Experimental High Energy Physics in the Next Centuryhep.wisc.edu/wsmith/Dept_Cent.pdf · 1999. 10....

October., 1999Wesley Smith, U. Wisconsin

Experimental High Energy Physics in the Next Century Experimental High Energy

Physics in the Next Century

Wesley H. Smith Physics Department

University of Wisconsin - Madison

UW- Madison Physics Department Centennial Celebration

October 8, 1999

S. Cittolin EP/CMD99CSC-Poland

10-10 m ≤ 10 eV >300000 Y

10-15 m MeV - GeV

10-16 m >> GeV ≈ 10-6 sec

10-18 m ≈ 100 GeV ≈ 10-10 sec

1900.... Quantum Mechanics Atomic Physics

1940-50 Quantum Electro Dynamics

1950-65 Nuclei, Hadrons Symmetries, Field theories

1965-75 Quarks. Gauge theories

1990 LEP 3 families

10-19 m ≈ 103 GeVOrigin of massesThe next step...

≈ 10-12 sec 2005 LHC Higgs ? Supersymmetry ?

1970-83 SPS ElectroWeak Unification, QCD

λ = h / p T ≈ t -1/2

≈ 3 min

10-32 m ≈ 1016 GeV ≈ 10-32 secProton Decay ? Underground Labs GRAND Unified Theories ?

10-35 m ≈ 1019 GeV(Planck scale)

≈ 10-43 sec ?? Quantum Gravity? Superstrings ?

The Origin of the Universe

1994 Tevatron Top quark

u e+Z

e-u

Short history and new frontiers

γe+

e-

γ

ud

cs

tb

eνe

µνµ ντ

τ

6 Quarks

6 Leptons

3 "Colors" each quark G BR

4


Towards the origin

6

10-33

10

107

1013

1019

1025

1031

10 -10

3min

Quarks and Leptons Hadrons Atoms

StarsGalaxy

Time after Big Bang

Tem

per

atu

re (

° K

)

LEPLHC

today

Nuclei

10-6

Extrapolation

SS S 15 BillionYears

Nucleo-synthesis

LHCions

pp

http://cmsdoc.cern.ch/pictures/publicity/overview.html

Fundamental Open Questions in Particle Physics

• Why is the Z boson massive while the related photon is massless ? What is the "origin" of mass ?

• Can we obtain experimental evidence to support the hypothesis of Grand Unification of all fundamental forces ?

• Is the "dark matter" in the universe due to supersymmetric particles : neutralinos ?

• Can we account for the matter - antimatter asymmetry in our universe?

• Are there only 3 families of quarks and leptons ?

• Do the elementary particles of today have sub-structure ?

• Does a new form of matter exist (quark-gluon plasma)? It should have existed in the early universe.

LHC and CMS can answer or shed considerable light on these fundamental questions.

?


• HIGGS : Clarify the origin of the spontaneous symmetry-breaking

mechanism in the EW sector of the Standard Model (-> Higgs,

SUSY)

• NEW FORCES (symmetries)• New particles• Super symmetries• Substructure........

The next step

p pH

µ+

µ-

µ+

µ-

Z

Z

p p

e- νe

µ+

µ−

q

q

q

qχ

1-

g~

~

χ20~

q~

χ10~

5


b quark

LHC

Accelerators

hadron

electron

SLC

Prin-Stan

ISR

SPEAR

CESR

TRISTAN

SppS

Tevatron

PEP

s quark

c quark

W, Z bosons

Higgs boson

LEPII t quark

1970 1980 1990 2000

1 GeV

10 GeV

100 GeV

1TeV

High Energy Physics Accelerators up to the Millenium

High Energy Physics Accelerators up to the Millenium

HEP facilities plotted by discovery reach in mass vs. year

Also shown are some important discoveries and the expected range for the Higgs


The Higgs at the beginning of the Millenium

The Higgs at the beginning of the Millenium

Large Electron-Positron Collider at CERN• Searches up to center of mass energy ~ 200 GeV• Show results for latest search up to 196 GeV

Tevatron II & III at Fermilab• Proton-Anti Proton Collisions at center of mass

energy of 2 TeV• CDF and D0 Detectors operating at increasing

luminosity for the first 5 years of the next millenium (at least)

The Large Hadron Collider at CERN• Proton-Proton Collisions at center of mass energy

of 14 TeV• ATLAS and CMS Detectors operating at increasing

luminosity starting in 2005

Standard Model Higgs Limit

To set limits on Higgs mass hypothesis, look at CLs:

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

90 92 94 96 98 100 102 104 106 108 110

mH(GeV/c2)

CL

s

Observed Limit

LEP 196

ObservedExpected

For all combination methods,all mH ≤ 102.6 GeV/c2, CLs ≤ 0.05.

