Prospects for Supersymmetry in LHC Run 2

Prospects for Supersymmetry in
LHC Run 2
First 25ns physics collisions this morning
John Ellis
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The
Run 2
SUSY
« Empty » space is unstable
Run 2
SUSY
Dark matter
Run 2
SUSY
Origin of matter
Masses of neutrinos
Run
SUSY
2
Hierarchy problem
SUSY
Inflation
SUSY
Quantum gravity
…
Standard Model!
What lies beyond the Standard Model?
Supersymmetry
New motivations
From LHC Run 1
•  Stabilize electroweak vacuum
•  Successful prediction for Higgs mass
–  Should be < 130 GeV in simple models
•  Successful predictions for couplings
–  Should be within few % of SM values
•  Naturalness, GUTs, string, …, dark matter
Theoretical Constraints on Higgs Mass
•  Large Mh → large self-coupling → blow up at
low-energy scale Λ due to
Instability @
renormalization
1011.1±1.3 GeV
•  Small: renormalization
due to t quark drives
quartic coupling < 0
at some scale Λ
→ vacuum unstable
•  Vacuum could be stabilized by Supersymmetry
Degrassi, Di Vita, Elias-Miro, Giudice, Isodori & Strumia, arXiv:1205.6497
Vacuum Instability in the Standard Model
•  Very sensitive to mt as well as MH
World
average
New D0
New CMS
•  Instability scale: Buttazzo, Degrassi, Giardino, Giudice, Sala, Salvio & Strumia, arXiv:1307.3536
mt = 173.3 ± 1.0 GeV è log10(Λ/GeV) = 11.1 ± 1.3
Instability during Inflation?
Hook, Kearns, Shakya & Zurek: arXiv:1404.5953
•  Do inflation fluctuations drive us over the hill?
•  Then Fokker-Planck evolution
•  Do AdS regions eat us?
–  Disaster if so
–  If not, OK if more inflation
OK if dim-6 operator? Non-minimal gravity coupling?
How to Stabilize a Light Higgs Boson?
•  Top quark destabilizes potential: introduce
introduce stop-like scalar:
•  Can delay collapse of potential:
•  But new coupling must be
fine-tuned to avoid blow-up:
•  Stabilize with new fermions:
–  just like Higgsinos
•  Very like Supersymmetry!
JE + D. Ross
Minimal Supersymmetric Extension of
Standard Model (MSSM)
•  Double up the known particles:
•  Two Higgs doublets
- 5 physical Higgs bosons:
- 3 neutral, 2 charged
•  Lightest neutral supersymmetric Higgs looks like
the single Higgs in the Standard Model
Lightest Supersymmetric Particle
•  Stable in many models because of conservation
of R parity:
R = (-1) 2S –L + 3B
where S = spin, L = lepton #, B = baryon #
•  Particles have R = +1, sparticles R = -1:
Sparticles produced in pairs
Heavier sparticles à lighter sparticles
•  Lightest supersymmetric particle (LSP) stable
LSP as Dark Matter?
•  No strong or electromagnetic interactions
Otherwise would bind to matter
Detectable as anomalous heavy nucleus
•  Possible weakly-interacting scandidates
Sneutrino
(Excluded by LEP, direct searches)
Lightest neutralino χ (partner of Z, H, γ)
Gravitino
(nightmare for detection)
Sample Supersymmetric Models
•  Universal soft supersymmetry breaking at
input GUT scale?
