LHC and CosmologyHitoshi Murayama (IPMU Tokyo, Berkeley)
APS Meeting@Denver, May 3, 2009
There are many things we don’t see
Energy Budget of the Universe
• Stars and galaxies are only ~0.5%
• Neutrinos are ~0.1–1.5%
• Rest of ordinary matter (electrons, protons & neutrons) are ~4.4%
• Dark Matter ~23%
• Dark Energy ~73%
• Anti-Matter 0%
• Dark Field (Higgs) ~1062%??
starsneutrinosbaryondark matterdark energy
3
Dark Matter
Solar system revolves at 220km/srequires a lot of mass to keep it inside Milky Way
collision at 4500 km/sec
You don’t want to be there
Cosmological scales
7
matterall atoms
= 5.70+0.39!0.61
• Cold and Neutral
• dark matter must be non-relativistic and clump together by gravitational attraction
• must be electrically neutral
• lifetime longer than age of the Universe
• beyond that, rather little
What do we know?
• must clump to form galaxies, clusters
• imagine
• “Bohr radius”:
• too small m ⇒ won’t fit in a galaxy!
• m >10−22 eV “uncertainty principle” bound (modified from Hu, Barkana, Gruzinov, astro-ph/0003365)
V = GNMm
rrB =
!2
GNMm2
Mass Limits“Uncertainty Principle”
Search for MACHOs(Massive Compact Halo Objects)
Large Magellanic Cloud
Not enough of them!
Dim Stars?
10
MACHO
95% cl
0.2
!6 !2!8 !4 0 20.0
0.4
0.6
f =
!7
EROS!2 + EROS!1upper limit (95% cl)
logM= 2log( /70d)tE
EROS collaborationastro-ph/0607207
• 10-31 GeV to 1050 GeV
• narrowed it down to within 81 orders of magnitude
• a big progress in 75 years since Zwicky
SummaryMass Limits
• if self-coupling too big, will “smooth out” cuspy profile at the galactic center
• some people wanted it (Spergel and Steinhardt, astro-ph/9909386)
• need core < 35 kpc/h from data
σ < 1.7 x 10-25 cm2 (m/GeV)(Yoshida, Springel, White, astro-ph/0006134)
• bullet cluster:
σ < 1.7x10-24 cm2 (m/GeV)(Markevitch et al, astro-ph/0309303)
Self-Coupling
• dominant paradigm: WIMP (Weakly Interacting Massive Particle)
• Stable heavy particle produced in early Universe, left-over from near-complete annihilation
MACHO ⇒ WIMP
ΩM =0.756(n +1)x f
n+1
g1/2σannMPl3
3s08πH0
2 ≈α 2 /(TeV)2
σann
• thermal equilibrium when T>mχ
• Once T<mχ, no more χ created
• if stable, only way to lose them is annihilation
• but universe expands and χ get dilute
• at some point they can’t find each other
• their number in comoving volume “frozen”
G. Jungman et al. JPhysics Reports 267 (1996) 195-373 221
Using the above relations (H = 1.66g$‘2 T 2/mpl and the freezeout condition r = Y~~(G~z~) = H), we
find
(n&)0 = (n&f = 1001(m,m~~g~‘2 +JA+)
N 10-S/[(m,/GeV)((~A~)/10-27 cm3 s-‘)I, (3.3)
where the subscript f denotes the value at freezeout and the subscript 0 denotes the value today.
The current entropy density is so N 4000 cmm3, and the critical density today is
pC II 10-5h2 GeVcmp3, where h is the Hubble constant in units of 100 km s-l Mpc-‘, so the
present mass density in units of the critical density is given by
0,h2 = mxn,/p, N (3 x 1O-27 cm3 C1/(oAv)) . (3.4)
The result is independent of the mass of the WIMP (except for logarithmic corrections), and is
inversely proportional to its annihilation cross section.
