Status of dark matter searches at colliders Sarah Alam Malik - - PowerPoint PPT Presentation

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Sarah Alam Malik Imperial College London

Status of dark matter searches at colliders

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LHC

✦ The 2016 proton-proton

physics run has ended (26th October).

✦The final integrated luminosity

~40 fb-1 in ATLAS and CMS

✦The target for the whole year

was 25 fb-1!

2011 2012 2015 2016 Energy 7 TeV 8 TeV 13 TeV 13 TeV Integrated luminosity 5 fb-1 20 fb-1 ~4 fb-1 40 fb-1

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LHC

✦Reached peak luminosity of ~ 1.4x1034cm-2s-1

• 40% above design luminosity

✦ Mean # of pp collisions in 2015: ~14 ✦ Mean # of pp collisions in 2016: ~24

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• Expect ~40-50 fb-1/year in 2017 and 2018 - total of ~ 130 fb-1 by end of 2018

LHC

pp run

pp run

Thanks to efforts of accelerator division, LHC performing above expectation

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From Tim Tait

Dark Matter at LHC

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UV complete models, e.g SUSY

Effective field theories

Simplified models, e.g Higgs portal, Z’

Tim Tait

We don’t know what nature has in store for us, cover broadest range of scenarios

Less complete (bottom up) More complete - SUSY (top down)

Dark Matter at LHC

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Signatures for dark matter searches: Mono-X

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Monojet/Mono-V search

Vector mediated DM production Scalar mediated DM production

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One of the highest MET events in the analysis

Monojet/Mono-V search

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Missing transverse energy

✦ At the heart of all DM searches at LHC ✦ Challenging quantity to measure ✦ Sensitive to mis-measurements,

detector effects, backgrounds

✦ Numerous algorithms developed to deal

with anomalous noise producing fake MET and leading to high tail in MET

✦ After cleaning, simulation describes the

data well

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Monojet/Mono-V search

CMS EXO-16-037

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Monojet/Mono-V search

SM SM DM DM

g𝝍 gq Mmed

vector/axial-vector

Excluding mediator mass of upto 2 TeV and DM mass up to 700 GeV

CMS EXO-16-037

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Mono-photon search

Excluding mediator mass of upto 800 GeV and DM mass up to 300 GeV

CMS EXO-16-039

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Mono-Z search

Excluding mediator mass of upto 600 GeV and DM mass up to 200 GeV

Signature : Z(ll) + MET

CMS EXO-16-038

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Monotop

monotop production via (a) neutral flavor-changing current and (b) heavy colored, charged scalar Signature: Hadronically decaying W boson from top quark decay + MET

CMS EXO-16-040

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[GeV]

Med

M

200 400 600 800 1000 1200 1400 1600 1800 2000

[GeV]

DM

m

100 200 300 400 500 600 700

Observed exclusion 95% CL [EXO-16-037]

qq

DM + j/V [EXO-16-039] γ DM + [EXO-16-038]

ll

DM + Z

. 1 2 ≥

2

h

c

Ω

Preliminary CMS ICHEP 2016 Dark Matter Summary

Observed exclusion 95% CL [EXO-16-037]

qq

DM + j/V [EXO-16-039] γ DM + [EXO-16-038]

ll

DM + Z = 1

DM

= 0.25, g

q

g Axial-vector mediator, Dirac DM

Preliminary CMS ICHEP 2016 Dark Matter Summary

[GeV]

Med

M

200 400 600 800 1000 1200 1400 1600 1800 2000

[GeV]

DM

m

100 200 300 400 500 600 700

Observed exclusion 95% CL [EXO-16-037]

qq

DM + j/V [EXO-16-039] γ DM + [EXO-16-038]

ll

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

0.12 ≥

2

h

c

Ω

Preliminary CMS ICHEP 2016 Dark Matter Summary

Observed exclusion 95% CL [EXO-16-037]

qq

DM + j/V [EXO-16-039] γ DM + [EXO-16-038]

ll

DM + Z [EXO-16-040] DM + t (100% FC) = 1

DM

= 0.25, g

q

g Vector mediator, Dirac DM

Preliminary CMS ICHEP 2016 Dark Matter Summary

ICHEP summary of Mono-X searches

DM+j/V

DM+photon

DM+Z

DM+j/V

DM+photon

DM+Z DM+top

Axial-vector mediator Vector mediator

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[GeV]

DM

m

10

2

10

3

10

]

2

[cm

SD

σ

45 −

10

44 −

10

43 −

10

42 −

10

41 −

10

40 −

10

39 −

10

38 −

10

37 −

10

36 −

10

35 −

10

ICHEP 2016

[EXO-16-038]

ll

CMS DM+Z [EXO-16-039] γ CMS DM+ [EXO-16-037]

q q

CMS DM+j/V P i c

• 2

L P i c

• 6
• τ

+

τ Super-K

• τ

+

τ IceCube

ICHEP 2016

Preliminary CMS

= 1

DM

= 0.25, g

q

g Axial-vector med., Dirac DM

• bserved exclusion 90% CL

CMS [EXO-16-037]

qq

CMS DM+j/V [EXO-16-039] γ CMS DM+ [EXO-16-038]

ll

CMS DM+Z

• bserved exclusion 90% CL

DD/ID [arXiv:1601.03729] Pico 2L [arXiv:1510.07754] Pico 60 [arXiv:1503.04858]

