'
$
&
%

' $
• Senior personnel
• K. Matchev (UF, Cornell), (Anton, DOB August 2003)
• Postdocs
• A. Birkedal (UF, Cornell), (Austin, DOB July 2003)
• A. Datta (UF), (Anwoy, DOB April 2004)
• Graduate students
• K.C. Kong (UF), (TBA, EDC August 2004)
• C. Group (UF, 0.5 FTE, with R. Field).
• Undergraduate students
• J. Blender (Cornell), REU student at UF, Summer 2003
• T. Gleisberg (Dresden), diploma student at UF, Spring 2003.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 2
%

' $
• Many motivations for new physics, but... dark matter is our best evidence for new physics BSM: Ω
DM
= 0 .
23 ± 0 .
04.
• Questions to ask theorists:
Who is the dark matter in your theory/model and can you calculate its relic abundance?
How can we test this theory at the Tevatron/LHC/NLC?
• WIMPs: motivated by both particle and astrophysics.
• Predicted in many particle physics scenarios BSM.
• Give the right order of magnitude Ω
DM
.
Ω
DM h
2
∼ 0 .
1
σ
EW
σ ann
Is this simply a coincidence?
• Potentially observable signals in DM detection expts.
χ
χ SM
χ
=
⇒
χ
SM q q
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 3
%

' $
• Recipe for BSM dark matter
• invent a model with new particles
• invent a symmetry which guarantees a stable new particle
• fudge parameters until the lightest new stable particle is neutral and has the correct relic density
• Three generic examples of new physics with a DM WIMP
• supersymmetry: DM = lightest superpartner.
• extra dimensions: DM = lightest Kaluza-Klein mode.
• Little Higgs: DM = LPOP, LZOP? (billion, gatesino, ...)
• Brief review, discovery prospects
• How can we distinguish the different scenarios?
• in astroparticle physics experiments
• at high energy colliders
• How well can we test cosmology at the LHC/NLC?
• Does cosmology tell us anything about collider signals of new physics in a model-independent way?
• Outreach
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 4
%

' $
SUSY
UED n = 3
Little Higgs n = 2 n = 1
SM n = 0
SUSY UED Little Higgs
DM particle
Spin
Symmetry R
LSP
1/2
-parity
LKP
1
KK-parity T
LTP
0
-parity
Mass range 50-200 GeV 600-800 GeV 400-800 GeV
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 5
%

' $
• Supersymmetry is an extra dimension theory with new anticommuting coordinates θ
α
:
Φ( x
µ
, θ ) = φ ( x
µ
) + ψ
α
( x
µ
) θ
α
+ F ( x
µ
) θ
α
θ
α
• SUSY relates SM particles and their superpartners ( φ ↔ ψ )
• quarks, leptons ⇔ squarks, sleptons
• gauge bosons: g , W
±
, W
0
3
, B
0 ⇔ gauginos: ˜ w
±
• Higgs bosons: h
0
, H
0
, A
0
, H
± ⇔ higgsinos: ˜
± 0 u w
0 b
0
0 d
• The superpartners have
• spins differing by 1/2
• identical couplings
• unknown masses (model-dependent)
• Discovering new particles with those properties IS discovering supersymmetry
• The superpartners are charged under a conserved R -parity
• SM particles: R = +1
• superpartners: R = − 1 = ⇒ stable LSP (DM?).
• No tree-level contributions to precision EW observables
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 6
%

'
• The lightest neutralino ˜
0
1 is a mixture of b
0
, ˜
0
,
0
1
= a
1 b
0
+ a
2
˜
0
+ a
3
0 u
+ a
4
0 d
0 u
,
0 d
:
• Gaugino fraction R
χ of the LSP:
R
χ
≡ | a
1
|
2
+ | a
2
|
2
≈ | a
1
|
2
.
Feng,KM,Wilczek (2000)
$
• Focus point region: large m
0
, mixed LSP.
• Coannihilation region: small m
0
, τ ˜ − ˜
0
1 degeneracy.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 7
%

