the other sectors up to 7 TeV, we will not get circulating beam

in 2007.in 2007.

- The other sectors will be commissioned up to the field needed for de-Gaussing.- The other sectors will be commissioned up to the field needed for de-Gaussing.

- Initial operation will be at 900 GeV (CM) with a static machine (no ramp, no- Initial operation will be at 900 GeV (CM) with a static machine (no ramp, no

squeeze) to debug machine and detectors.squeeze) to debug machine and detectors.

- Full commissioning up to 7 TeV will be done in the winter 2008 shutdown- Full commissioning up to 7 TeV will be done in the winter 2008 shutdown

LHC commissioning

(Presented by CERN to SPC and Council)

24

Sector test with beam

Aim to send beam Out of SPS TT40 Down TI8 Inject into LHC R8 Through insertion R8 Through LHCb Through IP8 Through insertion L8 Through arc 8-7 To dump at Q6 R7

25

Apr. 2005First magnets were installed

in the LHC tunnel.

Oct. 2005

July 2006Half-way point(616th) forthe 1232 dipole magnets

“The longest journey:the LHC dipoles arrive on time”

(CERN Courier, Oct. 2006)

26

Number of quenches to reach nominal fieldfor dipoles on second thermal cycle

27

CERN management’s conclusion

(Presented last week by J Engelen at theCracow Physics at LHC conference)

We now have enough information to produce a consolidated plan for

commissioning.

Three quarters of the machine has been liberated for magnet installation

and interconnect work is proceeding in 2 octants in parallel. Magnet

installation is now steady at 25/wk . Installation will finish March 2007. The

machine will be closed in August 2007.

Every effort is being made to establish colliding beams before the end of

2007 at reduced energy. The full commissioning up to 7 TeV will be done

during the 2008 winter shutdown ready for a Physics run at full energy in

spring 2008.

28

Staged commissioning plan for protonsStaged commissioning plan for protons

25ns ops IInstall Phase II and MKB

25ns ops II

75ns ops

43 bunch operation

Beam commissioning

Machine checkout

Hardware commissioning

Stage I II III

No beam Beam

IV

I.I. Pilot physics runPilot physics run First collisionsFirst collisions 43 bunches, no crossing angle, no squeeze, moderate intensities43 bunches, no crossing angle, no squeeze, moderate intensities Push performance (156 bunches, partial squeeze in 1 and 5, push Push performance (156 bunches, partial squeeze in 1 and 5, push intensity)intensity) Performance limit 10Performance limit 103232 cmcm--22 ss--11 (event pileup)(event pileup)

II.II. 75ns operation75ns operation Establish multiEstablish multi--bunch operation, moderate intensitiesbunch operation, moderate intensities Relaxed machine parameters (squeeze and crossing angle)Relaxed machine parameters (squeeze and crossing angle) Push squeeze and crossing angle Push squeeze and crossing angle Performance limit 10Performance limit 103333 cmcm--22 ss--11 (event pileup)(event pileup)

III.III. 25ns operation I25ns operation I Nominal crossing angleNominal crossing angle Push squeezePush squeeze Increase intensity to 50% nominalIncrease intensity to 50% nominal Performance limit 2 10Performance limit 2 103333 cmcm--22 ss--11

IV.IV. 25ns operation II25ns operation II Push towards nominal performancePush towards nominal performance

2008-2009

2010

up to 1-2 fb-1 end 2008, up to 10fb-1 end 2009 ?

O(100) fb-1

Note: dates and integrated luminosities are MY interpretation (F. Gianotti)

2008

29

Stage I Commissioning

• Start as simple as possibleStart as simple as possible• No squeeze

* = 18m in 1 & 5 * = 10m in 2 & 8

• Avoid parasitic beam-beam• No crossing angle• D1L to D1R ~ 116m• Minimum bunch spacing 232m, ~ 0.8μs• 43 bunches per beam convenient for the injectors, spacing 2.025μs

• Switch off all unused equipment

• Under these relatively clean, safe conditionsUnder these relatively clean, safe conditions• Injection of beam from SPS is always safe• Stored beam energy comparable to other facilities• Commission the nominal cycle• Establish reproducible operation• Commission machine protection systems• Beam measurement campaign• Make a few single beam runs at top energy• First high energy collisions• Increase performance

• Bring on crossing angleBring on crossing angle• Luminosity may well go down (remember SPS collider and LEP)• Recover as much as possible without parasitic beam-beam

30

Stage I physics run

•Start as simple as possibleStart as simple as possible

•Change 1 parameter Change 1 parameter (k(kbb N N **1 , 51 , 5)) at a time at a time

•All values forAll values for

• 7TeV

• 10m * in point 2 (luminosity looks fine)ParametersParameters Beam levelsBeam levels Rates in 1 and 5Rates in 1 and 5 Rates in 2Rates in 2

kkbb NN * 1,5* 1,5

(m)(m)

IIbeambeam

protonproton

EEbeambeam

(MJ)(MJ)

LuminosityLuminosity

(cm(cm-2-2ss-1-1))

