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

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Dark Matter Direct Detection

15 GeV

5 GeV

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Observable

p p_ (p)

The transverse momentum (pT) is conserved.

The signal is missing transverse momentum (MET).

Cannot be detected!

Longitudinal

Transverse

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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, …

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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

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____________ 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

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Outline Motivation

From Mediator to Contact Interaction

Current Collider Constraints

LHC Reach

Summary

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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

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Tevatron + LHC

CMS arXiv:1102.2020

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Outline Motivation

From Mediator to Contact Interaction

Current Collider Constraint

LHC Reach

Summary

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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

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LHC Reach

Xenon 100MZ’=500 GeV gZ’=gD

MZ’=3000 GeV gZ’=gD

MZ’=500 GeV gD=1

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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

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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

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Determine the Mass of Z’

Bin[1]: 500 GeV < PT < 600 GeV;

Bin[2]: PT > 600 GeV.

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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.

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Backup: LEP constraint

Mono photon + MET

Di-lepton

B-xL model

gZ’ = gD

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Overview

Existence;

Dark;

Massive;

Stable;

Relic abundance

~ 25%;

Not identified yet.

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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