1
Bhaskar DuttaTexas A&M University
Current Status of Particle Theory Models
February 5, 2016
2
QuestionsSome Outstanding Issues of High Energy Theory
1. Dark Matter content ( is 27%)
2. Electroweak Scale
3. Ordinary Matter (baryon) Content ( is 5%)
4. Rapid Expansion of the Early Universe
5. Neutrino Mass...
Need: Theory, Experiment and Observation
DMΩ
bΩ
3
Questions
4
Current Status
Collider Experiments: LHCDirect Detection Experiments: DAMA, CDMS, XENON 100,
CoGeNT, LUX etc.Indirect Detection Experiments: Fermi, AMS, PAMELACosmic Microwave Sky: Planck, WMAPNeutrino Experiments: T2K, Daya Bay, Double CHOOZ,
RENO etc.
What have we learnt? What is the status of theory models? What do we expect in the near future?Are we closing in?
5
(i) What have we learnt so far?LHC, Direct and Indirect Detection Experiments, Planck Data, Neutrino Experiments
(ii) Dark Matter: History
(iii) Dark Matter and Ordinary MatterContents
(iv) Dark Matter at the LHC
(v) Concluding Insights
Presentation Outline
6
Large Hadron Collider(LHC)
Proton-Proton Collision
7
Higgs Boson has been found (Mass (mh) 125 GeV)+Completes Standard Model
3 families of quarks, leptons, Gauge Bosons (force carriers) : W±, Z, γ, g
LHC: Higgs
Higgs mechanism breaks the SM symmetry spontaneously and generates mass for quarks, leptons, W, Z and Higgs
Symmetry breaking scale(Electroweak scale): 246 GeV
Much lower than the Planck scale: 1.22 x 1019 GeV
Mz=91.18 GeV, Mw=80.22 GeV
8
• Higgs mass increases rapidly with scale mh2= m0
2+k Λ2: divergence problem solution needs fine tuning (1 part in 1032)
• SM prediction: mh<850 GeV to satisfy the unitarity in W scattering
• Fine tuning problem solved in supersymmetry due to fermions ↔ bosons symmetry
• Higgs mass predicted in SUSY Model?Minimal Supersymmetry Standard Model (MSSM):
loop correction prediction: mh<135 GeV
•Measured mass (125 GeV) appears in the tight MSSM window
LHC: Higgs
+= β2222 CosMM Zh Mz=91.18 GeV
Fundamental law of nature hypothesized to besymmetric between bosons and fermions
Fermion ↔Boson
LHC: Supersymmetrized SM
9
Lightest neutralinois in the final state dark matter candidate!!
New colored particles: Squarks, gluinosNew non-colored particles: Sleptons, Neutralinos, Charginos etc
Minimal SupersymmetricStandard Model (MSSM)
10
LHC: SupersymmetryMotivation: supersymmetry (SUSY) or beyond the SMSM does not provide solutions to any of the outstanding issues
e.g., 27% of the Universe (DM) Higgs mass divergence problem Baryon content Origin of Electroweak scale (associated with Higgs Boson) Inflation Neutrino mass
SUSY is very useful in explaining some of these issues
Have we seen SUSY? Not yet
11
LHC: Supersymmetry
Most models predict: 1-3 TeV (colored particle masses)So far: No colored particle up to 1.5 TeV
Non-colored SUSY particles: 100 GeV to 1-2 TeV(Major role in the DM content of the Universe)
Weak LHC bound for non-colored particles hole in searches!
Trouble in Models with very tight correlation between colored and non-colored particles , e.g., minimal SUGRA/CMSSM
LHC + Direct Detection + Indirect Detection quite constraining
New Excess at the LHC?
12
Direct Detection Experiments
Any parameter space left?
DM
DM
CDMS, DAMA, CoGeNT:Signal for Low mass DM
LUX: No signal for Low or High DM mass
arXiv:1310.8214
Status of New physics/SUSY in the direct detection experiments:
• Astrophysical and nuclear matrix element uncertainties• No signal: some particle physics models are ruled out
Indirect Detection: Fermi
13
: smaller than the thermal valueoannv ><σ
>< vannσ
Thermal DM 27%
Gamma-rays constraints: Dwarf spheroidals, Galactic center
Experimental constraints:
Fermi Collaboration: arXiv:1503.02641
LargeCross-sectionis constrained
Indirect Detection Excess of positrons has been found by both
AMS, PAMELA and Fermi
14
Dark Matter Mass: More than 100 GeVNo anti-proton excess found?Theory Models predictions: The excess will fall off
Pulsar can produce this excess
Is this excess due toDM annihilation?