' $
Appelquist, Cheng, Dobrescu, hep-ph/0012100
• U niversal E xtra D imensions is an extra dimension theory with new bosonic coordinates y (spanning a circle of radius R ):
Φ( x
µ
, y ) = φ ( x
µ
) +
∞
X
φ n
( x
µ
) cos( ny/R ) + χ n
( x
µ
) sin( ny/R ) i =1
• Each SM field φ ( n = 0) has an infinite tower of Kaluza-Klein
(KK) partners φ n and χ n with
• identical spins
• identical couplings
• unknown masses of order n/R
• Remnant of p
5 conservation: KK -parity ( − 1) n
• KK = +1 for even n and KK = − 1 for odd n .
• lightest KK partner at level 1 (LKP) is stable.
P
3
→ P
0
3
P
0
, P
2
P
1
, P
1
P
0
;
P
2
→ P
0
2
P
0
, P
1
P
1
, P
0
P
0
;
P
1
→ P
0
1
P
0
.
• No tree-level contributions to precision EW observables
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 8
%

'
• The KK modes at each KK level n are extremely degenerate: m
2 n
= n
R
2
+ m
2
0
Cheng, KM, Schmaltz, hep-ph/0204342
$
• The radiative corrections are crucial for phenomenology, e.g.
m e
1
− ( m
γ
1
+ m e
0
) e
1
→ γ
1 e
0
?
∼ − R
− 1 m e
R − 1
∼ − R
− 1
• Lots of stable (charged, colored) heavy particles...
10
− 6
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 9
%

'
• Including radiative corrections, the mass spectrum of level 1 KK modes looks something like this:
Cheng, KM, Schmaltz, hep-ph/0204342
$
• Mimics supersymmetry: prompt decays!
• Seems difficult to discover at the LHC, but...
• W
1
±
, Z
1 have pure leptonic branchings!
• sin
2
θ
1
W
≈ 0 = ⇒ γ
1 ≈ B
1
, similar to ˜ in SUSY.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 10
%

'
• Mass matrix for the neutral gauge bosons n
2
R 2
+ 1
4 g
2
1 v
2
1
4 g
1 g
2 v
2
2
B n n
2
R 2
+
1
4 g
1 g
2 v
2
1
4 g
2
2 v
2
• The Weinberg angle θ n at KK level n
γ n
= cos θ n
B
0 n
+ sin θ n
W
0 n
≈ B
0 n
.
2
W n
!
Cheng, KM, Schmaltz, hep-ph/0204342
$
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 11
%

'
• Relic density: G.Servant, T.Tait, hep-ph/0206071
5d
1 Flavor
3 Flavors
Ω h
2
= 0.110
±
0.006
$
∆
= .05
∆
= .01
m
KK
(TeV)
• Unlike supersymmetry: no helicity suppression
Ω h
2
=
1 .
04 10
9
M
P
√
GeV g
∗
− 1 x
F a + 3 b/x
F
; x
F
=
M
KK
T
F a =
α
2
1
M 2
KK
380 π
;
81 b = −
α
2
1
M 2
KK
95 π
.
162
• Unlike supersymmetry: coannihilation lowers the bound
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 12
%

' $
• The hierarchy problem in the SM h
Higgs
λ h h
W, Z, γ h h
λ t
Top g 2
λ t h
• Introduce new particles at TeV scale to cancel the one-loop quadratic divergences
λ t f h
H 0
−
λ h h
W 0 , Z 0 , γ 0
− g 2
χ
L
χ
R h h
−
λ t
/ (2 f )
• Conserved T -parity (Cheng, Low hep-ph/0308199)
• T = +1 for SM particles , T = − 1 for new particles .
• the lightest T -odd particle is stable.
• No tree-level contributions to precision EW observables h
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 13
%