Therefore, a limit on the Higgs mass is set:

mH > 102.6 GeV/c2 @ 95% C.L.

(with 102.3 GeV/c2 expected)

Sept. 7, 1999

LEPC meeting

LEP Higgs Working Group Status Report (page 17)

Higgs Searches up to√

s = 196 GeV

PeterMcNamara

University of Wisconsin


Tevatron Run II & III Higgs Searches

Tevatron Run II & III Higgs Searches

Predicted maximum possible limits achievable forfinding or ruling out Higgs at Tevatron Run II & Run III.


Superconducting magnets

SPSPS

CMS

The Large Hadron Collider (LHC)

LHCb

ALICE

Beams Energy Luminosity

e+ e– 200 GeV 1032 cm-2s-1

p p 14 TeV 1034

Pb Pb 1312 TeV 1027

LEP

LHC

From LEP to LHC

ATLAS

7


Selectivity: the Physics, pp Cross Section

8

σto

t

σ

σt t

(W

)ν

σz'

σH

iggs

σH

m

= 5

00 G

eV

m

= 1

00 G

eV

HH

m

= 1

75 G

eVto

p

m

= 1

TeV

1 m

b

1

b

1 nb

1 pbµ

0.1

1.0

1010

0

s

TeV

z'

σ

σ jet

E

>0.

25 T

eVtje

t

σb

b

(proton - proton)

0.00

10.

01

CE

RN

Fer

mila

b LHCS

SC

UA

1

E71

0

UA

4/5

UA

1/2

CD

F (

p p)

(p p

)

9 7 5 -13

10 10 10 1010

-310

Events / sec for = 10 cm sec 34-2-1

10

CD

F

CD

F/D

Om

top =

174

GeV

σ gg

(mg

= 5

00 G

eV)

~~

~


10

10 2

10-1

1 10 102

103

104

105

106

107

108

109

elastic

total⇓

pp

Cro

ss s

ecti

on (

mb)

Center of mass energy (GeV)1.9 2 10 102 103 104

pp Cross section & Min Bias

σinel (pp) ≈ 70 mb• L = 1034 cm-2 s-1=107 mb-1 Hz• σinel (pp) ≈ 70 mb

• ∆t = 25 ns = 25 x 10-9 Hz-1

• Not all bunches full (2835/3564)

→ Event Rate = 7 x 108 Hz

→ Events/25ns =7 x 2.5 = 17.5

Operating conditions (summary):1) A "good" event containing a Higgs decay +2) ≈ 20 extra "bad" (minimum bias) interactions

→ Events/crossing = 23

9


All charged tracks with pt > 2 GeV

Reconstructed tracks with pt > 25 GeV

Higgs decay in 4 µ (+30 minimum bias events)

10


Detectors at LHC

Central detector• Tracking, p

T, MIP

• Em. shower position• Topology

• Vertex

Electromagnetic and Hadron calorimeters• Particle identification (e, γ Jets, Missing E

T)

• Energy measurement

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

µ

n

p

γ

Heavy materials

ν

Heavy materials(Iron or Copper + Active material)

e

Materials with high number of protons + Active material

12

Light materials

Muon detector• µ identification

Hermetic calorimetry• Missing Et measurements


MUON BARREL

CALORIMETERS

Micro Strip Gas Chambers (MSGC)Silicon MicrostripsPixels

ECAL Scintillating PbWO4

Crystals

Cathode Strip Chambers (CSC)Resistive Plate Chambers (RPC)

Drift Tube Chambers (DT)

