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Cosmology/DM - IKonstantin Matchev
What Do We Do?
• Says who? How about DOE/NSF
(he who pays the piper orders the tune…)
1. What is the Universe made of?
...
5. Can the laws of Physics be unified?
…
126. What is the cause of the “terrible twos”?
• Trying to answer the really big questions:
The 9 Big Questions
• Are there undiscovered principles of Nature:
new symmetries, new physical laws?• How can we solve the mystery of dark energy?• Are there extra dimensions of space?• Do all forces become one?• Why are there so many kinds of particles?• What is dark matter? How can we make it in the lab?• What are neutrinos telling us?• How did the universe come to be?• What happened to the antimatter?
Heavy elements 0.03%
The need for new physics BSM
Known DM properties
DARK MATTER
• Non-baryonic
DM: precise, unambiguous evidence
for new particles (physics BSM)
• Cold
• Stable
BSM Theory Cookbook• Two approaches:
– A: Take the SM and modify something.– B: Ask your advisor how to do A.
• The Standard Model is a– Lorentz-invariant – gauge theory based on SU(3)xSU(2)xU(1)– of mostly fermions– but also one Higgs – in d=4
• As a rule, we expect new particles
Dark Matter Cookbook
• Invent a model with new particles– Supersymmetry– Universal Extra Dimensions
• Invent a symmetry which guarantees that at least one of them (the lightest) is stable
• Fudge model parameters until the dark matter particle is neutral
• Calculate the dark matter relic density– Use a computer program, e.g. MicrOMEGAs
• Fudge model parameters until you get the correct relic abundance
• If it works, don’t forget to write a paper
Outline of the lectures• All lecture materials are on the web:
http://www.phys.ufl.edu/~matchev/PiTP2007 • Yesterday: became familiar with MicrOMEGAs• Implement the New Minimal Standard Model
• Today: discuss several new physics models and their respective dark matter candidates– concentrate on WIMPs
• Later today: discuss how collider and astro experiments can– determine DM properties – discriminate between alternative models
• Homework exercises throughout today’s lectures
(Davoudiasl, Kitano, Li, Murayama 2004)
42222
!4||
22
1
2
1S
hSH
kSmSSL SS
Useful references
• Jungman, Kamionkowski, Griest, hep-ph/9506380• Bergstrom, hep-ph/0002126• Bertone, Hooper, Silk, hep-ph/0404175• Feng, hep-ph/0405215• Baltz, Battaglia, Peskin, Wizansky, hep-ph/0602187• Murayama, 0704.2276 [hep-ph]• Peskin, 0707.1536 [hep-ph]
DARK MATTER CANDIDATES
• There are many candidates
• Masses and interaction strengths span many, many orders of magnitude
• But not all are equally motivated. Focus on:– WIMPs: natural thermal
relicsDark Matter Scientific Assessment Group,
U.S. DOE/NSF/NASA HEPAP/AAAC Subpanel (2007)
Thermal relic abundance - I• At early times, the DM particles and SM particles X are
in thermal equilibrium
• Freeze-out described by the Boltzmann equation
• accounts for dilution due to Hubble expansion
• describes depletion due to• • describes resupply due to
XX
2 nA
)(3 22eqA nnHn
dt
dn
Hn3
2eqA n
XX
XX
Thermal relic abundance - II• is the total DM annihilation cross-section
• Notice that we do not know the specific final states• The a-term is the one relevant for indirect detection
(ongoing DM annihilations in the galactic halo)• Approximate analytic solution
A
)()( 42 X
A baXX
25)(
)/6(
28
45ln
/3
1
)(
10
*3
*
192
FF
FPl
FF
FF
F
Pl
xxg
xbaMmgc
T
mx
xbaxg
x
M
GeVh
What does WMAP tell us?• 3 unknowns: ; 1constraint mbah A ,, 22
HEPAP LHC/ILC Subpanel (2006)
[band width from k = 0.5 – 2, S and P wave]
1. Thermal relics make up all of the DM:
2. Thermal relics are WIMPs: 2
2
m
kA 1.02 h
Supersymmetry• Extra dimension, but fermionic (’s anticommute)
• SUSY relates particles and superpartners• The SM particles and their superpartners have
– Spins differing by ½– Identical couplings
• Introduce negative R-parity for superpartners– Forbids dangerous interactions allowing proton decay– Is it overrated? (do the HW in SUSY lecture1)– No tree-level contributions to precision EW data– Makes the lightest superpartner stable (dark matter!)