' $
• If the lightest T -odd particle is a scalar, it can be a mixture of an SU(2)-triplet φ
0
3 and an SU(2)-singlet η
0
1
:
N
1
= cos θ
ηφ
η
0
1
+ sin θ
ηφ
φ
0
3
Birkedal-Hansen, Wacker hep-ph/0306161
1000
800 m
N
1
(GeV)
600
400
200
0 0.2
0.4
cos 2
θ
ηϕ
0.6
0.8
1
• The absence of helicity suppression requires large masses for the WIMP case.
• For 150 GeV < m
N
1
< 350 GeV, annihilation into t t and hh is very efficient.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 14
%

' $
• The estimated SUSY reach at various colliders
Baer, Krupovnickas, Tata hep-ph/0405058 mSugra with tan
β
= 30, A
0
= 0,
µ >
0, m t
= 180 GeV
1600
l 0.095
< Ω h
2 <
0.129
l
Ω h
2 <
0.095
1400
1200
1000
800
600
LHC
LC1000
400
200
0
0
LC500
Tevatron
~ m(W
1
)
<
103.5 GeV
2000 4000 6000 8000 m
0
(GeV)
10000 12000 14000
• When do we know we have seen supersymmetry?
• Many superpartners: can we count squark, slepton species?
• Spins?
• Couplings?
σ × BR , confusion, PDF uncertainty...
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 15
%

'
30
20
10
0 gluino
Battaglia et al., hep-ph/0306219 squarks sleptons
χ
H
LHC LC 0.5 TeV
30
20
10
0
L B G I C J HM A E F K D L B G I C J HM A E F K D
LC 1.0 TeV
30
20
10
0
L B G I C J HM A E F K D
CLIC 3 TeV
30
20
10
0
L B G I C J HM A E F K D
LHC+LC 1 TeV
30
20
10
0
L B G I C J HM A E F K D
CLIC 5 TeV
30
20
10
0
L B G I C J HM A E F K D
• Squarks are difficult to count:
• can be mistaken for gluinos
• ˜
R decays mostly give jets
• Many more 1st gen. ˜ q ’s.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 16
$
%

'
• Allowed dominant transitions
$
• KK gluon: B ( g
1
→ Q
1
Q
0
) ' B ( g
1
→ q
1 q
0
) ' 0 .
5.
• Singlet KK quarks: preferentially q
1
→ γ
1 q
0
• Doublet KK quarks:
B ( Q
1
→ W
±
1
Q
0
0
) ∼ 65% B ( Q
1
→ Z
1
Q
0
) ∼ 33%
• KK W - and Z -bosons: only leptonic decays!
• KK leptons: 100% directly to the LKP.
• At hadron colliders we want: strong production, weak decays!
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 17
%

' $
4 `
T
• Arises from inclusive Q
1
Q
1 production: Q
1
→ Z
1
→ `
±
`
∓
γ
1
• Tevatron triggers
• Single lepton p
T
( ` ) > 20 GeV, η ( e ) < 2 .
0, η ( µ ) < 1 .
5.
• Missing energy /
T
> 40 GeV.
• Tevatron cuts
• p
T
( ` ) > { 15 , 10 , 10 , 5 } GeV, | η ( ` ) | < 2 .
5.
• /
T
> 30 GeV.
• Invariant mass of OS, SF leptons: | m
``
− M
Z
| > 10 GeV, m
``
> 10 GeV.
• Main background: ZZ → `
±
`
∓
τ
+
τ
− → 4 ` /
T
. Not a problem.
• LHC cuts (pass the single lepton trigger)
• p
T
( ` ) > { 35 , 20 , 15 , 10 } GeV, | η ( ` ) | < 2 .
5.
• /
T
> 50 GeV.
• Invariant mass of OS, SF leptons: | m
``
− M
Z
| > 10 GeV, m
``
> 10 GeV.
• LHC backgrounds: multi-boson, ttZ , fakes, etc.
Assumption: 50 events/year (100 fb
− 1
).
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 18
%

'
• Discovery reach in the Q
1
Q
1
→ 4 ` /
T channel.
Cheng, KM, Schmaltz, hep-ph/0205314
$
• Typical signatures include:
• soft leptons, soft jets, not a lot of /
T
• a lot of missing mass (LHC can’t measure it)
• B ( Q
1
→ 2 ` /
T
+ X ) ∼ 1
9
. In principle, channels with W
1
’s can also be used – less leptons, but more often.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 19
%

' $
• Can you tell SUSY from UED?
• Yes. Tenth Conference on String Phenomenology in 2011.
J.Ellis hep-ph/0208109
• Look for the higher KK levels: e.g.
g
2 resonance.
• Single production of KK level 2 is suppressed (involves
KK-number violating couplings).
q
0 q
1 q
0 q
2 q
0 g
2 g
2 g
2 q
0
¯
0
¯
1
¯
0
¯
0
¯
0
¯
0
∼
55%
∼
35%
∼
10%
• g
2 appears a high mass dijet resonance. Z’ ?
• Pair production? Typically the rate is too small.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 20
%

'
Z
2
• Z
2 appears promising: Z
2
→ Q
1
Q
1 and Z
2
→ Q
2
Q
0 are closed.
Lots of hard leptons? No!
Z
2
→ Q
0
Q
0 wins over Z
2
→ `
0
`
0
.
• Z
2 branching fractions:
Datta,Kong,KM preliminary
$
• Z
2 also a high mass dijet resonance. Z’ ?
g
2
?
• Z
2 may also appear as a dilepton resonance, but
B ( Z
2
→ `
+
`
−
) ∼ 1%.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 21
%

'
γ
2
• γ
2 appears most promising. All γ
2
→ f
2 f
0 and γ
2
→ f
1 f
1 decays are closed. Every γ
2 decay dumps a lot of energy.
• γ
2 branching fractions:
Datta,Kong,KM (preliminary)
$
• γ
2 also a high mass dijet resonance. Z’ ?
g
2
?
Z
2
?
• In all cases the natural width is negligible compared to the detector dijet mass resolution.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 22
%

' $
• Inclusive search for high-mass dijet/dilepton resonances
• Recycle existing LHC analyses for Z
0 searches
• Rescale the background to account for the narrow width
• Reach for R
− 1 in GeV, assuming 100 fb
− 1
KK mode g
2
Z
2
γ
2 jj µ
+
µ
−
350 NA worse 350 worse 350 e
+ e
NA
400
400
−
• Can we discriminate the Z
2 and γ
2 resonances?
• Confusion: Supersymmetry plus one or more Z
0
?
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 23
%

' $
• Why COMPHEP?
• Spin correlations accounted for.
• Automated: ideal for new models which are straightforward generalizations of the Standard Model (UED, little Higgs).
• Once the Feynman rules are defined, any final state signature can be studied.
• It already has SUSY.
• It is interfaced to PYTHIA.
• The experimentalists know how to deal with it.
• What we have done so far:
• Level 1 is fully implemented with correct 1-loop masses.
Approximation: Z
1
≈ W
3
1
, γ
1
≈ B
1
. Widths: reasonable guess, but can be recalculated with COMPHEP.
• Level 2 fully implemented ( Z
2
≈ W
3
2
, γ
2
≈ B
2
, `
2
) with the correct widths.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 24
%

'
• The spin information is encoded in the angular distributions!
e
+ e
− → ˜
+ −
SUSY
→ µ
+
µ
− 0
1
0
1 e
+ e
−
UED
→ µ
+
1
µ
−
1
→ µ
+
µ
−
γ
1
γ
1 dσ d cos θ
∼ 1 − cos θ
2 d dσ cos θ
∼ 1 + cos
Datta,Kong,KM (preliminary)
θ
2
$
• Significant difference in the total cross-section as well!
• The masses can be extracted from the E
µ distribution.
• Threshold scan would confirm the spins.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 25
%

