Role of Accelerators . . .

R.-D. Heuer (Univ. Hamburg/DESY) ICFA Seminar 2005, Daegu, Korea

. . . in “Dark World”

Role of Accelerators . . .

R.-D. Heuer (Univ. Hamburg/DESY) ICFA Seminar 2005, Daegu, Korea

. . . in “Dark World”

Focus on energy frontier colliders LHC and ILC

- expect wealth of information at the terascale

- expect first discoveries in the dark world

Nature’s accelerators

TeV-Gamma-RayRadioX-Ray

… a new source class: “Dark Accelerators”

Three sources known

Lesson: need instruments in different wavelength regimes

to understand physics of sources and accelerators

• extended• hard spectra• steady emission

(from T. Lohse, EPS2005)

Multi-Messenger Astronomy

protons

-rays

neutrinos

gravitational waves

Lesson: need different instruments and methods

to probe the high-energy Universe

even further:

13 Sensitivity in the Next Generation

NOvA

T2K

Compare:• 5 years each • 5% flux uncertainty

next generation long baseline experiments

coming long baseline experiments

1 reactor +2 detectors

NOA

Huber, ML, Rolinec, Schwetz, Winter

From M. Lindner

Particle Colliders

Aaaaaa

“optimistic scenario”

(from F.Zimmermann, EPS05)

future

“Standard Model era” “Dark World era”

“Discovery” of Standard Model

through synergy of

hadron - hadron colliders

lepton - hadron colliders

lepton - lepton colliders

Particle Accelerators

Both strategies have worked well together → much more complete understanding than from either one alone

There are two distinct and complementary strategies for gaining understanding of matter, space and timeat particle accelerators

HIGH ENERGY direct discovery of new phenomena i.e. accelerators operating at the energy scale of the new particle

HIGH PRECISION interference of new physics at high energies through the precision measurement of phenomena at lower scales

Synergy of colliders

prime example: LEP / Tevatron

knowledge obtainedonly through combination of results from different accelerator types

in particular:Lepton and Hadron Collider

Time evolution ofexperimental limits on the Higgs boson mass

Synergy of colliders:

MH between 114 and ~200 GeV

LEP,SLD,Tevatron…

indirect

direct

top

History of the Universe

LHC, ILCRHIC,HERA

extrapolation via precision

e+e-

e-proton

proton-proton

today1970 1980 1990 2000 2010 2020 2030

LHC

ILC

TEVATRON

HERA

LEP,SLC

PEP-II, KEKB

VEPP, CLEO-c, BEPC

DANE

FNAL, CERN, J-PARC

Energy Frontier Colliders:

Flavor Specific Accelerators:

e+e- (b factory)

e+e- (c factory)

e+e- (s factory)

CLIC

Collider

LHCb

from Y-K. Kim

why LHC and ILC

p p e+ e-

p = composite particle:unknown s of IS partons,no polarization of IS partons,parasitic collisions

p = strongly interacting:large SM backgrounds,highly selective trigger needed,radiation hard detectors needed

e = pointlike particle:known and tunable s of IS particles,polarization of IS particles possible,kinematic contraints can be used

e = electroweakly interactinglow SM backgrounds,no trigger needed,detector design driven by precision

Explore new Physics through high precision at high energy

microscopic telescopic

( )new SMe e X Y e e SM

Study the properties ofnew particles(cross sections,BR’s, quantum numbers)

Study known SM processesto look for tiny deviationsthrough virtual effects(needs ultimate precisionof measurements andtheoretical predictions)

precision measurements will allow -- distinction of different physics scenarios -- extrapolation to higher energies

the role of LHC and ILC

SOME COSMOLOGICAL PARAMETERS

B

CDM

DE

DECDMBTOT

THE ENERGY DENSITY BUDGET

BARYONS

COLD DARK MATTER

NEUTRINOS

DARK ENERGY

• around 23% is in some mysterious “dark matter”. It clumps, but not as tightly as ordinary matter.

• around 73% is in some mysterious “dark energy”. It is evenly spread, as if it were an intrinsic property of space. It exerts negative pressure.

• ordinary matter contributes only about 5% of the total mass in the Universe. This makes stars, galaxies, nebulae, ...

Standard Model works very well

Challenge: explore the world of dark matterby creating it in the laboratory

Dark Matter

Astronomers & astrophysicists over the next two decades using powerful new telescopes will tell us how dark matter has shaped

the stars and galaxies we see in the night sky.

Only particle accelerators can produce dark matter in the laboratory and understand exactly what it is.

Composed of a single kind of particle or

as rich and varied as the visible world?

LHC and ILC may be perfect machines to study dark matter.

from Y-K Kim (modified)

Supersymmetry

● unifies matter with forces for each particle a supersymmetric partner (sparticle) of opposite statistics is introduced

● allows to unify strong and electroweak forces sin2

WSUSY= 0.2335(17)

sin2W

exp = 0.2315(2)

● provides link to string theories

● provides Dark Matter candidate

Mass spectra depend on choice of models and parameters...