Resistive Plate Chambers (RPC)

strips

wire

s

µ4

32

1

SUPERCONDUCTING COIL

IRON YOKE

TRACKERs

MUON ENDCAPS

CMS layout and detectors

Total weight : 12,500 tOverall diameter : 15 mOverall length : 21.6 mMagnetic field : 4 Tesla

HCAL Plastic scintillator copper sandwich

16


ll

jet

Particle

jet

Proton-Proton 2835 bunch/beam Protons/bunch 1011

Beam energy 7 TeV (7x1012 eV)Luminosity 1034 cm-2 s-1

Crossing rate 40 MHz

Collisions ≈ 107 - 109 Hz

Parton(quark, gluon)

Proton

Selection of 1 in

10,000,000,000,000

Collisions at LHC

Bunch

SUSY.....

Higgs

Zo

Zo

Higgs

e+

e+

e-

e-

17


10-2

100

102

104

106

108

10-8 10-6 10-4 10-2 100

25 ns ≈ µs ms sec

QED

W,Z

Top

Z*

Higgs

Available processing time

LEVEL-1 Trigger 40 MHz Hardwired processors (ASIC, FPGA) MASSIVE PARALLEL Pipelined Logic Systems

HIGH LEVEL TRIGGERS 100 kHzStandard processor FARMs

10-4

Rate (Hz)

≈ 1 µs

≈ 0.01 - 1 sec

Event selection and computing stages

36


Next Linear ColliderNext Linear Collider

Electron-Positron Collider optimized for physics at 1.0 TeV

• Compatible with 500 GeV to 1.5 TeV

Evolution:• Intially 500 GeV, 5x1033 cm-2s-1

• Proven RF technology• Linac sized for 1 TeV• Sources & Final Focus for 1.5 TeV

• Adiabatically increase to 1 TeV, > 1034 cm-2s-1

• Final Upgrade to 1.5 TeV, > 1034 cm-2s-1

• Requires additional RF development


NLC PhysicsNLC Physics

New particles• Clean environment

Elucidating new phyiscs• Precision Instrument - energy & polarization

Explore electroweak symmetry breaking• Standard Model provides precise predictions• Deviations indicate new physics (new Z0, compositeness,

contact interactions)

Study Higgs:• Mass (∆p/p ~ 300 MeV), couplings, BR

Study Supersymmetry• Determine spectrum, masses, couplings, cross sections,

mixings among particles


NLC StatusNLC Status

Experience with accelerator & physics at Stanford Linear Collider since 1991.

Components demonstrated:• Damping Ring:ATF at KEK (Japan) is operating• X-Band Accelerator - NLCTA at SLAC operating• Final Focus Test beam demonstrated required

demagnification

Systematic Feasibility established with detailed design studies

Ready to move to conceptual design phase• Close collaboration between international partners• Starting detector R&D

Construction start in middle of next decade?


Very Large Hadron ColliderVery Large Hadron Collider

VLHC Goals:• Design an affordable machine• Baseline Specifications:

• 100 - 200 TeV,• 100+ km tunnel• L=1034s-1cm-2

• Choose a magnet and thus tunnel length

• Determine economic method of digging 100+ km tunnel

G. William Foster June 99

VLHC at Fermilab


2-in-1 Warm-Iron“Double-C” Magnet

Flux Return

20 cm.

Extruded AluminumBeam Pipes with sidepumping chamber

Alternating-GradientPole Tips (no Quadrupoles)Ístructure is continuous in long lengths

LHe

75 kA SuperconductingTransmission Line

HeliumReturnLine

SupplyLine

Current Return

Cryopipes for Ring-Wide Distribution ofSingle-Phase Helium

KEY FEATURES:• Simple Cryogenic System• Small Superconductor Usage• Small Cold Mass• Low Heat Leak• Continuous in Long Lengths• No Quads or Spool Pieces• Warm Bore Vacuum System• Standard Construction Methods

Structural Support Tube/CryoLineVacuum Jacket

Transmission Line Magnet


��


Muon ColliderMuon Collider

Goal is a multi-TeV muon collider Two Machines under study

• Energy: 200 x 200 GeV 1.5 TeV x 1.5 TeV• Luminosity: 1x1033 cm-2s-1 5x1034 cm-2s-1