Need Larger Cross-section (larger than the thermal cross-section 3x 10-26 cm3/sec)
15
Latest result from Planck
http://public.planck.fr/images/resultats/2014-matiere-noire/plot_constraints_planck2014.jpg
16
Probing Dark Matter
SM
Dark Energy68%
Atoms5%
Dark Matter27% +
Collider experiments
Overlapping region
DM content (CMB) + overlapping region:
Thermal history, particle physics models, astrophysics
Planck MeasurementsAccurate measurement of cosmic microwave backgroundPrecision cosmology
Number of relativistic degrees of freedom: Neff = 3.04 ± 0.18 (neutrinos)
For Inflation:What is the scale of inflation?
Can we have more than one inflaton field?
What types of inflation models are okay?
Can we accommodate these models in particle physics framework?
17
NeutrinosRecent Neutrino Data:Accurate measurements of 2 mass differences and 3 mixing angles
18
Questions:Dirac or Majorana type? Charge-Parity violation? Exact masses? How many?
Status of GUT (Grand Unified Theory) ?
SO(10)?
Summary
Direct Production at the collider: SUSY lurking around? More Higgs?
Direct Detection and LHC: Low/high mass DM particle?
Indirect Detection and LHC: DM thermal/non-thermal/multi-component? Seen a signal already at AMS?
Neutrinos experiments: CP phase? More than 3 neutrinos? Do we have GUT (Grand Unified Theory) model?
Planck: Model of Inflation?
19
DM
~ 0.0000001 seconds
Dark Matter: When?
20
Now
Dark Matter: ThermalProduction of thermal non-relativistic DM:
particlesSMDMDM ⇔+
particlesSMDMDM ⇒+
Universe cools (T<mDM)
particlesSMDMDM ⇔+
Boltzmann equation
][3 2,
2eqDMDMeqDM
DM nnvHndt
dn−−=+ σ
∫
∫+−
+−
=
6
/)(2
31
3
6
/)(2
31
3
)2(
)2(21
21
π
πσ
σ TEE
TEE
eq epdpd
vepdpd
vvolnostppfdgn /.
)2(),(
3
3
≡= ∫ π
m/T
3* Tgn
snY
s
==Y
Dark Matter: Thermal
Freeze-Out: Hubble expansion dominates over the interaction rate
22
v1~DM σρc
DMDM nm=Ω
20~ DM
fmT
Dark Matter content:
Assuming : 2
2
~vχ
χασmf
αχ~O(10-2) with mχ ~ O(100) GeVleads to the correct relic abundance
m/T
freeze out
scm3
26103v −×=σY becomes constant for T>Tf
Nc G
Hπ
ρ83 2
0=
Y
Y~10-11 for mχ~100 GeVto satisfy the DM content
Thermal Dark Matter
DM particle + DM Particle SM particles
Annihilation Cross-section Rate:
23
>< vannσ
DM
DM
DM
DM
f: SM particles; h, H, A: various Higgs, : SUSY particleNote: All the particles in the diagram are colorless
v1~DM σ
Ω
DM Abundance:
f~
scm3
26103v −×=σWe need to satisfy thermal DM requirement
24
Suitable DM Candidate: Weakly Interacting Massive Particle (WIMP)
Typical in Physics beyond the SM (LSP, LKP, …)
Most Common: Neutralino (SUSY Models)
Neutralino: Mixture of Wino, Higgsino and Bino
Neutralino can give rise to larger/smaller annihilation rate
Larger/Smaller Annihilation Non-thermal Models
Thermal Dark Matter
Thermal Dark Matter
Dark Energy68%
Atoms5%
Dark Matter27%
v1~DM σ
Ω
20~ DM
fmT
Dark Matter content:
Weak scale physics :
2
2
~vχ
χασmf
αχ~O(10-2) with mχ ~ O(100) GeVleads to the correct relic abundance
freeze out
scm3
26103v −×=σ
Mp
Inflation
TeV
GeV
MeVBBN
~ WIMP freeze-out
Non-standard thermal history at is generic in some explicit high Scale theories.
fTfTT >
Acharya, Kumar, Bobkov, Kane, Shao’08Acharya, Kane, Watson, Kumar’09Allahverdi, Cicoli, Dutta, Sinha,’13
Status of Thermal DMThermal equilibrium above is an assumption.
DM content will be different in non-standard thermal histories
Barrow’82, Kamionkowski, Turner’90
DM will be a strong probe of the thermal history after it is discovered and a model is established.
