FZÚ, 12.5.2005 J. Cvach, LCWS05 1

LCWS 051. LHC a ILC

2. Top

3. Higgs

4. Polarizace

FZÚ, 12.5.2005 J. Cvach, LCWS05 2

The TeV ILC planned for 2015

• Parameters defined by ILCSC scope-panel for ITRPhttp://www.fnal.gov/directorate/icfa/LC_parameters.pdf

• Baseline s = 200-500 GeV, • integrated luminosity = 500 fb-1 over 1st 4 years• 80% electron polarisation• 2 interaction regions with easy switching

• Upgrade Anticipate s 1 TeV, = 1 ab-1 over 4 years

• Options e-e- collisions, • 50% positron polarisation,• “GigaZ”; high at Z and at WW threshold,• Laser backscatter for and e collisions,• Doubled at 500 GeV.• Choice among options to be guided by physics needs.

FZÚ, 12.5.2005 J. Cvach, LCWS05 3

Physics at the LHC and ILC in a nutshell

LHC: pp scattering at 14 TeV

Scattering process of protonconstituents with energy up toseveral TeV,strongly interacting huge QCD backgrounds,

low signal-to-backgroundratios

ILC: e+e- scattering at ≈ 0.5-1 TeV

Clean experimental environment:• well-defined initial state,• tuneable energy,• beam polarization, GigaZ

γγ, γe-, e-e- options, . . . relatively small backgrounds

high-precision physics

FZÚ, 12.5.2005 J. Cvach, LCWS05 4

Why?

2001; mt=174.3 5.1; PDG

2004; mt=178.0 4.3

Moves best fit mH

by > 20 GeV. Very sensitive.

Recent illustration; D0’s new mt measurement

Because precision on mt limits current SM fit.

Definite job to be done.Measure mt to < 100 MeV

FZÚ, 12.5.2005 J. Cvach, LCWS05 5

(Heinemeyer et al)

What precise mt would do for MSSM

FZÚ, 12.5.2005 J. Cvach, LCWS05 6

Flavour changing NC processes

FZÚ, 12.5.2005 J. Cvach, LCWS05 7

High precision top mass

FZÚ, 12.5.2005 J. Cvach, LCWS05 8

Higgs na ILC

Hlavní mechanismy pro produkci Higgse :

a) Higgs strahlung (dominuje pro malé MH)

b) W fusion (dominuje pro velké MH)

FZÚ, 12.5.2005 J. Cvach, LCWS05 9

500 fb-1 at350 GeV

Constrained fits to final states

0

120HM GeV

H Z bbqq

0

120HM GeV

H Z bbl l

0

150HM GeV

H Z W W qq

0

150HM GeV

H Z W W l l

Higgs mass measurement

FZÚ, 12.5.2005 J. Cvach, LCWS05 10

TESLATDR

Precision on Higgs branching ratios

FZÚ, 12.5.2005 J. Cvach, LCWS05 11

The Recoil Measurement

Higgs mass and cross section in e+e- Z X e+e- X (μ+μ- X)• Study of SM Higgs sensitivity at ILC - full simulation

(MOKKA)!• work in progress

Event display: h0 Z0 b bbar μ+ μ-

Particle Flow in Reconstruction The Invariant Mass of Invisible System (the Recoil Mass Method) Including the ISR

SM Higgs Signal Reconstruction Z μ+ μ- Final State 100 fb-1

SM Higgs Signal Reconstruction Z e+e- Final State 100 fb-1

FZÚ, 12.5.2005 J. Cvach, LCWS05 12

ILC Charge in Higgs Physics

At the ILC, we can do an inclusive measurement of Higgs production:

e+e- H + X (recoil spectrum)

This removes the model dependence from all LHC (and ILC) coupling measurements.

• At the ILC, we can determine couplings to better than 5 %. In particular, can be precisely measured.

Leaving the minimal SM paradigm, there is another crucial point:

• At the ILC, we can detect extra scalars in the Higgs sector (if not too heavy), complementing LHC searches. Many of their properties can be determined.

Finally:

• At the ILC, the Higgs self-coupling can be measured (with low precision), if the Higgs is not too heavy. (For a Higgs boson above the WW threshold, this is more accessible at the LHC.)

H→bb

FZÚ, 12.5.2005 J. Cvach, LCWS05 13

"Known unknowns" vs. "unknown unknowns"

ILC will be prepared to explore Higgs physics, SUSY, extra dimensions, mini black holes, . . .

These are „known unknowns“, but one also needs to be prepared for the unexpected

LHC: interaction rate of 109 events/s

can trigger on only 1 event in 107

ILC: untriggered operation

can find signals of unexpected new physics (direct production + large indirect reach) that manifests itself in events that are not selected by the LHC trigger strategies

FZÚ, 12.5.2005 J. Cvach, LCWS05 14

Práce skupiny LHC/ILC: hep-ph/0410364

The intimate interplay of the results of the two collider facilities will allow one to probe, much more effectively and more conclusively than each machine separately, the fundamental interactions of nature and the structure of matter, space and time.

Results from both colliders will be crucial in order to decipher the underlying physics in the new territory that lies ahead of us and to draw the correct conclusions about its nature. This information will be decisive for guiding the way towards effective experimental strategies and dedicated searches. It will not only sharpen the goals for a subsequent phase of running of both LHC and LC, but will also be crucial for the future roadmap of particle physics.

The interplay between LHC and LC is a very rich field, of which only very little has been explored so far.

FZÚ, 12.5.2005 J. Cvach, LCWS05 15

Positron (polarised) source

• Both beams polarized– Different production mechanisms in s, t channels– In case of MSSM – charge of observed lepton directly

related to L, R quantum no. of the selectron• e-

L,R ẽ-L,R and e+

L,R ẽ+L,R

– Smaller background to physical processes

• Large amount of charge to produce• Three concepts:

– undulator-based (TESLA TDR baseline)– ‘conventional’ (extrapolation from SLC e+ source)– laser Compton based

FZÚ, 12.5.2005 J. Cvach, LCWS05 16

Undulator-Based

6D e+ emittance small enough that (probably) no pre-DR needed [shifts emphasis/challenge to DR acceptance]

Lower n production rates (radiation damage)

Need high-energy e- to make e+ (coupled operation) Makes commissioning more difficult

Polarised positrons (almost) for free

FZÚ, 12.5.2005 J. Cvach, LCWS05 17

Compton Source (KEK)

FZÚ, 12.5.2005 J. Cvach, LCWS05 18

Damping ring – „ochlazení svazku“

33km47 km

TESLA TDR500 GeV (800 GeV)

US Options Study500 GeV (1 TeV)