• τ

+

τ Super-K [arXiv:1601.00653]

• τ

+

τ IceCube

ICHEP summary of Mono-X searches

[GeV]

DM

m

10

2

10

3

10

]

2

[cm

SI

σ

47 −

10

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

33 −

10

ICHEP 2016

[EXO-16-038]

ll

CMS DM+Z [EXO-16-039] γ CMS DM+ [EXO-16-037]

qq

CMS DM+j/V CDMSLite 2015 CRESST-II LUX 2015 PandaX 2016

ICHEP 2016

Preliminary CMS

= 1

DM

= 0.25, g

q

g Vector med., Dirac DM

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Maximal excluded mass [GeV]

1 10

2

10

3

10

4

10

=1

q

=g

DM

g

t /t b DM + b

=1

q

=g

DM

g

t DM + t

=1

q

=g

DM

g

) q DM + jets/V(q

=0.8

Z'

g =100GeV

DM

=300GeV; m

A

m

) γ γ DM + H(bb/

=0.25

FC

=b

FC

=1, a

DM

g

DM + t

=0.25

q

=1, g

DM

g

)

• l

+

DM + Z(l

=0.25

q

=1, g

DM

g

γ DM +

=0.25

q

=1, g

DM

g

) q DM + jets/V(q

DM exclusions exclusions mediator

• 1

13TeV, 12.9fb

EXO-16-037

• 1

13TeV, 12.9fb

EXO-16-039

• 1

13TeV, 12.9fb

EXO-16-038

• 1

13TeV, 12.9fb

EXO-16-040

• 1

13TeV, 2.3fb

EXO-16-011 EXO-16-012

• 1

13TeV, 12.9fb

EXO-16-037

• 1

13TeV, 2.2fb

EXO-16-005

• 1

13TeV, 2.2fb

B2G-15-007

V AV V AV V AV V S PS S PS S PS V = vector ; AV = axial-vector S = scalar ; PS = pseudoscalar

CMS Preliminary Dark Matter Summary - ICHEP 2016

Observed limits at 95%CL for considered simplified models Theory uncertainties not included

spin 0 mediator spin 1 mediator

= 2 σ / σ = 5 σ / σ = 30 σ / σ

ICHEP summary of Mono-X searches

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Searches for the mediator

low mass region high mass region

Search for narrow resonances decaying into a pair of jets, dijet mass spectrum smoothly falling distribution, no evidence of resonant production

EXO-16-032

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Searches for the mediator

EXO-16-032

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Simplified model exclusion - dijets and mono-X

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Simplified model exclusion - dijets and mono-X

monojet mono photon

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Simplified model exclusion - dijets and mono-X

D i j e t + I S R

Search for new resonances in a dijet system accompanied by a photon or jet Initial-State Radiation (ISR) excludes mediator masses starting from 200 GeV

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Simplified model exclusion - dijets and mono-X

Results from the dijet Trigger-object level analysis constrains mediator mass from 425 GeV

D i j e t + T L A

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Simplified model exclusion - dijets and mono-X

D i j e t 8 T e V

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Simplified model exclusion - dijets and mono-X

D i j e t 1 3 T e V

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Higgs to invisible searches

Search for Higgs boson production via three channels :

• gluon fusion
• vector boson fusion
• associated vector boson production

Combining data from all channels and from 7 TeV, 8 TeV and 13 TeV runs, upper limits on invisible branching fraction of 0.24 at 95% CL

CMS-HIG-16-016

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From Tim Tait

Dark Matter at LHC

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29 Limits on gluino pairs to 4 tops

Limits on stop pairs to 2 tops

Limits on Supersymmetry

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30 Limits on ewk-ino production Zoomed limits on ewk-ino production

Limits on Supersymmetry

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Dark Matter interpretation and comparison with DD

A lot of work/emphasis on interpretation of dark matter searches within framework of simplified models and their comparison with direct detection experiments

❖ ATLAS-CMS Dark Matter Forum : Nov 2014 - Nov 2015 ❖ LPCC Dark Matter Working Group : Nov 2015 - present

Indirect detection experiments Collider Direct detection experiments

None of these experiments alone can claim discovery of WIMPs Understanding complementarity will be key in case of discovery

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✤ LHC running at unprecedented energy of 13 TeV, so far analysed 1/3 of data collected in 2016 ✤ Searches in place to look for DM producing a variety of signatures within top-down models like

SUSY and bottom-up models like EFT and simplified models.

✤ Searches for mediators (dijets) also coming into play and constraining potential mediators

coupling SM to DM

✤ Constraints on SM Higgs decays to invisible particles , upper limit on branching fraction 0.24 ✤ Combination of all these searches could play vital role in determining the characteristics of a

SM-DM interaction in case of discovery.

✤ Combined ATLAS-CMS-theory effort to benchmark a set of simplified models and accurately

elucidate complementarity with direct detection experiments

✤ But so far, no sign of WIMPs. Are we missing something? Are there interesting signatures

we’re not looking for? Expecting ~130 fb-1 of data by end of 2018, presents many

• pportunities.

Summary