–  For gauginos and all scalars: CMSSM
–  Non-universal Higgs masses: NUHM1,2
•  Strong pressure from LHC (p ~ 0.1)
•  Treat soft supersymmetry-breaking masses as
phenomenological inputs at EW scale
–  pMSSMn (n parameters)
–  With universality motivated by upper limits on
flavour-changing neutral interactions: pMSSM10
•  Less strongly constrained by LHC (p ~ 0.3)
Fit to Constrained MSSM (CMSSM)
2012
20/fb
Allowed
region
extends
to large
masses
Buchmueller, JE et al: arXiv:1312.5250
p-value of simple models ~ 10% (also SM)
m0
Constrained MSSM (CMSSM)
LHC
MET
searches
gµ - 2
2012
20/fb
Buchmueller, JE et al: arXiv:1312.5250
Contributions
to global χ2
from
different
observables
Dark Matter Mechanisms
•  Dark matter density highly constrained by
Planck et al
•  Need particular parameter choices to get right
density
•  Dark matter mechanisms often need specific
relations between sparticle masses, or mixing
•  Near-degeneracy (coannihilation):
–  Stau, stop, chargino, …
•  Direct-channel resonance (funnel)
–  Heavy Higgs A/H, Z, light h
•  Enhanced Higgsino component (focus-point)
Dark Matter Density Mechanisms
2012
20/fb
CMSSM: best fit, 1s , 2s
4000
Buchmueller, JE et al: arXiv:1312.5250
3500
m1/2[GeV]
3000
2500
2000
1500
Estimated reach with
Run 2 of the LHC
1000
500
0
0
Current LHC reach
1000
2000
3000
4000
m0[GeV]
5000
6000
Best-Fit Spectrum in CMSSM
Buchmueller, JE et al: arXiv:1312.5250
Fits to Supersymmetric Models
20121
520/fb
Buchmueller, JE et al: arXiv:1312.5250
Gluino and squark masses
é
Stau
coannihilation
Favoured values of gluino and squark masses
significantly above pre-LHC, ~ 2 TeV or more
H/A
funnel
Probing the CMSSM with the LHC
2012
20/fb
Buchmueller,
Buchmueller,JEJEetetal:al:arXiv:1312.5250
arXiv:1505.04702
Measuring the CMSSM with the LHC
3000/fb
300/fb
LHC
Combined
Combined
LHC
Buchmueller, JE et al: arXiv:1505.04702
Dark Matter in CMSSM, NUHM1/2, pMSSM10
Current LHC reach
Estimated future
LHC reach
Bagnaschi, JE et al: arXiv:1508.01173
Long-Lived Stau in CMSSM, NUHM?
Possible if mstau – mLSP < mτ
Generic possibility in CMSSM, NUHM1, NUHM2
(stau coannihilation region)
Bagnaschi, JE et al: arXiv:1508. 01173
τstau > 103 s gives problems with nucleosynthesis
τstau > 10-7 s gives separated vertex signature
Long-Lived Stau in CMSSM, NUHM?
Possible if mstau – mLSP < mτ
Generic possibility in CMSSM, NUHM
(stau coannihilation region)
2012
Estimated future
LHC reach
Current LHC reach
τstau > 103 s gives problems with nucleosynthesis
τstau > 10-7 s gives separated vertex signature for τ-like decays
Bagnaschi, JE et al: arXiv:1508. 01173
Exploring the Stau Coannihilation Strip
•  Disappearing tracks, missing-energy + jets,
massive metastable charged particles
Present
sensitivity
Desai, JE, Luo & Marrouche: arXiv:1404.5061
Present
sensitivity
Will be covered
By LHC Run 2
Prospective sensitivity of LHC Run 2
Phenomenological
2012
MSSM (pMSSM10)
LHC
searches
De Vries, JE et al: arXiv:1504.03260
FastLim/Atom:
Papucci, Sakurai, Weiler, Zeune
gµ - 2
Contributions
to global χ2
from
different
observables
Best-Fit Spectrum in pMSSM10
Note near-degeneracy of χ01,2, χ±
De Vries, JE et al: arXiv:1504.03260
Anomalous Magnetic Moment of Muon
20121
520/fb
gµ – 2 anomaly
Can be explained
in pMSSM10
é
Cannot be explained
by models with
GUT-scale unification
De Vries, JE et al: arXiv:1504.03260
pMSSM10 can explain experimental measurements
of gµ - 2
Exploring gluinos, squarks @ LHC
20121
pMSSM10
520/fb
Reach of Run 2 missing-energy searches
Run 1 searches
implemented using
FastLim/Atom:
Papucci, Sakurai, Weiler, Zeune
De Vries, JE et al: arXiv:1504.03260
Can reach gluino mass < 2500 (3000) GeV,
squark mass < 3000 (3500) GeV
With 300 (3000)/fb of LHC data
Fits to Supersymmetric Models
20121
520/fb
Squark mass
Reach of LHC at
High luminosity
é
De Vries, JE et al: arXiv:1504.03260
Favoured values of squark mass significantly
above pre-LHC, ~ 1.5 TeV or more
Fits to Supersymmetric Models
20121
520/fb
Gluino mass
Reach of LHC at
High luminosity
é
De Vries, JE et al: arXiv:1504.03260
Favoured values of gluino mass also significantly
above pre-LHC, > 1.2 TeV
Fits to Supersymmetric Models
20121
Stop mass
520/fb
Compressed
stop region
é
De Vries, JE et al: arXiv:1504.03260
Remaining possibility of a light “natural” stop
weighing ~ 400 GeV
Exploring Light Stops @ Run 2
20121
pMSSM10
520/fb
Reach of Run 2
chargino + b
searches
Reach of Run 2
LSP + top
searches
Run 1 searches
implemented using
FastLim/Atom:
Papucci, Sakurai, Weiler, Zeune
De Vries, JE et al: arXiv:1504.03260
Part of region of light “natural” stop weighing
~ 400 GeV can be covered
Direct Dark Matter Searches
•  Compilation of present and future sensitivities
Neutrino
“floor”
Direct Dark Matter Search: pMSSM10
20121
Spin-independent
dark matter
scattering
520/fb
Bagnaschi, JE et al: arXiv:1508. 01173
Estimated reach with
LUX-Zepelin
May also be below
Neutrino ‘floor’
Direct scattering cross-section may be very close to
LUX upper limit, accessible to LZ experiment
Prospects for SUSY Searches
•  Different models, various dark matter mechanisms
•  No guarantees, but good prospects
Bagnaschi, JE et al: arXiv:1508. 01173
Future Circular Colliders
The vision:
explore 10 TeV scale directly (100 TeV pp) + indirectly (e+e-)
Squark-Gluino Plane
Discover 12 TeV squark,
16 TeV gluino @ 5σ
Where May CMSSM be Hiding?
