1. Higgs and SUSY at an e+e- Linear Collider

2. Towards Physics at the Linear Collider
Naturalness gives an indication
on the scale of New Physics, once
mH is known;
Expect Higgs discovery at
Tevatron or LHC
EW data from LEP/SLC/Tevatron
indicate that mH is light, or there
is New Physics of certain specific
types [Peskin, Wells, 2001]:
if mH < 180 GeV rich program
of precision mapping of Higgs
profile at ILC;
if NP, ILC/CLIC best suited
for detailed mapping through
EW data + direct searches.
mH < 182 GeV

3. Studying NP at Colliders beyond LHC
ILC to provide point-like particle
collisions from 0.3 TeV up to ~ 1 TeV
with tunable centre-of-mass energies,
particle species and polarization states;
In a farther future, CLIC multi-TeV
e+e- collider may further push energy
frontier up to 3 – 5 TeV.

4. ILC Energy Accelerating Gradient vs. RF Frequency: [ILC 0.5 – 1.0 TeV]
[CLIC TeV]
CLIC
ILC

5. Progress with S.C. Cavity Gradient

6. Towards Detailed Analyses
Essential to validate anticipated results with
analyses based on full G4 simulation and
reconstruction;
LC physics program presents significant
challenges to detector design and
machine-detector interface to preserve
the signature e+e- clean event reconstruction;
Parallel effort in providing reconstruction
tools with required precision;

7. Benchmarks for the ILC Develop list of benchmark processes where
i) ILC physics scenarios broadly covered, ii) benchmarks robust and retain
wider scope, iii) detector performance manifest in direct way, iv) target
performance motivated by quantitatively well-defined requirements.

8. Benchmarks for the ILC

9. ILC Physics Signatures
ILC Physics program has possibly the broadest range of particle
kinematics and event topologies;
Within a single physics scenario, DM-motivated Supersymmetry,
below are some of the signal signatures which need to be measured
with O( %) accuracy:

10. Higgs Sector Profile at ILC
T Barklow, hep-ph/

11. H0gbb, cc, gg at TeV
Determination of Higgs hadronic branching fractions, one of the most crucial
tests of the Higgs mechanism of mass generation and unique to the ILC for
the experimental accuracy needed to match theory uncertainties and probe
extended Higgs sector models;

12. H0gbb, cc, gg at TeV
Determination of Higgs hadronic branching fractions, one of the most crucial
tests of the Higgs mechanism of mass generation and unique to the ILC;
Light Higgs boson offers opportunity and challenge: couplings to b, c and t
quark accessible, but need to tag b, c, light jets with 70 : 3 : 7 ratio in signal.
120GeV
dBR(HgX)/BR
Hgbb
Hgcc
Hggg
Kuhl, Desch
LC-PHSM

13. H0gbb, cc, gg at 0.35 - 0.5 TeV Hgbb Hgcc Hggg + 0% +15% + 5% spoint:
Channel
Change
Rel. Change in
Stat. Uncertainty
Hgbb
Hgcc
Hggg
Geometry:
5 g 4 layer VTX
Thickness:
50 mm g 100 mm
+ 0%
+15%
+ 5%
spoint:
4 mm g 6 mm
4 mm g 2 mm
+10%
-10%
Yu et al.
J. Korean Phys. Soc. 50 (2007);
Kuhl, Desch
LC-PHSM ;
Ciborowski,Luzniak
Snowmass 2005
Degradation in performance correspond to 20-30%
equivalent Luminosity loss.

14. H g t+t- and m+m- dgHtt/gHtt dgHmm/gHmm
Determination of gHmm coupling important to test Higgs mechanism in
lepton sector, high energy e+e- collisions offer a unique opportunity;
Sensitivity being assessed for 0.35 – 0.5 TeV
in Higgstrahlung process,
Process accessible in WW fusion
at higher energy,
precision measurement in
multi-TeV collisions:
Ecm
TeV MH
120
140
150
dgHtt/gHtt
0.5
0.027
0.050
dgHmm/gHmm
0.8
0.150
3.0
0.042
0.065
0.12
MB, 2002

15. e+e- g neneHgm+m- at 3 TeV
s(e+e-gHnn) = 0.51 pb
for MH=118.8 GeV, Ecm = 3 TeV
BR(Hgmm) = %
SM Background
s(e+e-gmmnn) = 4.7 fb
Mokka+Marlin
SiD Model 3 TeV
Preliminary
Analysis performed using
SiD model in MOKKA 06-01
and Marlin ;
Results for 3 ab-1
Signal
179 29
dgHmm/gHmm
0.042
MB, 2007