'
• Spin-independent cross-sections for the 13 benchmark points of
Battaglia et al. hep-ph/0106204 .
Ellis,Feng,Ferstl,KM,Olive hep-ph/0110225
$
• No lower limit: cancellations are possible.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 26
%

'
• Spin-dependent cross-sections for the 13 benchmark points of
Battaglia et al. hep-ph/0106204 .
Ellis,Feng,Ferstl,KM,Olive hep-ph/0110225
$
• Far below sensitivity of near-term future experiments.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 27
%

'
• As usual, spin-dependent and spin-independent cross-sections.
Cheng, Feng, KM, hep-ph/0207125
$
• The signals are enhanced near the s -channel resonance:
σ ∼ ( m q 1
− m
B 1
)
− 2
. Unnatural in SUSY, guaranteed here.
Cheng, Feng, KM, hep-ph/0207125
Servant, Tait, hep-ph/0209262
Majumdar, hep-ph/0209277
• Constructive interference: lower bound!
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 28
%

'
• Both the shape and the normalization of the background are uncertain:
• Hard positrons come from ˜
0
1
0
1
→ W W and ˜
0
1
χ
0
1
→ ZZ .
Ellis,Feng,Ferstl,KM,Olive hep-ph/0110225
$
• The signal is typically a small fraction of the background, and the shape is not very characteristic.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 29
%

'
• Annihilation into fermion pairs is not helicity suppressed.
B ( B
1
B
1
→ e
+ e
−
) = 20%
• There is a bump! The positrons are monoenergetic at birth.
Some smearing from propagation through the galaxy.
Cheng, Feng, KM, hep-ph/0207125
$
• AMS-II will be able to measure highp
T positrons!
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 30
%

' $
• LCWG: Connections to Astrophysics and Cosmology (2003)
• The charge:
• Assume the LHC has already “discovered” SUSY and performed the expected measurements of SUSY masses etc.
• How well can we predict the neutralino relic density based on the LHC results?
• How much do we benefit from the NLC?
• Our approach: (Birkedal,KM 2004)
• What are the relevant model parameters?
• How well can the LHC and NLC determine those?
• What is the expected uncertainty in Ω
DM h
2
?
• We necessarily have to choose a model (benchmark point) point B: m
0
= 57, M
1 / 2
= 250, A
0
= 0, tan β = 10, µ > 0.
• Typical for any benchmark set
• Similar points discussed in the LHC literature
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 31
%

'
• Point B: neutralinos annihilate through t -channel sfermion exchange. Need to measure squark, slepton masses.
• Squarks are heavy = ⇒ small effect on Ω h
2
• Right-handed sleptons are most important:
Birkedal,KM Preliminary
$
• M
˜
R
− M
˜ 0
1
= 15 GeV < 30 GeV. Unobservable at LHC?
• M
˜
L
> M
χ
0
2
= ⇒ `
˜
L will not be produced in cascades.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 32
%

'
• Constraining the irrelevant parameters is also important!
• The Higgs pole ˜
0
1
0
1
→ H
0
, A
0 appears at small m
A
.
Birkedal,KM Preliminary
$
• However, m
A
< 200 GeV would have been discovered...
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 33
%

'
• The size of µ determines the gaugino-higgsino mixing.
Birkedal,KM Preliminary
$
• How well can we trust the relic density codes?
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 34
%

'
• LHC: ˜
0
1
, ˜
0
2
, ˜
±
1
, ˜
L to within 10%.
Birkedal,KM Preliminary
$
• NLC: ˜
0
1
, ˜
0
2
, ˜
±
1
,
˜
L
,
˜
R to within 2%. Everything else above
250 GeV.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 35
%

'
• Can we eliminate the model dependence in the previous discussion? The usual approach:
• Choose a model (SUSY: N ∼ 120 parameters)
• Fix N − 2 of them (MSUGRA: m
0
− M
1 / 2 plane)
• Impose cosmological constraint = ⇒ parameter line.
• Predict collider signals
• The DM relic abundance is governed by the annihilation cross-sections for the reactions
χ + χ → X i
+
¯ i
, X i
= { q, `, g, W, Z, γ, h } .
• The inverse reaction takes place at colliders:
χ χ
χ
X i
=
⇒
X i
¯ i
¯ i
χ
• X i
= { µ, τ, ν, h, t, b } channels are challenging, the rest accessible at least in principle at LHC and NLC.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 36
$
%