)()()(),( xFxxx
)(
Spin
U(1) SU(2) Up-type Down-type
2 G
graviton
3/2
1 B W 0
1/2
0 Hd
DM CANDIDATES IN MSSM
Neutralinos:
Spin
U(1)
M1
SU(2)
M2
Up-type
Down-type
m m3/2
2 G
graviton
3/2 G
gravitino
1 B W 0
1/2 B
Bino
W 0
Wino
Hu
Higgsino
HdHiggsino
0 Hu Hd
sneutrino
PS. Beyond the MSSM: ,...~,'
~,~ SZR
Neutralino spectrum
• Lightest neutralino:• Mass eigenstates: • Consider the three limiting cases
– Pure Bino: – Pure Wino:– Pure Higgsino:
0
0
0
0
2
1
WZWZ
WZWZ
WZWZ
WZWZ
csMssM
ccMscM
csMccMM
ssMscMM
sin
cos
sin
cos
s
c
s
c
WW
WW
ud HHWB~~~~~
430
2101 ,,, 21 MM
BMM~~, 0
121 00
112
~~, WMM
2/~~~, 000
121 du HHMM
Dark matter codes for SUSY• Public
– Neutdriver (Jungman)– DarkSUSY (Gondolo, Edsjo, Ullio, Bergstrom, Baltz)– MicrOMEGAs (Belanger, Boudjema, Pukhov, Semenov)
• Can also handle generic nonSUSY models• Includes all relevant processes• User-friendly, based on CalcHEP
• Private– IsaRED (Baer, Balazs, Belyaev, Brhlik)– SSARD (Ellis, Falk, Olive)– Drees/Nojiri– Roszkowski– Arnowitt/Nath– Lahanas/Nanopoluos– Bottino/Fornengo
• Use your favorite computer code to check and analyze the following examples
Bino dark matter• Possible channels
• Bino annihilation is suppressed– No s-channel diagrams– 1/M suppression in t-channel– No gauge boson final states– Helicity suppression for fermion final states
• neutralinos are Majorana fermions => S=0• if s-wave, J=0 and helicity flip required on the fermion line
(recall decay)• predominantly p-wave, but still suppression =>
• Binos give too much dark matter, unless other sparticles are light -> upper limits on SUSY masses?
2 ab 2
Wino dark matter• Possible channels
• Unsuppressed annihilation to W pairs• Cannot use threshold suppression
light wino-like chargino• Result: wino relic density too small, unless the wino is
rather heavy• HW: Assume all of the dark matter is pure winos. Use
MicrOMEGAs to find the range of wino masses preferred by cosmology.
WMm ~
Higgsino dark matter• Possible channels
• Unsuppressed annihilation to W and Z pairs• Cannot use threshold suppression
light higgsino-like chargino• Result: higgsino relic density too small, unless the
higgsino is rather heavy• HW: Assume all of the dark matter is pure higgsinos.
Use MicrOMEGAs to find the range of their masses preferred by cosmology.
WMm ~
Mixed neutralino dark matter
• Recap:– Pure Bino gives too much dark matter– Pure Wino gives too little dark matter– Pure Higgsino gives too little dark matter
• How about mixed cases?– Mixed Wino-Higgsino DM: – Mixed Bino-Wino DM:
• e.g. non-universal gaugino masses, rSUGRA
– Mixed Wino-Higgsino DM: • E.g. focus point SUSY
12 ~ MM 21 ~ MM
21 ~ MM Birkedal-Hansen,Nelson 2001
Feng,KM,Wilczek 2000
The exceptional cases• Coannihilations: requires other particles to be
degenerate with the LSP at the level of
• Resonances (“funnels”): h, H/A or Z.
25/~ mTM F
2Re
2
2
2
~~s
AA m
DM stringently constrains the model
Feng, M
atchev, Wilczek (20
00)Focus
point
region
Co-annihilation
region
Bulk
regionYellow: pre-WMAPYellow: pre-WMAPRed: post-WMAP
Too much
dark matter
Cosmology highlights certain regions, detection strategies
• A simple and popular model: universal BC at MGUT
Minimal Supergravity (MSUGRA)
MSSM soft SUSY breaking masses: RGE evolution
• Gaugino universality:
– LSP is not wino
• EWSB condition:
– is typically large
6:2:1~:: 321 MMM
222
2
1~ ZHu Mm
Sneutrino dark matter• Left-handed: direct detection rules it out as a dominant DM
component
– HW: prove it using MicrOMEGAs
• Right-handed? Needs new
interactions to thermalize
and freeze out with the
correct abundance– e.g. U(1)’ gauge interaction
Falk,Olive,Srednicki 1994
Lee,KM,Nasri 2007
Universal Extra Dimensions
• Bosonic extra dimension with a new coordinate y
• An infinite tower of Kaluza-Klein (KK) partnersfor all Standard Model particles• The SM particles and their KK partners have
– Identical spins– Identical couplings
• Automatic KK-parity for KK partners– Makes the lightest KK partner stable (dark matter!)
R
nyx
R
nyxxyx n
n
n sin)(cos)()(),(1
Appelquist,Cheng,Dobrescu 2000
Kaluza-Klein masses• In d=4 we have
• With one extra dimension (u) we get
• Recall particle-wave duality• Periodicity implies quantization of momentum
• KK modes: particles with momentum in the ED:
22222 mpppE zyx
222222 mppppE uzyx
2
up
R
n
R
np
n
Ru
2
22
2
22222222
R
nmpmpppE uzyx
UED Kaluza-Klein mass spectrum
• KK masses at tree-level • KK masses at one-loop
Cheng,KM,Schmaltz 2002Cheng,KM,Schmaltz 2002
Several stable, charged KK particles
Only the LKP is stable.The LKP is neutral (DM!)
KK dark matter • Relic density calculation
– involved, many coannihilations
Kong,KM 2005
• Direct detection– Lower bound on the rate
Cheng,Feng,KM 2002
Burnell,Kribs 2005Servant,Tait 2002
UED in D=6
• 2 extra dimensions• Gauge bosons have 2
extra polarizations– One is eaten as in D=5– The other appears as a
scalar in D=4
• The LKP is now the scalar KK hypercharge boson
Dobrescu,Kong,Mahbubani 2007
Dobrescu,Hooper,Kong,Mahbubani 2007
SUSY or ED or something else?m
ass
•Spins differ by 1/2 same as SM same as SM
•Higher levels no yes no
earth, air,fire, water
baryons, s,dark matter, dark energy
e jet
e
m
jet
b
t
e jet
e
m
jet
b
t