HE-LHC
1
82
721
1
62
821
821
821
4
56221251121
421
124
126
LHC 3000
0
13
LHC 300
7
12 128
0
13
m0 (GeV)
231
231
0.0
6
12
621
124
100
821
031
821 1
821 82
5
12
125
126
1000
621
721
821
128
52
1
621
12
721
2000
7
521
7
12
Stop
coannihilation/
focus-point
strip
6
12
621
521
JE, Olive & Zheng: arXiv:1404.5571
130
521
221
Excluded by
b à s γ, Bs à µ+µ-
821
62 721
1
m1/2 (GeV)
3000
132
621
Excluded by ATLAS
Jest + MET search
coannihilation
strip
821
621
Relic density constraint,
assuming
neutralino LSP
Excluded because
stau or stop LSP
tan β = 10, A0 = 2.3m0, µ > 0
4000
Stau
1.0×104
Exploring the Stop Coannihilation Strip
LHC 8TeV
LHC 300
(monojets), MET
HE-LHC
(monojets), MET
100 TeV
(monojets), MET
LHC 3000
(monojets), MET
•  Compatible with LHC measurement of mh
•  May extend to mχ = mstop ~ 6500 GeV
JE, Olive & Zheng: arXiv:1404.5571
Summary
•  Rumours of the death of SUSY are exaggerated
–  Still the best framework for TeV-scale physics
•  Still the best candidate for cold dark matter
•  Simple models (CMSSM, etc.) under pressure
–  More general models quite healthy
•  Good prospects for LHC Run 2 and for direct
dark matter detection
–  But no guarantees
•  Maybe will need a higher-energy collider?
How Heavy could Dark Matter be in pMSSM?
•  Largest possible mass in pMSSM is along gluino
coannihilation strip: mgluino ~ mneutralino
Nominal
calculation
Cosmological
dark matter
density
•  Extends to mχ = mgluino ~ 8 TeV JE, Luo & Olive: arXiv: 1503.07142
Reaches for Sparticles
Model with compressed spectrum: small gluinoneutralino mass difference
é
é êmg
é =10
mq
200
mgé-mc@GeVD
150
100
50
0
2000
4000
m
c @GeVD
6000
8000
10
Large mass possible in gluino coannihilation
scenario for dark matter
000
Looking forward to the next 100 years
First collisions at 13 TeV
Run 2 already beyond Run 1 for high masses!
10
100
• Plans for future runs of the LHC
LHC vs Dark Matter Searches
•  Compilation of present “mono-jet” sensitivities
•  LHC wins for spin-independent, except small mDM
Buchmueller, Dolan, Malik & McCabe: arXiv:1407.8257; Malik, McCabe, …, JE et al: arXiv:1409.4075
Reaches for Sparticles
LHC:
HE-LHC,
FCC-hh
Reach for the Stop
× possible tip of stop
coannihilation strip
Discover 6.5 TeV stop @ 5σ, exclude 8 TeV @ 95%
Stop mass up to 6.5 TeV possible along coannihilation strip
Direct Dark Matter Search: pMSSM10
20121
Spin-independent
dark matter
scattering
520/fb
pMSSM10
May also be below
Neutrino ‘floor’
De Vries, JE et al: arXiv:1504.03260
Direct scattering cross-section may be very close to
LUX upper limit, accessible to LZ experiment
Positron Fraction Rising (?) with E
Dark Matter? Galactic cosmic rays? Local sources?
AMS Fit with 2-Component Model
Could be galactic cosmic rays + local sources?