27
Non-Thermal DM
Decay of moduli/heavy field occurs at:
)MeV5(TeV100
~2/3
2/1
φmcTr
Tr ~ MeV : Not allowed by BBN
[Moduli : heavy scalar fields gravitationally coupled to matter]
>< vannσ : different from thermal average, is not 27% Non-thermal DM can be a solution
DM from the decay of heavy scalar field, e.g., Moduli decay
For Tr<Tf: Non-thermal dark matter
v1~DM σ
Ω
Decay of moduli produce both DM and ordinary matter
Moroi, Randall’99; Acharya, Kane, Watson’08,Randall; Kitano, Murayama, Ratz’08; Dutta, Leblond, Sinha’09; Allahverdi, Cicoli, Dutta, Sinha,’13
MpInflatio
TeV
GeV
MeV
28
Non-thermal DM
Non-thermal DM Production from moduli decay
Ordinary Matter and DM from moduli decay ⇒ Cladogenesis of DM and Ordinary Matter (Baryons) [Allaverdi, Dutta, Sinha’11]
Cladogenesis: is an evolutionary splitting event in a species in which each branch and its smaller branches forms a "clade", an evolutionary mechanism and a process of adaptive evolution that leads to the development of a greater variety of sister species.
29
Mp
Inflation
TeV
GeV
MeVBBN
~ WIMP freeze-out
Mp
Inflation
TeV
GeV
MeVBBN
Non-thermal DM
Large multicomponent/non-thermal; Small Non-thermal
Probe directly at Indirect and Collider experiments
>< vannσ
DM content: summary
>< vannσ
30
Dark Matter at the LHCAnnihilation of lightest neutralinos (DM particles) quarks, leptons etc.At the LHC: proton + proton DM particles
DM Annihilation diagrams: mostly non-colored particlese.g., sleptons, staus, charginos, neutralinos, etc.
How do we produce these non-colored particles and the DM particle at the LHC? Can we measure the annihilation cross-section ?
1. Cascade decays of squarks and gluinos2. Vector Boson fusion
>< vannσ
31
The signal : SM particles + DM particle(Missing energy)
Via Cascade decays at the LHC
(or l+l-, τ+τ−)DM
DMColored particles are produced and they decay finally into the weakly interacting stable particle
High PT jet
(or l+l-, τ+τ−)LHC is very complicated
DM at the LHC Via VBF
32
LHC has a blind spot for productions of non-colored particle
The W boson (colorless) coming out of high energy protons can produce colorless particlesVector Boson Fusion(VBF
Special search strategy needed to extract the signal
New way of understanding DM or new physicssector at the LHC
Refs (For example): A. Datta, P. Konar, and B. Mukhopadhyaya, 02. G. Giudice, T. Han, K. Wang, and L.T. Wang, 13
A.G. Delannoy, B. Dutta, A. Gurrola, W. Johns, T. Kamon, E. Luiggi, A. Melo, P. Sheldon, K. Sinha, K. Wang, S. Wu, ‘13
Dutta, Gurrola, Kamon, John, Sinha, Shledon; ‘13
33
Cross Sections via VBFDM Via W at the LHCjjpp 0
10
1~~ χχ→
DM
34
DM Content via VBF
Simultaneous fit of various observables:
How to check that LHC observations lead to correct dark matter content? Measure Ω at the LHC (Ω is 27%: Planck Measurement)
New particle at the LHC?
35
Q
g New Quarks: Q, New Leptons: L New scalar particles: X
Do we need dark matter particles to explain the data?
Dutta, Gao, Ghosh, Gogoladze, Li, e-Print: e-Print: arXiv:1512.05439Dutta, Gao, Ghosh, Gogoladze, Li, Walker, e-Print: e-Print: arXiv:1601.00866
36
Concluding Insights Model ideas have constraints from LHC, Planck,
Neutrino data, direct and indirect detection constraints Higgs mass is within the supersymmetry model prediction
window LHC measurements so far seem to be preferring
Non-thermal DMNon-thermal scenarios can allow us to understand the
Ordinary Matter-Dark Matter coincidence puzzle
Determination of the property of DM is crucial: LHC and Indirect detections identify DM model
Need to investigate colorless particles (suitable for DM calculation) at the LHC
37
Acknowledgement
Kechen Wang (PhD 2014), Tathagata Ghosh, Sean Wu,Yu GaoStudents/Post-Doctoral Fellow:
Rouzbeh Allahverdi, Richard Arnowitt, Michele Cicoli, James Dent, Ricardo Eusebi, Ilia Gogoladze, Alfredo Gurrola, Teruki Kamon, Tainjun Li, Rabindra Mohapatra, Dimitri Nanopoulos, Farinaldo Queirez, Fernando Quevedo, Qaisar Shafi, Kuver Sinha, Louis Strigari, David Toback, Joel Walker
Research Funded by Department of Energy (DOE)
Faculty from TAMU and other places: