search for dark matter mediators - institut national de

Raffaele Gerosa22/03/17 1

Search for Dark Matter Mediators

Speaker : Raffaele Gerosa1

1University of California San Diego (UCSD)

Rencontres de Moriond EW, 23th March 2017 (La Thuile)

On behalf of CMS and ATLAS Collaborations


Introduction

• Cosmological observations support that 85% of the matter component of the universe is dark matter (DM)

Key Properties

Non baryonic, long-lived, massive i.e gravitationally interacting, dark (no color and no electric charge)

• The hunt of Dark Matter particles is an interdisciplinary effort

From cosmology to particle physics

Potentially accessible by a number of different experiments

Potentially accessible by precision measurements of the SM


Dark Matter detection

Detection of DM implies its interaction with known matter

DM

SM

DM

SM

Direct Detection

DM-nucleon scattering

Indirect Detection

DM annihilation

Collider experimentsProduction of DM

DM

DM

SM

SM

SM

SM

DM

DM


Simplified DM models for collider searches

• Several BSM models provides DM candidates: SUSY, ADD, little Higgs

• Alternative approach: use simple models to catch the underlying physics

s-channel simplified DM models → DMWG @ LHC

• Include a mediator (mMED) coupled to SM quarks and DM

• 4 basic currents: Vector or Axial-Vector, Scalar or Pseudo-scalar

• DM candidate assumed to be a Dirac fermion with mass (mDM)

• Coupling between mediator and SM (DM) particles are free parameters gSM (gDM)

arXiv:1507.00966

Mono-X searches

• Experimentally, to detect DM, it needs to recoil against some other objects

• X = quark/gluon, photon, W/Z ..

• High pT object balancing large ETmissSpin-1 V/AV

https://arxiv.org/pdf/1507.00966.pdf

Raffaele Gerosa22/03/17

Even

ts /

50 G

eV

2<10

1<10

1

10

210

310

410

510

610

710 ATLAS-1 = 13 TeV, 3.2 fbs

Signal Region>250 GeV miss

T>250 GeV, E

Tp

Data 2015Standard Model

) + jetsii AZ() + jetsio AW() + jetsiµ AW() + jetsi eAW(

ll) + jetsAZ(Dibosons

+ single toptt) = (350, 345) GeV0

r¾, b~m()= (150, 1000) GeV

med, M

DM(m

=5600 GeVD

ADD, n=3, M

[GeV]missTE

400 600 800 1000 1200 1400

Dat

a / S

M

0.5

1

1.5

5

Direct DM searches at colliders• The mono-X search which provides the strongest limits on spin-1 mediators is the mono-jet analysis

Signature

• Search for DM mediator produced in association with a high pT jet

• Select events with ETmiss > 200 GeV

• Jets and ETmiss balanced in the transverse plane

Background estimation

• Main backgrounds are Zvv and W+jets

• Modelled from control regions in data

Interpretation

• 95% C.L. exclusion limit on the signal strength µ = σ/σth

• Exclusion sensitivity vs mMED and mDM for fixed coupling values

(gSM = gq = 0.25, gDM = 1)

PRD 94 (2016) 032005 arXiv:1703.01651

• Major challenge consists in estimate backgrounds

https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2015-03/

https://arxiv.org/abs/1703.01651


Even

ts /

50 G

eV

2<10

1<10

1

10

210

310

410

510

610

710 ATLAS-1 = 13 TeV, 3.2 fbs


T>250 GeV, E

Tp





r¾, b~m()= (150, 1000) GeV

med, M

DM(m

=5600 GeVD

ADD, n=3, M

[GeV]missTE

400 600 800 1000 1200 1400

Dat

a / S

M

0.5

1

1.5

5


Signature







Interpretation



(gSM = gq = 0.25, gDM = 1)

PRD 94 (2016) 032005 arXiv:1703.01651


Are these the only searches constraining DM at colliders?




Even

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50 G

eV

2<10

1<10

1

10

210

310

410

510

610

710 ATLAS-1 = 13 TeV, 3.2 fbs


T>250 GeV, E

Tp





r¾, b~m()= (150, 1000) GeV

med, M

DM(m

=5600 GeVD

ADD, n=3, M

[GeV]missTE

400 600 800 1000 1200 1400

Dat

a / S

M

0.5

1

1.5

5


Signature







Interpretation



(gSM = gq = 0.25, gDM = 1)

PRD 94 (2016) 032005 arXiv:1703.01651


Constraints on Dark-Matter spin-1 mediators come from resonance searches

Are these the only searches constraining DM at colliders?




Dijet search

• Search for heavy resonances decaying to qq, qg or gg final states

[pb/

TeV]

jj/d

mσd

(13 TeV)-136 fbCMSPreliminary Data

Fitgg (2.0 TeV)qg (4.0 TeV)qq (6.0 TeV)

/ ndf = 38.9 / 39 = 1.02χWide PF-jets

> 1.25 TeVjjm| < 1.3η∆| < 2.5, |η|

410

310

210

10

1

1−10

2−103−10

4−10

Dijet mass [TeV]

Unc

erta

inty

(Dat

a-Fi

t)

3−2−1−0123

2 3 4 5 6 7 8

6

• Lower limit in the mass reach due to trigger limitations

Require at leat two jets, one with high pT

Require small rapidity separation between the two jets

• Fit the smooth background spectrum

• Look for local excesses along the di-jet mass spectrum

ATLAS-EXOT-2016-21

CMS-EXO-16-056

• Selections:

Reconstruct the invariant mass mjj

• Mass reach is extended down to ~500 GeV with trigger based analysis (data scouting) → otherwise only mX > 1 TeV

ATLAS-CONF-2016-030

[TeV]jjReconstructed m2 3 4 5 6 7 8 9

Even

ts /

Bin

1−10

1

10

210

310

410

510

610

710

|y*| < 0.6Fit Range: 1.1 - 8.2 TeV

-value = 0.63p 3× σ*, q

[TeV]jjm2 3 4 5 6 7 8 9

Sign

ifica

nce

2−02

[TeV]jjm2 3 4 5 6 7 8 9

MC

Dat

a-M

C

0.5−0

0.5 JES Uncertainty

ATLAS Preliminary-1=13 TeV, 37.0 fbs

DataBackground fitBumpHunter interval

= 4.0 TeV*q

*, mq = 5.0 TeV

*q*, mq

https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/CONFNOTES/ATLAS-CONF-2016-030/


[TeV]Z’m1.5 2 2.5 3 3.5

qg

0.05

0.1

0.15

0.2

0.25

0.3-1 = 13 TeV, 37.0 fbs

PreliminaryATLAS

Observed limitExpected limit

Dijet result: Z’ leptophobic

• Exclusion limits are usually expressed in σ x BR x acceptance• Assumptions on the lineshape play a fundamental role → Narrow width approximation → ΓX << σexp

Model dependent result for a leptophobic Z’

• The coupling gq affects the production cross section through the total width

• Sensitivity to small gq limited by small cross section

• For gq > [0.5,0.6] → narrow width approximation not valid anymore

7

Upper bound on gq ranges from [0.08,0.35] in the range

mZ’ [0.6,3.5] TeV

Cross section limit for quark-quark resonances

Resonance mass [TeV]

[pb]

Α × Β ×

σ

5−10

4−10

3−10

2−10

1−101

10

210

310

410

510 CMS Preliminary (13 TeV)-1 & 36 fb-127 fb

quark-quark95% CL limits

Observed 1 s.d.±Expected 2 s.d.±Expected

Axiguon/coloron Scalar diquarkW'Z'DM mediator

1 2 3 4 5 6 7 8 9

←→Low

massHighmass

CMS-EXO-16-056

ATLAS-EXOT-2016-21


ATLAS low mass dijet

• Goal: extend the dijet search to lower masses → mX < 500 GeV

• Strategy: resonance produced in association with a high pT ISR jet or photon

[TeV]jjReconstructed m210×2 210×3 210×4 310

Even

ts

210

310

410

510

> 150 GeV)γT,

(PγX + *| < 0.8

12|y

50 × σ = 350 GeV, Z'

= 0.30), mqZ' (g-value = 0.67p

Fit Range: 169 - 1493 GeV

[GeV]jjm200 300 400 500 1000Si

gnifi

canc

e

2−02


DataBackground fitBumpHunter interval

[GeV]Z'm200 300 400 500 600 700 800 900

qg

0.050.1

0.150.2

0.250.3

0.350.4

0.450.5

0.55

>150 GeV)γT,

(PγX + -1 = 13 TeV, 15.5 fbs

PreliminaryATLASobs. limitexp. limit

[GeV]Z'm300 350 400 450 500 550 600

qg

0.050.1

0.150.2

0.250.3

0.350.4

0.450.5

0.55

>430 GeV)T,j

X + j (P-1 = 13 TeV, 15.5 fbs

PreliminaryATLASobs. limitexp. limit

8

Resonance + γ: photon ET > 150 GeV, two jets with |y*| < 0.8

q

q q

q

X

γ

q

q q

q

g

X

Resonance + j: one jet pT > 430 GeV, two additional jets with |y*| < 0.6

ATLAS-CONF-2016-070

Z’ model interpretation

Resonance+γ

Resonance+j

X+j becomes inefficient for mX < 350 GeV cause jets from the resonance becomes close to each other and overlaps in the detector



CMS boosted low mass dijet

50 100 150 200 250 300

N e

vent

s

0

200

400

600

800

1000

1200dataQCD Pred.Total SM Pred.W(qq)Z(qq)

= 1B

Z'(qq), g

CMS Preliminary (13 TeV)-12.7 fb

soft drop mass (GeV)50 100 150 200 250 300 D

ata/

Pred

ictio

n

0.50.60.70.80.911.11.21.31.41.5

Z' mass (GeV)80 100 200 300 400 500

Bco

uplin

g, g

00.5

11.5

22.5

33.5

44.5

5CMSPreliminary (13 TeV)-12.7 fb

expectedobserved

σexpected 2σexpected 1

UA2CDF Run 1CDF Run 2

-1 20.3 fb⊕ATLAS 13 )γ (ISR -1 3.2 fb⊕ATLAS 13

(TLA)-1 3.2 fb⊕ATLAS 13 (Scouting)-1 18.8 fb⊕CMS 8

9

• Strategy: look for a boosted low mass resonance (mX < 300 GeV) produced in association with an ISR jets

• Selections: one large cone (AK8) jet (pT > 500 GeV) which collect the decay products of the resonancejet substructures are used to suppress QCD-multijet backgrounds and to reconstruct the resonance invariant mass

• Signal extraction: fit to the large cone soft-drop mass (mSD) spectrum

CMS-EXO-16-030

Z’ leptophobic

model

ATLASCMS

http://cms-results.web.cern.ch/cms-results/public-results/preliminary-results/EXO-16-030/


DM interpretation of resonance searches

• DM simplified model for spin-1 mediator is equivalent to the leptophobic Z’ explored in dijet searches• Difference: the addition of a DM candidate modifies the total width of the mediator

Monojet production

Dijet production

10

Z’

Z’

Mediator Width Interesting scenarios

mMED >> mDM: the relative branch fraction of monojet and dijet is proportional to NcNq gSM2/gDM2

gSM << gDM, gDM ~ 1: narrow resonance but BR monojet larger than dijet one

gDM >> gSM, gDM > 1: resonance not narrow anymore BR monojet larger than dijet one

2mDM >> mMED: no partial width into dark matter so the Z’ model reduces to the standard one used in dijet searches


DM interpretation of resonance searches

• DM simplified model for spin-1 mediator is equivalent to the leptophobic Z’ explored in dijet searches• Difference: the addition of a DM candidate modifies the total width of the mediator

Monojet production

Dijet production

10

Z’

Z’

Mediator Width Interesting scenarios

mMED >> mDM: the relative branch fraction of monojet and dijet is proportional to NcNq gSM2/gDM2

gSM << gDM, gDM ~ 1: narrow resonance but BR monojet larger than dijet one

gDM >> gSM, gDM > 1: resonance not narrow anymore BR monojet larger than dijet one

2mDM >> mMED: no partial width into dark matter so the Z’ model reduces to the standard one used in dijet searchesThe exclusion power of th

e reinterpretation of resonance searches

into DM limits stric

tly depends on the (gSM,gDM) values


Mediator mass [GeV]0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

[GeV

]D

Mm

0

200

400

600

800

1000

1200

1400

1600

CMS 95% CL[EXO-16-056]Dijet

[EXO-16-030]Boosted dijet

[EXO-16-037]qq

DM + j/V

[EXO-16-039]γDM +

[EXO-16-038]llDM + Z

[EXO-16-040]DM + t (100% FC)

DM

= 2 x m

MedM

0.12≥ 2

hcΩ

= 1.0DM

g = 0.25qg

Dirac DM

CMS 95% CL[EXO-16-056]Dijet

[EXO-16-030]Boosted dijet

[EXO-16-037]qq

DM + j/V

[EXO-16-039]γDM +

[EXO-16-038]llDM + Z

[EXO-16-040]DM + t (100% FC)

Axial-Vector mediator

Preliminary CMS (13 TeV)-1 & 36 fb-1, 27 fb-113 fb

0.12≥ 2

hcΩ

[EXO-16-056] Dijet

[EXO-16-030] Boosted Dijet

[EXO-16-037] qqDM + j/V

[EXO-16-039] γDM +

[EXO-16-038] llDM + Z

Z' mass [GeV]500 1000 1500 2000 2500 3000 3500

' qgC

oupl

ing

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45CMS Preliminary

(13 TeV)-1 & 36 fb-127 fb

95% CL upper limits

/ 2Med > MDMm

= 0DMm

ObservedExpected 1 std. deviation±

2 std. deviation±

←→Lowmass

Highmass

CMS: direct vs indirect DM searches

Z' mass (GeV)80 100 200 300 400 500

Bco

uplin

g, g

00.5

11.5

22.5

33.5

44.5

5CMSPreliminary (13 TeV)-12.7 fb

expectedobserved

σexpected 2σexpected 1

UA2CDF Run 1CDF Run 2

-1 20.3 fb⊕ATLAS 13 )γ (ISR -1 3.2 fb⊕ATLAS 13

(TLA)-1 3.2 fb⊕ATLAS 13 (Scouting)-1 18.8 fb⊕CMS 8

11

CMS Z’→ dijet searches DM Interpretation

Benchmark: Axial-Vector mediator with gq = gSM = 0.25 and gDM = 1

Comparison between mono-X DM searches and dijet boundsGiven the coupling choice → dijet bounds are much

stronger than mono-X ones in the on-shell region

CMS-EXO-16-056


ATLAS: direct vs indirect DM searches

Mediator Mass [TeV]