• Circumfrence: 1 km 6 km

Attractive Features:• Muons don't radiate as much as electrons

• Much smaller beam energy spread (∆p/p ~ 0.003%)• Easier to accelerate muons to higher energies

• Muons have large coupling to Higgs-like particles• Possible to study direct Higgs production

• Muon Colliders are compact• Muon Colliders can produce intense neutrino beams

Fermilab

10 Km

NLC

LHC(14 TeV p−p)

VLHC(60 TeV p−p)

NMC(4 TeV µ+µ−)

FMC (0.5 TeV µ+µ−)

(0.5 − 1.0 TeV e+e−)

Muon Colliders can be made very compact 4

For example, at least 2 generations of collider would fit on the Fermilab Site:

A good reason to suspect that if feasible a muoncollider will be significantly cheaper than alternative futuristic high energy colliders.

�

�

Pion Production Target and Capture Solenoid

Pion DecayChannel

Muon IonizationCooling Channel

Muon Accelerators

??????????

??????

Muon Collider

Proton Accelerator

16 GeV/c

100 MeV/cmuons

1.5 x 1022 protons / year

1.5 x 1021 muons / year

Up to 2 TeV/cmuons

..

..

..

..

..

..

..

..

..

Up to 2 x 2 TeV

µ+ µ−

??????

10 GeVmuons

Stopped/LowEnergy Muons

Neutrinos frommuon storagerings

Intense High−Energy Muon &Neutrino Beams

Higgs, t t , WW, ...

Intense K Physics

5 Muon Collider Schematic

6

PHOTO DATE: OCTOBER 1997


Muon Collider ChallengesMuon Collider Challenges

Requires high power (4 MW) proton beam on a target with efficient production and capture

• Studies ongoing at the AGS (Brookhaven)

Requires rapid cooling and acceleration• Test of all critical components planned at Fermilab

followed by eventual construction of short cooling section

Other challenges (less severe):• RF, magnets, accelerator design, collider ring,

detector• R&D plans exist for all of these

2 0

● Within the framework of two−flavor oscillations, the flavor eigenstates (να & νβ)are related to the mass eigenstates (νi & νj)by :

● The probability that, whilst traversing L(km), a να oscillates into νβ is given by:

Where Eν is in GeV, & ∆mij2 = mj2 − mi

2 (eV2/c4)

● Within the framework of 3−flavor oscillations, themixing is described by a 3x3 CKM−like matrix

Neutrino Oscillations

να = νi cos θ − νj sin θνβ = νi sin θ + νj cos θ

P(να −> νβ) = sin2(2θ) sin2(1.267∆mij2 L/Eν)

● To fully determine the mixing matrix ideally would like to measure the parameters for all να & νβ −> NEED νe AND νµ beams !

νανβνγ

νiνjνk( () ))(3 x 3=


MINOS - Long Baseline Neutrino Oscillations

MINOS - Long Baseline Neutrino Oscillations


MINOS Measurement PotentialMINOS Measurement Potential

Calculated MINOS limits on Neutrino Oscillations plotted vs. neutrino mass difference and neutrino mixing angle

Colored plots show regions consistent with data on oscillations from atmospheric neutrino detector measurements


The far futureThe far future

Many new developments in accelerator technology

Example: Plasma-based Linac• Driver: electron beam or laser• Wake generation: electron surfs on plasma electric

field

Recent Advances:• High unstable gradients demonstrated: > 100 GeV/m• Acceleration of injected electrons in Laser Wakefield

• 1.5 GeV/m, 1.5 MeV acceleration

Next steps:• Higher power stable laser drivers• Beam drivers: ultra-relativistic dynamics in plasma


High Energy Physics in the 21st Century

High Energy Physics in the 21st Century

Roadmap to discovery:

New Facilities Operating:• 2005 - 25: Large Hadron Collider• 2010 - 30: Next Linear Collider• 2015 - 35: Muon Collider, Very Large Hadron Collider• 2025 - : Exotic Machines: Plasma Acceleration....

New Physics:• Higgs• Supersymmetry• Guidance towards a Grand Unified Theory• What we would never expect????

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Experimental High Energy Physics in the Next Centuryhep.wisc.edu/wsmith/Dept_Cent.pdf · 1999. 10....

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