1. Overview of Supersymmetry and Dark Matter
John Ellis
King’s College London
(& CERN)

2. Strange Recipe for a Universe
The ‘Standard Model’ of the Universe
indicated by astrophysics and cosmology

3. Relic Density Calculation
Freeze-out from thermal equilibrium
Typical annihilation cross section ~ 3 ✕ cm2
Lower if coannihilation with related particles

4. 300,000
years
Formation
of atoms
Formation
of nuclei 3
minutes
Formation
of protons
& neutrons
1 micro-
second
Appearance
of dark matter?
1 pico-
second
Appearance
of mass?
Appearance
of matter?

5. Classic Dark Matter Signature
Missing transverse energy
carried away by dark matter particles

6. Supersymmetry What else is there? Successful prediction for Higgs mass
Should be < 130 GeV in simple models
Successful predictions for Higgs couplings
Should be within few % of SM values
Could explain the dark matter
Naturalness, GUTs, string, … (???)

7. Higgs Bosons in Supersymmetry
Need 2 complex Higgs doublets
(cancel anomalies, form of SUSY couplings)
8 – 3 = 5 physical Higgs bosons
Scalars h, H; pseudoscalar A; charged H±
Lightest Higgs < MZ at tree level:
Important radiative corrections to mass:
ΔMH|TH ~ 1.5 GeV

8. MSSM Higgs Masses & Couplings
Lightest Higgs mass
up to ~ 130 GeV
Heavy Higgs masses
quite close
Consistent
With LHC

9. Supersymmetric Higgs Couplings
Very similar to those in the SM
Present data do not constrain supersymmetric models
Need future collider to distinguish
H to WW

10. Where May SUSY be Hiding?
Excluded because
stau or stop LSP
Stop
coannihilation
strip
Excluded by ATLAS
Jest + MET search
Excluded by
b  s γ, Bs  μ+μ-
Relic density constraint,
assuming
neutralino LSP
Stau
coannihilation
strip
JE, Olive & Zheng: arXiv:

11. Data Electroweak precision observables Flavour physics observables
gμ - 2
Higgs mass
Dark matter
LHC
Deviation from Standard Model:
Supersymmetry at low scale, or …?
MH = ± 0.3 ± 1.5 GeV
MasterCode: O.Buchmueller, JE et al.

12. O. Buchmueller, R. Cavanaugh, M. Citron, A. De Roeck, M.J. Dolan, J.E., H. Flacher, S. Heinemeyer, G. Isidori,
J. Marrouche, D. Martinez Santos, S. Nakach, K.A. Olive, S. Rogerson, F.J. Ronga, K.J. de Vries, G. Weiglein

13. Search with ~ 8 TeV 13

14. p-value of simple models ~ 5% (also SM)
2012
20/fb
Scan of CMSSM
Buchmueller, JE et al: arXiv:
p-value of simple models ~ 5% (also SM)

15. LHC Reach for Supersymmetry
K. De Vries
(MasterCode)
Confronted with likelihood analysis of CMSSM

16. Favoured values of squark mass also significantly
2012 1 5
20/fb
Reach of LHC at
High luminosity
Squark mass
CMSSM
Buchmueller, JE et al: arXiv:
Favoured values of squark mass also significantly
above pre-LHC, > 1.6 TeV

17. Favoured values of gluino mass significantly
2012 1 5
20/fb
Reach of LHC at
High luminosity
Gluino mass
CMSSM
CMSSM
Buchmueller, JE et al: arXiv:
Favoured values of gluino mass significantly
above pre-LHC, > 1.8 TeV

18. Proton-Proton Colliders: Luminosity and Energy
Future runs of the LHC:
Run 2: 13/14 TeV
Run 3: 14 TeV
HL-LHC: 14 TeV?
(proposed in CERN’s medium-term plan)
HE-LHC: 33 TeV??
(high-field magnets in the LHC tunnel)
VHE-LHC: 100 TeV??
(high-field magnets in 80/100 km tunnel)

19. Exploring the Stau Coannihilation Strip
Disappearing tracks, missing-energy + jets, massive metastable charged particles
Present
sensitivity
Present
sensitivity
Desai, JE, Luo & Marrouche: arXiv:
Prospective sensitivity of LHC Run II

20. What Parts of High-Mass Parameter Space are Allowed?
Imposing dark matter density constraint
Focus-point strip:
A0 ~ 0, large m0/m1/2
Extends to m1/2 ~ 4 TeV
Neutralino has Higgsino mixture
Truncated by mh
O. Buchmueller, JE, K. Olive et al.

21. What Parts of High-Mass Parameter Space are Allowed?
Imposing dark matter density constraint
Stop coannihilation strip:
A0 ~ 3 m0, large m0/m1/2
Extends to m1/2 ~ 13 TeV
Very small mass difference: mstop – mχ
mh very uncertain
HE-LHC
LHC 3000
LHC 300
LHC 8 TeV
O. Buchmueller, JE, K. Olive et al.

22. Exploring the Stop Coannihilation Strip
Extends close to boundary of stop LSP wedge
Extends to masses far beyond current limits
Sensitivity of
LHC Run II
Present
bounds
JE, Olive & Zheng: arXiv:

23. Exploring the Stop Coannihilation Strip
Extended by Sommerfeld effects on annihilations
Compatible with LHC measurement of mh
May extend to mχ = mstop ~ 6500 GeV
JE, Olive & Zheng: arXiv:

24. Exploring the Stop Coannihilation Strip
Present limits extend to mstop ~250 GeV
Future LHC runs should reach mχ=mstop~500 GeV
Unfinished business for FCC-hh?
JE, Olive & Zheng: arXiv:

25. Direct Dark Matter Searches
Compilation of present and future sensitivities
Range calculated
along stop strip
Neutrino
“wall”
JE, Olive & Zheng