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

DM

Ma

ss [

Te

V]

0.2

0.4

0.6

0.8

1

1.2

DM Simplified Model Exclusions August 2016PreliminaryATLAS

= 1.5DM

= 0.1, gq

g

Axial-vector mediator, Dirac DM

Perturb

ative unita

rity

DM Mass = Mediator Mass

×2

= 0.122

hcΩ

Thermal relic

= 0.122

hcΩ

Thermal relic

AT

LA

S-C

ON

F-2

016-0

30

Dije

t T

LA

Phys

. R

ev.

D. 91 0

52007 (

2015)

Dije

t 8

Te

V

arXiv:1604.07773

+jetmissTE

JHEP 06 (2016) 059

γ+missTE

As gSM gets weaker compared to gDM → dijet constraints becomes complementary to mono-XFor “relatively large” quark coupling (gSM) → dijet constraints are very strong

Constraining power in the off-shell region remains strong

12

Mediator Mass [TeV]

0 0.5 1 1.5 2 2.5

DM

Ma

ss [

Te

V]

0.2

0.4

0.6

0.8

1

1.2


= 1DM

= 0.25, gq

g


Per

turb

ativ

e un

itarit

y

DM M

ass = M

ediator Mass

×2

= 0.122

hcΩ

Thermal re

lic

= 0.122

hcΩ

Thermal re

lic

< 0

.12

2 h c

Ω

AT

LA

S-C

ON

F-2

016-0

30

Dije

t T

LA

Phys

. R

ev.

D. 91 0

52007 (

2015)

Dije

t 8

Te

V

AT

LA

S-C

ON

F-2

016-0

69

Dije

t

arXiv:1604.07773

+jetmissTE

JHEP 06 (2016) 059

γ+missTE

AT

LA

S-C

ON

F-2

016-0

70

Dije

t+IS

R

gSM = 0.25, gDM = 1 gSM = 0.10, gDM = 1.5


What about spin-0 DM mediators??

13


Searches for a spin-0 mediator

• Strongest limits for spin-0 mediators comes from mono-jet and ttbar + DM

• No limits / interpretations from high mass resonance searchesg

g

t

t t

t

g

q0

q

q0

W, Z

q

W±, Z

q

q0

q0

W/ZW/Z

q

g

g

tt

tt

'/a

g

g

t

t

1

14

mono-jet

ttbar + DM

• Coupling choice gSM = gDM = 1

• Dark matter mass fixed to be mDM = 1 GeV

• mono-X searches have exclusion sensitivity for low mass S/PS mediators

• ttbar + DM is the most sensitive search for low mass scalarsCMS-EXO-16-006 arXiv:1703.01651

http://cds.cern.ch/record/2204933?ln=en



Higgs boson as portal to DM

WIMP mass [GeV]1 10 210 310

]2W

IMP-

nucl

eon

cros

s se

ctio

n [c

m

57 10

55 10

53 10

51 10

49 10

47 10

45 10

43 10

41 10

39 10

DAMA/LIBRA (99.7% CL)CRESST II (95% CL)CDMS SI (95% CL)CoGeNT (99% CL)CRESST II (90% CL)SuperCDMS (90% CL)XENON100 (90% CL)LUX (90% CL)

Scalar WIMPMajorana WIMPVector WIMP

ATLAS

Higgs portal model:ATLAS 90% CL in

-1 = 7 TeV, 4.5-4.7 fbs-1 = 8 TeV, 20.3 fbs

Vis. & inv. Higgs boson decay channels]inv, BR Z , , g , , , b , t , Z , W [

<0.22 at 90% CLinv

assumption: BRW,Z No

invBR0.2 0.1 0 0.1 0.2 0.3 0.4 0.5

-2

ln

0

2

4

6

8

10ATLAS

-1 = 7 TeV, 4.5-4.7 fbs-1 = 8 TeV, 20.3 fbs

Obs.:Vis. & inv. decay channels

Inv. decay channels

Vis. decay channels

• Another place for DM → SM Higgs branching ratio since it couples to everything with mass

