Post on 28-Dec-2015
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
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
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
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
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
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
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
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 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
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
gHHH
Precision Higgs physics
Reconstruction of the Higgs potential
Δλ/λ ~ 10-20 % for 1 ab-1
Only possible at ILC
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