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Collider Constraints on Low Mass Dark Matter. Haipeng An University of Maryland. In collaboration with Xiangdong Ji and Liantao Wang. Outline. Motivation From Mediator to Contact Interaction Current Collider Constraint LHC Reach Summary. 15 GeV. 5 GeV. Dark Matter Direct Detection. - PowerPoint PPT Presentation
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5/9/2011 PHENO 2011 1
Collider Constraints on Low Mass Dark Matter
Haipeng AnUniversity of Maryland
In collaboration with Xiangdong Ji and Liantao Wang
5/9/2011 PHENO 2011 2
Outline Motivation
From Mediator to Contact Interaction
Current Collider Constraint
LHC Reach
Summary
5/9/2011 PHENO 2011 3
Dark Matter Direct Detection
15 GeV
5 GeV
5/9/2011 PHENO 2011 4
Observable
p p_ (p)
The transverse momentum (pT) is conserved.
The signal is missing transverse momentum (MET).
Cannot be detected!
Longitudinal
Transverse
5/9/2011 PHENO 2011 5
Relevant searches with MET Tevatron Constraints
LEP constraints
CDF Collaboration, PRL 101, 181602, 2008.
p p MET + Mono-jet
e+ e- MET + Mono-photon
L3 Collaboration, Phys. Lett. B 587, 16, 2004.
Yang Bai, Patrick Fox, Roni Harnik 1005.3797.Goodman, Ibe, Rajaraman, Shepherd, Tait, Yu 1005.1286, 1008.1783;
Patrick J. Fox, Roni Harnik, Joachim Kopp, Yuhsin Tsai 1103.0240
5/9/2011 PHENO 2011 6
Outline Motivation
From Mediator to Contact Interaction
Current Collider Constraint
LHC Reach
Summary
5/9/2011 PHENO 2011 7
Collider ConstraintsYang Bai, Patrick Fox, Roni Harnik 1005.3797.Goodman, Ibe, Rajaraman, Shepherd, Tait, Yu 1005.1286, 1008.1783;Patrick J. Fox, Roni Harnik, Joachim Kopp, Yuhsin Tsai 1103.0240Jean-Francois Fortin, Tim M.P. Tait 1103.3289
If the mass of the intermediate particle is around a few hundred GeV, the interaction cannot be described by a contact local operator.
Effective operator
Mediator: vector boson, scalar boson, …
Dark matter: spinor, scalar, …
Interaction: vector-like, dipole-like, …
5/9/2011 PHENO 2011 8
Z’ model
Z' Z'5 D D5 Z' Dg , g , g , g , M , M
μ μ μ μμ Z' Z'5 5 D D5 5L= Z' [q(g γ +g γ γ )q+ χ(g γ +g γ γ )χ].
1. Leptophobic vector boson (Z’) couples to SM quarks universally and dark matter particle.
2. Dark Matter particle is a Dirac spinor.
3. The coupling between Z’ and dark matter can be either vector-like.
2 2 2 2 2Z' D N D
SI 4 2Z' N D
3 g g M Mσ =
πM (M +M )
0 0
5/9/2011 PHENO 2011 9
____________ M D 50 G eV
____________ M D 150 G eV
- - - - - - - - - - M D 50 G eV Con tact In teract ion
- - - - - - - - - - M D 150 G eV Con tact In teract ion
0 2 0 0 4 0 0 6 0 0 8 0 0 1 0 0 0 1 2 0 0 1 4 0 0
0 .5
1 .0
1 .5
2 .0
M Z ' G eV
pb
From Mediator to Contact Interaction
gZ’=gD , gZ’/MZ’ = 400 GeV
MZ’ < 2MD , 3-body final state
χ
χ
Z'q
q_
g
ˆD Z'2M <M < s , 2-body
Z'
q
q_
g χ
χ
Contact interaction
p p MET + Mono-jet
Width
5/9/2011 PHENO 2011 10
Outline Motivation
From Mediator to Contact Interaction
Current Collider Constraints
LHC Reach
Summary
5/9/2011 PHENO 2011 11
Tevatron Constraint
Xenon100 11 days
New Xenon100
CoGeNT
No axial couplings;
gZ’=gD;
gZ’5=0;
gD5=0.
Collid
er
con
str
ain
t is
str
on
ger
than
dir
ect
dete
cti
on
.
MZ’=100 GeV
MZ’=300 GeV
MZ’=700 GeV
MZ’=1500 GeV
CalcHEP2.5.7
5/9/2011 PHENO 2011 12
Tevatron + LHC
CMS arXiv:1102.2020
5/9/2011 PHENO 2011 13
Outline Motivation
From Mediator to Contact Interaction
Current Collider Constraint
LHC Reach
Summary
5/9/2011 PHENO 2011 14
LHC Reach
S > 5 B
p p Missing ET + Monojet
Missing ET > 500 GeV, 100 fb-1 luminosity.Vacavant and Hinchliffe, J. Phys. G 27 (2001) 1839-1850
SM background ≈ 20000.Shepherd, Tait, Yu 1005.1286, 1008.1783
5/9/2011 PHENO 2011 15
LHC Reach
Xenon 100MZ’=500 GeV gZ’=gD
MZ’=3000 GeV gZ’=gD
MZ’=500 GeV gD=1
5/9/2011 PHENO 2011 16
LHC Reach
0 5 0 0 1 0 0 0 1 5 0 0 2 0 0 0 2 5 0 01 0 4 2
1 0 4 1
1 0 4 0
1 0 3 9
1 0 3 8
M Z ' G e V
SI
cm2 MD = 20 GeV
MD = 5 GeV
MD = 1 GeVZ’ on shell
Z’ off shell
5/9/2011 PHENO 2011 17
Determine the Mass of Z’
6 0 0 8 0 0 1 0 0 0 1 2 0 0 1 4 0 0 1 6 0 0 1 8 0 0 2 0 0 01 0 4
0 .0 0 1
0 .0 1
0 .1
1
J e tP T G e V Nor
mal
ized
Num
ber
ofEv
ents
SM background
300 GeV500 GeV
700 GeV1100 GeV
1500 GeV
2000 GeV
Vacavant and Hinchliffe,
J. Phys. G 27 (2001) 1839
5/9/2011 PHENO 2011 18
Determine the Mass of Z’
Bin[1]: 500 GeV < PT < 600 GeV;
Bin[2]: PT > 600 GeV.
5/9/2011 PHENO 2011 19
Summary Collider constraints are very important in the
case of low mass dark matter;
Tevatron constraints and LHC reach strongly depends on the mass of Z’;
The mass of Z’ can be determined from the distribution of jet transverse momentum.
5/9/2011 PHENO 2011 20
Backup: LEP constraint
Mono photon + MET
Di-lepton
B-xL model
gZ’ = gD
5/9/2011 PHENO 2011 21
Overview
Existence;
Dark;
Massive;
Stable;
Relic abundance
~ 25%;
Not identified yet.
5/9/2011 PHENO 2011 22
Tevatron Constraints on Direct Detection Cross section
gZ’5 = 0, gD = 0, MD = 5 GeV.
gD5 = 1g
D5 = 0.5
V2 ~ 10-6 SIMD
CalcHEP2.5.6