Galactic Cosmic Rays Alone?
Blum, Katz& Waxman, arXiv:1305.1324
Rising positron fraction compatible with
model-independent bound on secondary e+
Dark Matter Fits to AMS Positron Data
100
CR
Je+/(Je-+Je+)
µ+ µ+ -
-b
b
W+ WFermi ’11
AMS-02 (new)
Pamela ’10
10-1
10-2
100
101
102
E [GeV]
103
JE, Olive & Spanos, in preparation
Fit with modified GALPROP parameters
+
τ τ Fit
needs Large Annihilation Rate
10-19
< v> [cm3/s]
10-20
10-21
AMS-02 95%
AMS-02 68%
Fermi GC (Ein)
Fermi GC (NFW)
Fermi dSph
HESS GC (Ein)
HESS GC (NFW)
J=0
J=1
+
-
Need cross-section
near unitarity limit
unless big clumping
enhancement
10-22
10-23
10-24 2
10
Planck Collaboration
103
104
mDM [GeV]
105
JE, Olive & Spanos, in preparation
Requires rate above thermal relic value, limits
from dwarf spheroidal galaxies, Planck
New Antiproton/Proton Ratio
Above previous estimate of secondary production
Antiproton/Proton Ratio
10-2
CR
µ+ µ+ -
-p/p
10-3
b -b
W+ WPamela
AMS02
10-4
10-5
Blum, Katz & Waxman: arXiv:1305.1324
10-6
100
101
102
E [GeV]
103
JE, Olive & Spanos, in preparation
GALPROP can give ~ constant ratio > 150 GeV
Antiproton/Proton Ratio
Giesen et al, arXiv:1504.04274
Secondary production compatible with AMS-02
Measuring CMSSM with FCC-ee
FCC-ee
FCC-ee
Z
H+measurements
measurements
LHC 3000/fb
Buchmueller, JE et al: arXiv:1505.04702
Possible FCC-ee Precision Measurements
Precision FCC-ee Measurements
Precision Electroweak
Precision Higgs
Possible Dark Matter Particle Mass
20121
520/fb
Neutralino mass
é
é
Too heavy to
explain GeV
γ excess
De Vries, JE et al: arXiv:1504.03260
pMSSM10 favours smaller masses than in models
with GUT-scale unification
Does Dark Matter Self-Interact?
é
Displacement
between galaxy
and lensing mass
in Abel 3827
Would need mediator mass in MeV range
Dark Matter Fit to AMS Positron Data
∆ χ2 (AMS-02) : τ+ τ- channel
10-19
<σ v> [cm3/s]
10-20
10-21
10-22
10-23
10-24 2
10
J=0
J=1
CL=68%
CL=95%
103
104
105
mDM [GeV]
•  BUT: very large annihilation cross section
~ 3 ✕ 10-23 cm2 >> required for relic density
•  OR: very large boost from halo density
JE, Olive & Spanos, in preparation
fluctuation(s)
Strange Recipe for a Universe
The second
biggest problem
The ‘Standard Model’ of the Universe
indicated by astrophysics and cosmology
100
Galactic Cosmic
Rays Alone?
Je-, Je+ (cm-2 s-1 sr-1 GeV-1)
10-2
0
Fermi ’11
AMS-02
Pamela ’10
10-4
10-6
10-8
10-10
10-12
10-14
el
1
el
1
el
10
10
0
10
1
10
2
10
3
E [GeV]
10-1
1
-2
100
101
102
E [GeV]
=2.9
10-3
CR
Pamela ’10
=2.6
=2.4
103
antiprot/prot
Je+/(Je-+Je+)
10
ee+
e- + e+
Fermi ’10
AMS-02
Can fit positrons > 10 GeV with
modified GALPROP model
_
BUT: problems with e , low-E p
10
-4
10-5
10-6
100
101
102
E [GeV]
103
JE, Olive & Spanos, in preparation
Dark Matter Fit to AMS Positron Data
10-2
10
CR
+ τ τ
Fermi ’11
AMS-02
Pamela ’10
Je-, Je+ [cm-2 s-1 sr-1 GeV-1]
Je+/(Je-+Je+)
100
-1
10-2
10
0
10
1
10
E [GeV]
2
10
3
ee+
e- + e+ (CR)
e + e+ (CR+DM)
Fermi ’10
AMS-02
10-4
10-6
10-8
10-10
10-12
10
+ -
-14
10
0
10
1
10
2
10
E [GeV]
Fit with dark matter annihilation to
τ+τ- and conventional GALPROP parameters
JE, Olive & Spanos, in preparation
3
Antiproton/Proton Ratio
10-2
CR
µ+ µ+ -
-p/p
10-3
b -b
W+ WPamela
10-4
10-5
Blum, Katz & Waxman: arXiv:1305.1324
10-6
100
101
102
E [GeV]
103
Spanos, arXiv:1312.7841
GALPROP can give ~ constant ratio > 150 GeV
Fits with Different Final States
90
80
70
60
µ+ µ+ -
b -b
W+ W-
2
50
40
30
20
10
0
101
102
E [GeV]
JE, Olive & Spanos, in preparation
Best fit with τ+τ-: µ+µ- next best
Galactic Cosmic Rays Alone?