Fig. 4 shows numerical solutions to the Boltzmann equation. The equilibrium (solid line) and
actual (dashed lines) abundances per comoving volume are plotted as a function of x = m,/T
0 .01
0 .001
0.0001
10-b
,h 10-s
-; 10-7
c aJ 10-a a
2
10-Q
p lo-‘9
$ lo-”
z 10-m
F! lo-‘3
10 100
x=m/T (time +)
Fig. 4. Comoving number density of a WIMP in the early Universe. The dashed curves are the actual abundance, and
the solid curve is the equilibrium abundance. From [31].
thermal relic
ΩM =0.756(n +1)x f
n+1
g1/2σannMPl3
3s08πH0
2 ≈α 2 /(TeV)2
σann
Finding Dark MatterDirect detection
detector
neutralino
phonon or photon
nucleus
underground laboratory
XMASS800kg LXe
Finding Dark MatterIndirect method
neutralino
!!"##X
## detector
Earth Sun
Ener gy (GeV)
Posit
ron
fract
ion,
(e
+ ) /
((e
+ ) +
(e
– ))
ref. 1PAMELAAesop (ref. 13)HEAT00AMSCAPRICE94HEAT94+95TS93MASS89Muller & Tang 1987 5,6
0.01
0.02
0.1
0.2
0.3
0.4
10!1 1 10 102
PAMELAe+PAMELA
FERMIe+ + e–FERMI
More in session Q8tomorrow 10:45
Nambu-GoldstoneDark Matter
• gauge mediation of SUSY breaking ~100TeV• pseudoNambu-Goldstone boson X ~ 3 TeV• R-axion a ~ GeV, decays to μ+μ-
• annihilation X X→a a→(μ+μ-)(μ+μ-)
BF=2500=overdensity×Breit-WignerIbe, HM, Shirai, Yanagida, in preparation
IbeNakayama
HMYanagida
0902.2914
need for enhancement
• At the freezeout, we need ‹σv›∼10-9GeV-2
• In the galactic halo, we need ‹σv›BR∼10-7GeV-2
• How do we reconcile them?• non-thermal relics• enhancement in the (halo density)2
• attractive force between dark matter particles (Sommerfeld enhancement)
• Our proposal: s-channel resonance just below threshold (Breit-Wigner enhancement)
Breit-Wigner enhancement
• s=4m2+vrel2
• If resonance M is below threshold 4m2, not accessible vrel2<0
• early universe, does not see the BW tail very much
• in halo, dark matter does see the tail
• called “ghost” in nuclear physics
!4 !2 0 2 4 6 8 10vrel2/(10!3c2)
Breit
-Wign
er
small v0
large v0
Nambu-GoldstoneDark Matter
• gauge mediation of SUSY breaking ~100TeV• pseudoNambu-Goldstone boson X ~ 5 TeV• R-axion a ~ GeV, decays to μ+μ-
• decay X→a a→(μ+μ-)(μ+μ-)
IbeNakayama
HMYanagida
0902.2914
τ=1.3×1026 secIbe, HM, Shirai, Yanagida, in preparation
prediction
• bumps in diffuse gamma
annihilation decay
SUSY spectrum
• no dark matter (3-5 TeV) at LHC, but associated SUSY particles within LHC
• The model predicts light gauginos
• gluino < 1 TeV, wino < 300 GeV
• very light gravitino m3/2<16eV with no cosmological problem
• a lot to learn from LHC!
Recreating Big Bang
start this year!
Large Hadron Collider (LHC)
24
Standard WIMP
• SUSY, Universal Extra Dimensions, Little Higgs with T-parity, Warped Extra Dimension, .....
• Can produce dark matter directly at LHC
• missing ET signature
• details depend on models, parameters
Producing Dark Matter in the laboratory
• Mimic Big Bang in the lab• Hope to create invisible
Dark Matter particles • Look for events where
energy and momenta are unbalanced
“missing energy” Emiss
• Something is escaping the detector
⇒Dark Matter!?