16. e+e-g nnH0gbb at 1 TeV Large WW fusion cross section
at large Ecm gives access to gHbb
over full range compatible with
LEP-2 +EW data:
For mH = 200 GeV, Hgbb becomes
rare decay (2 x 10-3), still ILC at 1 TeV
can get its branching fraction to 9%
accuracy:
T Barklow

17. Determining the Higgs Potential
Fundamental test of Higgs
potential shape through independent
Determination of gHHH in double
Higgs production
Opportunity unique to the ILC,
LHC cannot access double H
production and SLHC may have
only marginal accuracy;
several LC analyses pioneered by
P. Gay et al.

18. HH Mass Decay Angle Double Higgstrahlung at 0.5-0.8 TeV
Double WW Fusion at 1-3 TeV
HH Mass
Decay Angle
MB, Boos, Yao, 2005

19. Barklow, LCWS07

20. e+e- gH0H0Z0 at 0.5 TeV with LDC
Isolating HHZ signal (s=0.18fb) from
tt (s=530fb), ZZZ (s=1.1fb),
tbtb (s=0.7fb) and ttZ (s=0.7fb)
is an experimental tour-de-force;
b-tagging and jet energy resolution
essential to suppress backgrounds;
Boumediene, Gay,
LCWS07

21. e+e- gH0H0Z0 at 0.5 TeV with LDC
Understand impact of detector
performance on triple Higgs
couplings determination accuracy
at ILC
Parametric
Simulation
L = 2 ab-1
Boumediene, Gay,
LCWS07

22. e+e- gH0H0Z0 at 0.5 TeV with SiD
Re-analysis of HHZ production
with realistic, yet parametric
simulation of SiD detector and
full SM backgronds;
Emphasis of Particle Flow
performance and algorithm
optimisation;
Barklow, LCWS07

23. The Higgs Profile and the Physics beyond
In models with extended Higgs sector, such as SUSY, Higgs
couplings get shifted w.r.t. SM predictions:
Desch et al.,
hep-ph/

24. The Effect of
Theory Uncertainties
Droll, Logan,
PRD76 (2007)

25. Invisible Higgs Decays
In ADD model mixing of Higgs and KK graviscalar and H decay in
graviscalar pairs generate invisible width which can be detected at ILC;
Study of invisible H decay and at ILC allows to tightly
constrain model parameters:
LHC
ILC
MB, Dominici, Gunion, Wells, LCWS05

26. Invisible Higgs Decays
Radion mixing in RS models
shifts Higgs couplings;
Possible reduction of Higgs
yields at LHC but clear
signature in ILC data from
precision data on bb and WW
couplings:
MB, De Curtis, Dominici et al., PLB568 (2003)

27. DM-motivated SUSY at ILC
If DM due to WIMPs manifesting New Physics beyond SM,
next generation of hadron (LHC, SLHC) and lepton collider (ILC, CLIC)
expected to discover direct signal of this NP and perform detailed studies;
Collider data will combine with direct searches and satellite experiments
to understand DM properties from microscopic to macroscopic scales;
Supersymmetry offers attractive framework to study opportunities at
colliders experiments;

28. Model Independent WIMP Detection at ILC
Irreducible SM bkg
removed by using polarised beams
Analysis performed with full G4
simulation and reconstruction;
C Bartels, J List

29. Model Independent WIMP Detection at ILC
Alternatively, use photon spectrum
directly and scan Mc – annihilation
fraction;
Assume beam polarisation, realistic
ECal resolution;
Konar, Matchev, Perelstein et al

30. Solving the SUSY Inverse Problem
Resolve the degeneracies arising by
reconstructing fundamental parameters
from LHC experimental observables;
Arkani-Hamed, Kane, Thaler, Wang,
hep-ph/
242 models with 164 degenerate pairs at LHC
82 models, 72 pairs visible at 0.5 TeV ILC;
55 pairs distinguishable at ILC;
75% of accessible model pairs degenerate
at LHC can be solved at LC, but large Ecm
essential
Study LHC-degenerate models
at 0.5 TeV and 1 TeV ILC,
J Hewett, T Rizzo, Gainer et al.