Events/Events/

crossingcrossing

LuminosityLuminosity

(cm(cm-2-2ss-1-1))

Events/Events/

crossingcrossing

11 10101010 1818 1 101 101010 1010-2-2 10102727 << 1<< 1 1.8 101.8 102727 << 1<< 1

4343 10101010 1818 4.3 104.3 101111 0.50.5 4.2 104.2 102828 << 1<< 1 7.7 107.7 102828 << 1<< 1

4343 4 104 101010 1818 1.7 101.7 101212 22 6.8 106.8 102929 << 1<< 1 1.2 101.2 103030 0.150.15

4343 4 104 101010 22 1.7 101.7 101212 22 6.1 106.1 103030 0.760.76 1.2 101.2 103030 0.150.15

156156 4 104 101010 22 6.2 106.2 101212 77 2.2 102.2 103131 0.760.76 4.4 104.4 103030 0.150.15

156156 99 10 101010 22 1.4 101.4 101313 1616 1.1 101.1 103232 3.93.9 2.2 102.2 103131 0.770.77

FfkN

Ln

b*

2

4

fk

LCrossEventrate

b

TOT/

Protons/beam ≾ 1013

(LEP beam currents)

Stored energy/beam ≾ 10MJ(SPS fixed target beam)

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Stage II physics run FfkN

Ln

b*

2

4

ParametersParameters Beam levelsBeam levels Rates in 1 and 5Rates in 1 and 5 Rates in 2 and 8Rates in 2 and 8

kkbb NN * 1,5* 1,5

(m)(m)

IIbeambeam

protonproton

EEbeambeam

(MJ)(MJ)

LuminosityLuminosity

(cm(cm-2-2ss-1-1))

Events/Events/

crossingcrossing

LuminosityLuminosity

(cm(cm-2-2ss-1-1))

Events/Events/

crossingcrossing

936936 4 104 101010 1818 3.7 103.7 101313 4242 1.5 101.5 103131 << 1<< 1 2.6 102.6 103131 0.150.15

936936 4 104 101010 22 3.7 103.7 101313 4242 1.3 101.3 103232 0.730.73 2.6 102.6 103131 0.150.15

936936 4 104 101010 11 3.7 103.7 101313 4242 2.5 102.5 103232 1.41.4 2.6 102.6 103131 0.150.15

936936 99 10 101010 11 8.4 108.4 101313 9494 1.2 101.2 103333 77 1.3 101.3 103232 0.760.76

•Relaxed crossing angle (250 Relaxed crossing angle (250 rad)rad)•Start un-squeezedStart un-squeezed•Then go to where we were in stage IThen go to where we were in stage I•All values for All values for

• nominal emittance• 7TeV• 10m * in points 2 and 8

Protons/beam ≈ few 1013

fk

LCrossEventrate

b

TOT/

2

*21/1

zcF

Stored energy/beam ≤ 100MJ

32

Stage III physics run FfkN

Ln

b*

2

4

ParametersParameters Beam levelsBeam levels Rates in 1 and 5Rates in 1 and 5 Rates in 2 and 8Rates in 2 and 8

kkbb NN * 1,5* 1,5

(m)(m)

IIbeambeam

protonproton

EEbeambeam

(MJ)(MJ)

LuminosityLuminosity

(cm(cm-2-2ss-1-1))

Events/Events/

crossingcrossing

LuminosityLuminosity

(cm(cm-2-2ss-1-1))

Events/Events/

crossingcrossing

28082808 4 104 101010 1818 1.1 101.1 101414 126126 4.4 104.4 103131 << 1<< 1 7.9 107.9 103131 0.150.15

28082808 4 104 101010 22 1.1 101.1 101414 126126 3.8 103.8 103232 0.720.72 7.9 107.9 103131 0.150.15

28082808 55 10 101010 22 1.4 101.4 101414 157157 5.9 105.9 103232 1.11.1 1.2 101.2 103232 0.240.24

28082808 5 105 101010 11 1.4 101.4 101414 157157 1.1 101.1 103333 2.12.1 1.2 101.2 103232 0.240.24

28082808 5 105 101010 0.550.55 1.4 101.4 101414 157157 1.9 101.9 103333 3.63.6 1.2 101.2 103232 0.240.24

NominalNominal 3.2 103.2 101414 362362 10103434 1919 6.5 106.5 103232 1.21.2

fk

LCrossEventrate

b

TOT/

•Nominal crossing angle (285 Nominal crossing angle (285 rad)rad)•Start un-squeezedStart un-squeezed•Then go to where we were in stage IIThen go to where we were in stage II•All values for All values for

• nominal emittance• 7TeV• 10m * in points 2 and 8

Protons/beam ≈ 1014

2

*21/1

zcF

Stored energy/beam ≥ 100MJ

33

Breakdown of a normal year

7-8

~ 140-160 days for physics per yearNot forgetting ion and TOTEM operation

Leaves ~ 100-120 days for proton luminosity running? Efficiency for physics 50% ?

~ 1200 h or ~ 4 106 s of proton luminosity running / year

34

List of Questions on SM