'
• WIMPs are non-relativistic at freeze-out:
σ i
( χχ → X i
¯ i
) v =
∞
X
σ i
( J ) v
2 J
J =0
• The lowest non-vanishing partial wave ( J
0
) dominates:
σ an
≡
X
σ
( J
0
) i i
• What does cosmology tell us?
Birkedal, KM, Perelstein, hep-ph/0403004
$
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 37
%

' $
• WIMP annihilation and WIMP production at colliders are related by detailed balancing:
σ ( χ + χ → X i
+ ¯ i
)
σ ( X i
+ ¯ i
→ χ + χ )
= 2 v
2
X
(2 S
X
+ 1)
2 v 2
χ
(2 S
χ
+ 1) 2
• Annihilation fractions:
κ i
=
σ i
( J
0
)
σ an
,
X i
κ i
= 1 .
• Model-independent prediction of the WIMP production rate at an X i
X i collider:
1 / 2+ J
0
σ ( X i
¯ i
→ 2 χ ) = 2
2( J
0
− 1)
κ i
σ an
(2 S
χ
+ 1)
2
(2 S
X
+ 1) 2
1 −
4 M
2
χ s
• Known parameters: { σ an
, S
X
, s }
• Unknown parameters: { κ i
, M
χ
, S
χ
, J
0
}
• Applicable only close to 2 χ threshold ( v
χ
1).
• But... no trigerrable signature!
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 38
%

' $
• What to do?
• Give up model-independence, consider production of heavier particles (superpartners, KK-modes etc.)
• Tag the known initial state with a soft photon/gluon e
+ e −
χ
=
⇒ e
+
χ e −
χ
χ
γ
• Soft photon factorization: dσ ( e
+ e − → 2 χ + γ ) dE
γ d cos θ
=
2 α
π
1
E
γ
1 sin 2 θ
σ ( e
+ e
−
→ 2 χ )
• Applicable for E
γ
√ s − M
χ
.
• In specific models, we expect κ e
∼ 20% = ⇒ LC!
• Analogously, WIMP production at hadron colliders:
σ ( q ¯ → 2 χ + g ) ∼ α s
κ q
σ an
, σ ( gg → 2 χ + g ) ∼ α s
κ g
σ an
Very challenging experimentally...
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 39
%

'
• Compare the analytic formula to the exact result in specific models
• MSUGRA (bulk region)
• UED
Birkedal, KM, Perelstein, hep-ph/0403004
$
• At low v
χ
, soft factorization breaks down.
• At high v
χ
, higher-order terms in the velocity expansion become relevant.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 40
%

'
• Discovery reach of the NLC. Cuts:
• M
χ
= 0 .
87 E beam
( χ ’s non-relativistic)
• p
γ
T
> 0 .
03 E beam
(suppress Bhabha, ν ¯ remains)
• E
γ max
< 0 .
065 E beam
(soft factorization)
• No polarization.
Birkedal, KM, Perelstein, hep-ph/0403004
$
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 41
%

' $
• Recent new ideas in particle physics lead to novel alternatives for dark matter candidates. SUSY DM? Not so fast...
• Extra dimensions also yield natural dark matter candidates, with calculable rates for detection.
• Little Higgs theories, with certain assumptions, also have a dark matter candidate.
• The usual question: how do we discover these models?
• How do we tell the difference?
• How do we uncover the identity of the dark matter?
• How will we know we have found the dark matter at the LHC?
• WMAP implies model-independent, guaranteed and experimentally challenging rates for missing energy signals of
DM at colliders.
&
DM and Physics BSM at Colliders Konstantin Matchev, University of Florida - 42
%