Blum, Katz& Waxman, arXiv:1305.1324
Rising positron fraction compatible with
model-independent bound on secondary e+
Sum of Electron + Positron Spectra
Dark Matter? Galactic cosmic rays? Local sources?
Quality of Fit with
+
ττ
+
-
2
/dof
102
101
100
10-1
2.4
2.5
2.6
2.7
2.8
2.9
el
1
Spanos, arXiv:i1312.7841
Good fit with modified GALPROP parameters
Potential impact of new AMS Data
Harder p spectrum favours
flatter antiproton fraction
Will revolutionize calculations of cosmic-ray backgrounds
Searching for Supersymmetry
Bruno Zumino Memorial
Meeting, CERN
April 27 – 28, 2015
John Ellis
King’s College London
& CERN
Papers with Bruno
Some Personal Memories
•  First meeting Cambridge UK 1970
(phenomenological Lagrangians)
•  Brandeis school, summer 1970
(scale and chiral invariance)
•  Scale symmetry breaking 1971 (+ Weisz, Bruno)
•  Scale anomaly 1972 (+ Chanowitz)
(Anomalous Ward identities)
•  Attempts at superunification 1980/3
(+ Mary K, Bruno, Maiani, Murat G)
Most-Cited Paper with Bruno
No-Renormalization Theorems
Projections for Future
•  Via searches
for “mono-jets”
•  Vector
interaction
•  Sensitive to
mediator mass
Buchmueller, Dolan, Malik & McCabe: arXiv:1407.8257; Malik, McCabe, …, JE et al: arXiv:1409.4075
Supersymmetry
in the sky?
Positron Fraction Rising (?) with E
Dark Matter? Galactic cosmic rays? Local sources?
AMS Fit with 2-Component Model
Could be galactic cosmic rays + local sources?
Dark Matter Fits to AMS Positron Data
100
CR
Je+/(Je-+Je+)
µ+ µ+ -
-b
b
W+ WFermi ’11
AMS-02 (new)
Pamela ’10
10-1
10-2
100
101
102
E [GeV]
103
JE, Olive & Spanos, in preparation
Fit with modified GALPROP parameters
BUT
The required annihilation crosssection is VERY large
+
τ τ Fit
needs Large Annihilation Rate
10-19
< v> [cm3/s]
10-20
10-21
AMS-02 95%
AMS-02 68%
Fermi GC (Ein)
Fermi GC (NFW)
Fermi dSph
HESS GC (Ein)
HESS GC (NFW)
J=0
J=1
+
-
Need cross-section
near unitarity limit
unless big clumping
enhancement
10-22
10-23
10-24 2
10
Planck Collaboration
103
104
mDM [GeV]
105
JE, Olive & Spanos, in preparation
Requires rate above thermal relic value, limits
from dwarf spheroidal galaxies, Planck
Local Source of Cosmic Rays?
Protons
Positrons,
antiprotons
Nearby supernova
~ 2 million years ago?
Evidence from 60Fe on
ocean floor
Kachelriess, Neronov & Semikoz, arXiv:1504.06472
Assume Local Source: Constrain any
extra Dark Matter Contribution
Dark Matter annihilation could give feature
above otherwise smooth distribution
Bergstrom et al, arXiv::1306.3983
Previous Antiproton/Proton Ratio
With previous estimate of secondary production
New Antiproton/Proton Ratio
Above previous estimate of secondary production
Antiproton/Proton Ratio
10
-2
-p/p
10-3
CR
+ µ µ
τ+ τb -b
W+ WPamela
AMS02
Antiprotons
from τèW/Z
bremsstrahlung
10-4
10-5
Blum, Katz & Waxman: arXiv:1305.1324
10-6
100
101
102
E [GeV]
103
JE, Olive & Spanos, in preparation
GALPROP can give ~ constant ratio > 150 GeV
Antiproton/Proton Ratio
Giesen et al, arXiv:1504.04274
Secondary production compatible with AMS-02