4.8Gev EC19.Gev HC
YX hist.of BA.+E.C.0| ! 500cm 500cm|X
0|!500cm
500cm|
Y
26
Supersymmetric Dark Matter
1
10
102
103
104
105
0 1000 2000 3000 4000
ATLAS
Meff
(GeV)
d!
/dM
eff (
Events
/200 G
eV
)
Background
Signal+BG
" !4jets pT>50GeV
" !2jets pT>100GeV
ETmiss>100GeV
ETmiss>ET
sum/4
ST>0.2!
no µ, e in |#|<2.5
Supersymmetryamazing reach Can do many precision
measurements at LHC! L dt = 1, 10, 100, 300 fb-1
A0= 0, tan! = 35, µ > 0
ET
(300 fb-1)miss
ET
(100 fb-1)miss
ET
(10 fb-1)miss
ET
(1 fb-1)miss
g(1000)~
q(1500)
~
g(1500)~
g(2000)~
q(2500)
~
g(2500)~
q(2000)
~
g(3000)~
q(1000)
~
q(500)
~g(500)~
!h2 =
0.4
!h2 =
1
!h 2 =
0.15
h(110)
h(123)
1400
1200
1000
800
600
400
200
50000
1000 1500 2000
m0 (GeV)
m1
/2(G
eV
)
EX
TH
CMS
one year
@1033
one year
@1034
one month
@1033
Fermilab reach: < 500 GeV
one week
@1033cosmologically plausible
region
0
50
100
150
200
250
300
350
400
0 50 100 150 200 250 300 350 400
S5
O1
M! (GeV)"1
0
Ml (
Ge
V)
" R
q
q
W l
l
q’_
g~
g~
g~~
~
~l
0
b
b
W l
l
b
_
~~
~l
0
missing ET, multiple jets, b-jets, (like-sign) di-leptons
SUSY
P80
P80
P80
t
t
t
t
b
b
b
W
W
W
l
l
l
l
q
q’_
_
_
_
q
q’_
W
b
_
technicolor
+little Higgs with T-parity, warped ED with Z3 baryon
New physics looks alike
28
UED
q1
q
W1 l
1l
q’ _
g1
g1
g1 l
t1
b
W1 l
1l
t
_ l
B1
B1
spin 1/2spin 1 spin 0
• Electron-positron collider
• Super-high-tech machine
• Accelerate the beam over ten miles
• Focus beam down to a few nanometers and make them collide
• Precisely measure the dark matter properties
International Linear Collider (ILC) e
lec
tron
so
urc
es
(HE
P a
nd
x-ra
y la
se
r)
linearaccelerator
linear accelerator
x-ra
y la
se
r
ele
ctro
n-p
os
itron
co
llisio
nh
igh
en
erg
y p
hy
sic
s e
xp
erim
en
ts
po
sitro
n s
ou
rce
au
x. p
ositro
n a
nd
2n
d e
lectro
n s
ou
rce
da
mp
ing
ring
da
mp
ing
ring
po
sitro
np
rea
cc
ele
rato
r
e-
e+
e-
33 km
Linear Collider
29
Omega from colliders
SUSY case studyBaltz, Battaglia, Peskin,
Wizansky hep-ph/0602187
How do we know what Dark Matter is?
• cosmological measurement of dark matter
• abundance ∝ σann−1
• detection experiments• scattering cross section
• production at colliders• mass, couplings • can calculate cross sections
• If they agree with each other:⇒ Will know what Dark Matter is
⇒ Will understand universe back to t∼10-10 sec
mass of the Dark Mattercosm
ic a
bundance
WMAP
LHC
ILC
31
400Kyr
13.7Byr
1min10 -10sec
Conclusion
• Major puzzles at the intersection of particle physics and cosmology
• TeV energy scale appears relevant• Dark Matter, Dark Field
• Possibly also origin of baryon asymmetry• We are finally getting there with LHC!• combine LHC with underground, astro,
cosmic ray, CMB, followed by LC