Supersymmetry

well measureable at LHC

precise spectroscopyat ILC

from F. Gianotti (LP05)

LHC

LHC

Bourjaily,Kane, hep-ph/0501262

LSP responsible for relic density ΩCDM ?

need to measure many parameters, in particular coupling to matter

Measurement of sparticle propertiesmasses, couplings, quantum numbers,…

ex: Sleptons

lepton energy spectrum incontinuum

ex: Charginos threshold scan

achievable accuracy: δm/m ~ 10-3

ILC

LHC and ILC

MSSM parameters from global fit

only possible with information from BOTH colliders

Sparticles may not be very light

Lightest visible sparticle →

← S

econd lightest visible sparticle

JE + Olive + Santoso + Spanos

BUT

LSP light in most cases

Lightest visible sparticle →

← S

econd lightest visible sparticle

Aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

AaaaaaaaaaaaaaaaLightest invisible sparticle →

Lig

htes

t vis

ible

spa

rtic

le →

Kalinowski

Aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

AaaaaaaaaaaaaaaaLightest invisible sparticle →

Lig

htes

t vis

ible

spa

rtic

le →

Kalinowski

1000

1500

e+e- χ1χ2

• consider pair production e+e-->χ1χ1

• χ invisible

• use photon radiated off e+ or e-

• Ωdm

=> σ (e+e-->χχγ) ≈ 0.1 .... 10 fb

~ 50....5000 events / 4 years ILC [A.Birkedal et al hep-ph/0403004]

• not trivial,

main background: e+e-->νν (+γ)

reduction through appropriate choice ofbeam polarisation

Model independent WIMP search ILC

ILC

Precision electroweak tests

As the heaviest quark, the top-quark could play a key role inthe understanding of flavour physics…..

…requires precise determination of its properties….

ΔMtop ≈ 100 MeV

Energy scan of top-quark threshold

ILC

But:connection to dark matter ?

Heinemeyer et al, hep-ph/0306181

mSUGRA

constrain allowed parameter space

Precision electroweak tests

δM(top) = 2 GeV

δM(top) = 0.1 GeV

constrain mass and interaction strength

Comparison with expectations from direct searches

Dark Matter and SUSY

If SUSY LSP responsible for Cold Dark Matter, need acceleratorsto show that its properties are consistent with CMB data

a match between collider and astrophysical measurements would provide overwhelming evidence that the observed particle(s) is dark matter

LHC and ILC

direct measurementof mass

indirect measurementof couplings

determine origin of particle

LHC and ILC results should allow, together with dedicated dark matter searches,first discoveries in the dark world• around 73% of the Universe is in some mysterious “dark energy”. It is evenly spread, as if it were an intrinsic property of space. It exerts negative pressure.

Challenge: get first hints about the world of dark energy in the laboratory

The Higgs is Different!

All the matter particles are spin-1/2 fermions.All the force carriers are spin-1 bosons.

Higgs particles are spin-0 bosons.The Higgs is neither matter nor force;

The Higgs is just different.This would be the first fundamental scalar ever discovered.

The Higgs field is thought to fill the entire universe.Could give some handle of dark energy(scalar field)?

Many modern theories predict other scalar particles like the Higgs.Why, after all, should the Higgs be the only one of its kind?

LHC and ILC can search for new scalars with precision.

From Y-K. Kim

LHC

from F. Gianotti (LP05)

ILC can observe Higgs no matter how it decays!

100 120 140 160Recoil Mass (GeV)

MHiggs = 120 GeV

Num

ber

of E

vent

s /

1.5

GeV

Only possible at the ILC

ILC simulation for e+e- Z + Higgswith Z 2 b’s, and Higgs invisible

Precision Higgs physics

Determination ofabsolute coupling values with high precision

gHHH

Precision Higgs physics

Reconstruction of the Higgs potential

Δλ/λ ~ 10-20 % for 1 ab-1

Only possible at ILC

From Yamashita

Precision Higgs physics and New Physics

Detailed studyof Higgs propertiespossible

LHC and ILC results will allow to study the Higgs mechanism in detail and to reveal the character of the Higgs boson

This would be the first investigation of a scalar field

This could be the very first step to understanding dark energy

DARK MATTER

DARK ENERGY

LHC and ILC together will allow first discoveries in the dark world

from GSF

Past decades saw precision studies of 5 % of our Universe Discovery of the Standard Model

The LHC will soon deliver data

Preparations for the ILC as a global project are well under way

We are just at the beginning of exploring 95 % of the Universe

Past decades saw precision studies of 5 % of our Universe Discovery of the Standard Model

The LHC will soon deliver data

Preparations for the ILC as a global project are well under way

We are just at the beginning of exploring 95 % of the Universe

the future is bright in the dark world