31. Cosmologically interesting cMSSM Regions and Benchmark points
Systematic study of ILC reach promoted by
US study group on ILC-Cosmo Connections
Cosmologically interesting
cMSSM Regions and Benchmark points
Compute RGEs with Isajet 7.69 and
estimate dark matter density from
Isajet spectrum and couplings with
MicrOMEGAS 1.3 and DarkSUSY 4.0
J Ellis, K Olive, MB, M Peskin,…

32. Constraining the Higgs Sector with WCDM
Allanach et al.,hep-ph/

33. SUSY Bulk Region Heavy part of SUSY spectrum decouples
from Wc determination
LCC1
Benchmark

34. A Comparison of DM density accuracy at LHC and ILC in Bulk Region
WMAP
Baltz,MB,Peskin,Wizanski,
PRD74 (2006)
but bulk region not quite representative of SUSY phase space...

35. in Baryogenesis motivated Scenarios
Stop co-Annihilation
in Baryogenesis motivated Scenarios
Light scalar top, nearly degenerate
with neutralino, provides efficient
co-annihilation and evades
Tevatron searches due to small ET.
LHC
ILC
Baryogenesis constraints push
towards heavy scalar and
introduces CP-violating phase in m.
Scenario shares several features
characteristic of FP region but
requires analysis of real Z0 and light stops.
Carena, Freytas, hep-ph/

36. Heavy Higgses at LHC/SLHC and DM
F Gianotti

37. Heavy Higgs Sector in MSSM
DM (GeV)
DG (GeV)
0.24
1.5
Desch et al., hep-ph/

38. Heavy MSSM Higgses , Wch2 and LCC4

39. The Higgs Sector of the LCC4 Point
LCC4 point in A0 Funnel region
Benchmark point defined in cMSSM
LCC4 Benchmark

40. Selection Criteria General selection cuts:
at least 4 hadronic jets (JADE algorithm)
(at least 5 ptc/jet);
force event to 4 jets;
apply di-jet btagging;
reconstruction Efficiency = 40 %
Ncha > 20
Ntot > 100
Echa > 250 GeV
Etot > 850 GeV
ET > 350 GeV
y34 <
Thrust < 0.96
Mjj > 150 GeV

41. Selection Criteria
Etot

42. 4-jet Kinematic Fit
Perform constrained kinematic fit to 4-jet system, which uses Lagrange
multipliers and minimises a c2 constructed from the measured energies
and directions of the jets;
Impose centre-of-mass energy and
momentum conservation;
Consider jj jj pairing giving smallest
mass difference and plot di-jet
masses Mjj (2 entries / evt);
Port of PUFITC+ developed for
DELPHI at LEP2 (N Kjaer, M Mulders)
to MarlinReco framework
MB, Hooberman

43. to Parametric Simulation
Compare Full G4+Reco
to Parametric Simulation
SIMDET
G4+Marlin
SIMDET
Fast Simulation
Full G4+
MarlinReco
Preliminary
MB, LCWS04
MB, Hooberman, LCWS07

44. Further DM Constraints from HA
BR(A gbb)
Analysis of Markov Chain
MSSM scans to identify
further observables to
possibly improve DM
density determination at
the ILC

45. t t A0 Branching Fraction Determination b b b b b b
Contrast bbtt to bbbb based on missing energy,
nb. of hadronic jets and jj+recoil masses;
bbtt Reconstruction Efficiency 35% b b b
Determine BR(Agtt) from rate of bbtt to bbbb
tags, WW + ZZ background appears small; b
Expect ~ 0.15
~0.07 t t b

46. Stau Tri-linear Coupling - Atau
Constrain Atau through
H g tt decays:
Stau Couplings to H/A: ~~
Atau A H
In A funnel, MA<Mt1+Mt2
and the only such decay
allowed by CP for the
pseudoscalar Agt1t2 is
not available;
Heavy H0 gt1t1 scales with Atau and can be used to constrain
stau trilinear coupling in this regime.

47. Stau Tri-linear Coupling - Atau
H/A Branching Ratios vs Atau
Atau scan for LCC4
MSSM parameters
with HDECAY 2.0
Large Hgt1t1 can
be detected by standard
bbtt + bbbb analysis
and used to constrain
Stau trilinear coupling

48. for LCC4 with HA analysis
DM density accuracy
for LCC4 with HA analysis
Phys.Rev.D74:103521,2006.
MB, Hooberman, Kelley

49. Collider Experiments on Dark Matter
Dark Matter Density
g0.08
Baltz, MB, Peskin, Wiszanski, PRD74 (2006)

50. within MSSM on cMSSM plane
dW/W ILC Accuracy
within MSSM on cMSSM plane
0.08
0.18
J Ellis, K Olive, MB et al.