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