• Higgs invisible searches set an upper limit on BR(Hinv) to be < ~25%

Collider limits are the most stringent ones for low mDM

(arXiv:1112.3299)Higgs portal model

Hidden sector provides DM particle coupled to SM Higgs boson

BR limits are converted into bounds on DM-nucleon cross section

Low mDM is a region hard to be explored by direct detection experiment

JHEP11(2015)206

15


http://link.springer.com/article/10.1007/JHEP11(2015)206


Conclusion

• Impressive amount of DM searches at colliders:

Large number of signatures have been explored in ETmiss + X searches

Bounds on dark matter mediators comes also from re-cast of resonance searches

For gq = 0.25 and gDM = 1 → dijet search excludes spin-1 mediators with a mass up 2.5-3 TeV

• LHC provides complementary results to direct and indirect detection experiments

Results can be compared with direct and indirect detection experiments in terms of DM-nucleon cross section

Unfortunately no sign of Dark-Matter from collider searches so far

Nevertheless …. the hunt of dark matter continues

Colliders provide the strongest bounds for the spin-dependent DM-nucleon cross section

Colliders provide the strongest bounds for the spin-independent DM-nucleon cross section for mDM < 10 GeV


Backup

17


Direct Detection Experiments

Look for elastic scattering of DM against nucleonsDetector deep underground to minimise backgrounds

LUX experiment

Experiments: LUX, PandaX ..etc

DM

SM

DM

SM

Direct Detection

DM-nucleon scattering


Indirect Detection Experiments

DM pairs annihilate in galaxy / stars into SM particles

Annihilation happens in region of high density of DM

Experiments: ice-cube, super KK, PICO-2L ..etc

ice-cubeDM

DM

SM

SM

Indirect Detection

DM annihilation

19


Collider Experiments

Hadron Colliders

Production of DM in high energy particle collisions DM leave the detector w/o release energy

DM may be observed as missing transverse energy

LHCSM

SM

DM

DM

Collider experiments

Production of DM


CMS dijet results


[pb]

Α × Β ×

σ

5−10

4−10

3−10

2−10

1−101

10

210

310

410


quark-quark95% CL limits


Axiguon/coloron Scalar diquarkW'Z'DM mediator

1 2 3 4 5 6 7 8 9

←→Low

massHighmass

Resonance mass [TeV] [p

b]Α ×

Β × σ

5−10

4−10

3−10

2−10

1−101

10

210

310

410


quark-gluon95% CL limits


String

Excited quark

1 2 3 4 5 6 7 8 9

←→Low

massHighmass


[pb]

Α × Β ×

σ

5−10

4−10

3−10

2−10

1−101

10

210

310

410


gluon-gluon95% CL limits


= 1/2) 2sColor-octet scalar (k

1 2 3 4 5 6 7 8 9

←→Low

massHighmass


[pb]

Α × Β ×

σ

5−10

4−10

3−10

2−10

1−101

10

210

310

410


95% CL limitsgluon-gluonquark-gluonquark-quark

StringExcited quarkAxiguon/coloron Scalar diquark

= 1/2) 2sColor-octet scalar (k

W'Z'DM mediatorRS graviton

1 2 3 4 5 6 7 8 9

←→Low

massHighmass

Cross section upper limit mainly depends on the partonic decay state

which affects the lineshape model

21


ATLAS dijet results

[TeV]*qm2 4 6

BR

[pb]

× A × σ

4−10

3−10

2−10

1−10

1ATLAS Preliminary

*qObserved 95% CL upper limitExpected 95% CL upper limit

σ 2 ± and σ 1 ±Expected

-1=13 TeV, 37.0 fbs|y*| < 0.6

[TeV]thM4 6 8 10

[pb]

A × σ

5−10

4−10

3−10

2−10

1−10ATLAS Preliminary

QBHObserved 95% CL upper limitExpected 95% CL upper limit


-1=13 TeV, 37.0 fbs|y*| < 0.6

[TeV]W*m2 3 4 5

BR

[pb]

× A × σ

3−10

2−10

1−10

1 ATLAS Preliminary

)=0)xφW*(sin(Observed 95% CL upper limitExpected 95% CL upper limit


-1=13 TeV, 37.0 fbs|y*| < 1.2

[TeV]W'm2 4 6

BR

[pb]

× A × σ

4−10

3−10

2−10

1−10

1ATLAS Preliminary

W'Observed 95% CL upper limitExpected 95% CL upper limit


-1=13 TeV, 37.0 fbs|y*| < 0.6

Benchmark models

• Excited quarks

• Extra gauge bosons W’, Z’ and W*

• QBH: RS Graviton and ADD

• Model dependent limit cause assume a specific lineshape according to the model

22


ATLAS dijet resultsAcceptance for Z’ vs gq

[TeV]Gm2 4 6

BR

[pb]

× A × σ

4−10

3−10

2−10

1−10

1


|y*| < 0.6

= 0G/mGσExp. 95% CL upper limit for σ 2 ± and σ 1 ±Expected

Obs. 95% CL upper limit for: = 0.15G/mGσ

= 0.10G/mGσ

= 0.07G/mGσ

= 0.03G/mGσ

= 0G/mGσ

Model independent limit

Gaussian core lineshape assumed

95% upper limits for vs intrinsic width


Trigger level analysisEvents

510

610

710

|y*| < 0.6Fit Range: 443 - 1236 GeVp-value = 0.44

[GeV]jjm500 600 700 800 900 1000Si

gnificance

−202

-1s=13 TeV, 3.4 fbDataBackground fitBumpHunter interval

ATLAS Preliminary

600 800 1000 1200 1400 1600 1800 2000

[pb/

TeV]

jj/d

mσd

(13 TeV)-127 fbCMSPreliminary Data

Fitgg (0.75 TeV)qg (1.20 TeV)qq (1.60 TeV)

/ ndf = 20.3 / 20 = 1.02χWide Calo-jets

< 2.04 TeVjj0.49 < m| < 1.3η∆| < 2.5, |η|

610

510

410

310

210

10

1

1−10

Dijet mass [TeV]

Unc

erta

inty

(Dat

a-Fi

t)

3−2−1−0123

0.6 0.8 1 1.2 1.4 1.6 1.8 2

• Goal: have access to a lower mass range performing a trigger object based analysisLower thresholds on leading/subleading jets as well as jet-HT → increase the trigger rate

Reduce the event content to fit in the bandwidth budget → store and perform analysis on trigger objects

ATLAS-CONF-2016-030 • Selections:

L1 jet with ET > 75 GeV

Two jets at HLT with pT > 85 GeV, |η| < 2.8

Offline: pT > 185 GeV |y*| < 0.6

y* selection helps in having a better turn-on

Smooth background with analytical function

Analysis performed on calo-jets @ HLT

Trigger: HT > 250 GeV (pT jet > 40 GeV)

mjj [450,1.6] TeV, |Δηjj| < 1.3



ATLAS TLA analysis

[TeV]Gm0.4 0.6 0.8 1

BR

[pb]

× A × σ

1−10

1

10

210

ATLAS Preliminary

-1=13 TeV, 3.4 fbs|y*| < 0.3 = 0.10G/mGσ = 0.07G/mGσ = Res.G/mGσ

[TeV]Gm0.6 0.8 1

BR

[pb]

× A × σ

1−10

1

10

210

ATLAS Preliminary

-1=13 TeV, 3.4 fbs|y*| < 0.6 = 0.10G/mGσ = 0.07G/mGσ = Res.G/mGσ

Model independent limit for narrow gaussian resonances

ATLAS-CONF-2016-030

ATLAS-CONF-2016-030

Coupling exclusion for Z’ leptphobic

25




ATLAS: direct vs indirect DM searches

[GeV]Z’

m

300 400 1000 2000 3000

qg

0.05

0.1

0.15

0.2

0.25

0.3

0.35-1 = 13 TeV; 3.4-15.7 fbs

PreliminaryATLASATLAS-CONF-2016-030Low-mass dijet (TLA)

ATLAS-CONF-2016-069High-mass dijet

ATLAS-CONF-2016-070)γDijet+ISR (

ATLAS-CONF-2016-070Dijet+ISR (jet)| < 0.8

12|y*

| < 0.623

|y*

| < 0.312

|y* | < 0.612

|y*

| < 0.612

|y*

Expected limitObserved limit

Summary of Z’→ dijet ATLAS searches

Mediator Mass [TeV]

0 0.5 1 1.5 2 2.5

DM

Ma

ss [

Te

V]

0.2

0.4

0.6

0.8

1

1.2


= 1DM

= 0.25, gq

g


Per

turb

ativ

e un

itarit

y

DM M

ass = M

ediator Mass

×2

= 0.122

hcΩ

Thermal re

lic

= 0.122

hcΩ

Thermal re

lic

< 0

.12

2 h c

Ω

AT

LA

S-C

ON

F-2

016-0

30

Dije

t T

LA

Phys

. R

ev.

D. 91

0520

07 (

201

5)

Dije

t 8

Te

V

AT

LA

S-C

ON

F-2

016-0

69

Dije

t

arXiv:1604.07773

+jetmissTE

JHEP 06 (2016) 059

γ+missTE

AT

LA

S-C

ON

F-2

016-0

70

Dije

t+IS

RDM Interpretation

Comparison between direct DM searches in ETmiss+jet and ETmiss+γ and dijet bounds

Benchmark: Axial-Vector mediator with gq = gSM = 0.25 and gDM = 1

Given the coupling choice→ dijet bounds are much stronger than direct ones in the on-shell region

26


monojet ATLAS

[GeV]Am0 500 1000 1500 2000

[GeV

]r

m

0

200

400

)expm 1 ±Expected limit (

)PDF, scaletheorym 1 ±Observed limit (

Perturbativity Limit

Relic Density

ATLAS -1 = 13 TeV, 3.2 fbs

Axial Vector MediatorDirac Fermion DM

= 1.0r

= 0.25, gqg95% CL limits

r

= 2

mAm

[GeV]rm1 10 210 310 410

]2-p

roto

n) [c

mr (

SDm

42<10

39<10

36<10

33<10

30<10XENON100LUXPICO-2LPICO-60Axial Vector Mediator

90% CL limits

Dirac Fermion DM = 1.0

r = 0.25, gqg


27


monojet ATLAS

[GeV]rm1 10 210 310 410

]2-p

roto

n) [c

mr (

SDm

42<10

39<10

36<10

33<10

30<10XENON100LUXPICO-2LPICO-60Axial Vector Mediator

90% CL limits


r = 0.25, gqg


[GeV]rm1 10 210 310 410

]2-n

eutro

n) [c

mr (

SDm

43<10

41<10

39<10

37<10

35<10

33<10LUXAxial Vector Mediator

90% CL limits


r = 0.25, gqg


28


monojet CMS

Even

ts /

GeV

2−10

1−10

1

10

210

310

410

510 Data

)+jetsννZ(

)+jetsνW(l

WW/ZZ/WZ

Top quark

+jetsγZ(ll)+jets,

QCD

= 125 GeVH

Higgs Invisible, m

= 1.6 TeVmedAxial-vector, m

(13 TeV)-112.9 fb

CMSmonojet

Dat

a / P

red.

0.5

1

1.5

[GeV]missTE

200 400 600 800 1000 1200

pred

σ(D

ata-

Pred

.)

2−02

Even

ts /

GeV

2−10

1−10

1

10

210

310

41012.9 fb-1 (13 TeV)

CMSmono-V

Data

)+jetsννZ(

)+jetsνW(l

WW/WZ/ZZ

Top quark

+jetsγ(ll), γZ/

QCD

= 125 GeVH

Higgs invisible, m

= 1.6 TeVmedAxial-vector, m

Dat

a / P

red.

0.5

1

1.5

[GeV]missTE

300 400 500 600 700 800 900 1000

pred

σ(D

ata-

Pred

.)

2−02

29


monojet CMS

30


monojet CMS

31


Scalar and PseudoScalar DD limits

[GeV]DMm10 210

/s)

3 v

> (c

mσ

<

30−10

29−10

28−10

27−10

26−10

25−10

24−10

CMS obs. 90% CL

FermiLAT

(13 TeV)-112.9 fb

CMS = 1

DM = 1, g

qPseudoscalar med, Dirac DM, g

[GeV]DMm1 10 210 310

]2 [c

mD

M-n

ucle

onSIσ

46−10

45−10

44−10

43−10

42−10

41−10

40−10

39−10

38−10

37−10

36−10

35−10

34−10

CMS obs. 90% CLLUXCDMSLitePandaX-IICRESST-II

(13 TeV)-112.9 fb

CMS = 1

DM = 1, g

qScalar med, Dirac DM, g

• Collider results are compared to direct detection experiments as 90% CL upper limits on DM-nucleon cross section

• Exclusion in (mMED,mDM) translated into spin-independent / spin-dependent cross section via (arXiv:1407.8257)

Vector/Scalar interaction

Axial/Pseudo-scalar

Collider searches provides strongest limits for spin-independent

DM-nucleon cross section for low DM masses, i.e. < 10 GeV

Collider searches provides strongest limits for

annihilation cross section from Fermi-LAT

arXiv:1703.01651




monojet CMS: DD limits

33


CMS ttbar+DM

[GeV]MEDM10 210

0σ/

σup

per l

imit

on

1

10

210 Median expected 95% CL

σ 1±Expected

σ 2±Expected

Observed

(13 TeV)-12.2 fb=1 GeV

DM=1, m

DM=1, g

qScalar, Dirac, g CMS

Preliminary

[GeV]MEDM10 210

0σ/

σup

per l

imit

on

1

10

210 Median expected 95% CL

σ 1±Expected

σ 2±Expected

Observed

(13 TeV)-12.2 fb=1 GeVDM=1, m

DM=1, g

qPseudoscalar, Dirac, g CMS

Preliminary

[GeV]TmissE

Even

ts /

40 [G

eV]

5

10

15

20

25

Data QCD ll→Z νν→ZSingle Top ttV VV W + Jets(1l)tt (2l)tt

(x20) 100 GeVφM 1 GeV,χ

ps: M

(13 TeV)-12.2 fb

CMSPreliminary

[GeV]TmissE

200 250 300 350 400 450

MC

Dat

a

0.5

1

1.5

[GeV]missTE

200 300 400

Even

ts /

20 G

eV

10

20

30

40

50

60

70

80 Data(2l)tt(1l)tt

W + JetsVVVtt

Single Topνν→Z

ll→ZQCDpseudoscalar:

(13 TeV)-12.2 fb

CMSPreliminary

=1 GeVDM

=100 GeV, mMEDm (x20)

[GeV]missTE

200 250 300 350 400 450Dat

a / B

kg

0.5

1.0

1.5

[GeV]TmissE

Even

ts /

20 [G

eV]

20

40

60

80

100

120

140

160

180 Data QCD ll→Z νν→ZSingle Top ttV VV W + Jets(1l)tt (2l)tt

(x20) 100 GeVφM 1 GeV,χ

ps: M

(13 TeV)-12.2 fb

CMSPreliminary

[GeV]TmissE

200 250 300 350 400 450

MC

Dat

a

0.5

1

1.5

[GeV]missTE

200 300 400

Even

ts /

20 G

eV

20

40

60

80

100

120

140

160Data(2l)tt(1l)tt

W + JetsVVVtt

Single Topνν→Z

ll→ZQCDpseudoscalar:

(13 TeV)-12.2 fb

CMSPreliminary

=1 GeVDM

=100 GeV, mMEDm (x20)

[GeV]missTE

200 250 300 350 400 450Dat

a / B

kg

0.5

1.0

1.5

Semi-leptonicInclusive hadronic

2 RTT 1 RTT

CMS-EXO-16-006

CMS-EXO-16-006

34




ATLAS ttbar+DM

) [GeV]ϕm(50 100 150 200 250 300 350 400 450 500

) [G

eV]

χm

(

0

50

100

150

200

250

300

21.9 2.3 3.32.82.5 3 1.7

3.2 3.1

2.4

)χ) < 2 m(

ϕm(

= g

q =

gχ

Lim

it on

g

χ χ → ϕ production, ϕ + tt

=13 TeVs, -1L = 13.3 fb

Scalar Mediator

ATLAS Preliminary

)expσ1 ±Expected limit, g = 3.5 (

Observed limit, g = 3.5

[GeV]φm0 50 100 150 200 250 300 350 400 450 500

[GeV

]χ

m

020406080

100120140160180200

Observed limit)expσ1±Expected limit (

Contours for g=3.5

3.3

1.92.1

3.2

1.8

1.7

3.4

3.0

2.5

2.43.1

2.4

2.0

2.1

χ

> 2 m

φm

= gq

= gχ

DM+tt scalar mediator, g

ATLAS Preliminary-1 = 13 TeV, 13.2 fbs

Lim

it on

g

[GeV]Am0 50 100 150 200 250 300 350 400 450

[GeV

]χ

m

020406080

100120140160180200220

Observed limit)expσ1±Expected limit (

Contours for g=3.5

3.3

2.9

1.71.7

2.9

1.73.2

1.6

2.6 3.0

2.7

2.2

1.62.5

1.8

2.1

1.6

χ

> 2 mAm

= gq

= gχ

DM+tt pseudo-scalar mediator, g

ATLAS Preliminary-1 = 13 TeV, 13.2 fbs

Lim

it on

g

) [GeV]am(50 100 150 200 250 300 350 400 450 500

) [G

eV]

χm

(

0

50

100

150

200

250

300

2 2.3 2.9 3.52.7

3.3 2.6 2.3

3.2)χ) < 2 m(

am(

= g

q =

gχ

Lim

it on

g

χ χ → a production, a + tt

=13 TeVs, -1L = 13.3 fb

Pseudoscalar Mediator

ATLAS Preliminary

)expσ1 ±Expected limit, g = 3.5 (

Observed limit, g = 3.5

ATLAS-CONF-2016-077

ATLAS-CONF-2016-077

ATLAS-CONF-2016-076

ATLAS-CONF-2016-076

ATLAS-CONF-2016-050

ATLAS-CONF-2016-050

https://cds.cern.ch/record/2206250







Higgs invisible


Higgs invisible

inv.)→B(H 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

q

0

1

2

3

4

5

6

7

8

9

10

Combined13 TeV7+8 TeV

ObservedExpected

(13 TeV)-1 (8 TeV) + 2.3 fb-1 19.7 fb≤ (7 TeV) + -14.9 fb

PreliminaryCMS

DM mass [GeV]1 10 210 310

]2D

M-n

ucle

on c

ross

sec

tion

[cm

46−10

45−10

44−10

43−10

42−10

41−10

40−10

39−10

LUX (2015)

CDMSlite (2015)

Scalar DM

Fermion DM


Preliminary CMS inv.)<0.20→B(H 90% CL limits

inv.)→B(H 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

q

0

1

2

3

4

5

6

7

8

9

10

CombinedVBF-taggedVH-taggedggH-tagged

ObservedExpected


PreliminaryCMS

37

search for dark matter mediators - institut national de

Documents