Probing the Connection Probing the Connection Between Between

SupersymmetrySupersymmetryand Dark Matterand Dark Matter

Bhaskar Dutta

University of Regina, Canada

Physics Colloquium, TAMU, January 27, 2005

TALK OUTLINETALK OUTLINE

B DecaysB DecaysB. Dutta, C.S. Kim, and S. Oh, PRL 90, 011801 (2003) …

Anomalies in B0 KS and B+ ' K+ Decays

CPCPK.S. Babu, B. Dutta, and R.N. Mohapatra, PRD 65, 016005

(2001) … Strong CP and the SUSY Phase Problems

K.S. Babu, B. Dutta, and R.N. Mohapatra, PRL 85, 5064 (2000) … Electric Dipole Moment of the Muon with Large Neutrino Mixing

NeutrinosNeutrinos B. Dutta, Y. Mimura, and R.N. Mohapatra, PRD 69, 115014

(2004) … CP Violation in SO(10) Model for Neutrinos

String Models and PhenomenologyString Models and PhenomenologyR. Arnowitt, J. Dent, and B. Dutta, PRD 70, 126001 (2004) …

Five Dimensional Cosmology in Horava-Witten M-Theory

My Research Pie

TALK OUTLINETALK OUTLINE

Dark MatterDark MatterR. Arnowitt, B. Dutta, and Y. Santoso, NP B606,  59 (2001) …

Coannihilation Effects in Supergravity and D-Brane Models

Collider PhysicsCollider Physics

B. Dutta, R.N. Mohapatra and  D.J. Muller, PRD 60, (1999) 095005 … Doubly Charged Higgsino of SUSY Left-Right Models at the Tevatron

R. Arnowitt, B. Dutta, T. Kamon, and M. Tanaka, PLB 538, 121 (2002) … Detection of Bs+ at the Tevatron Run II and Constraints of the SUSY Parameter Space

My Research Pie

TALK OUTLINETALK OUTLINE

Today’s TalkToday’s Talk

Recent works on “Collider Physics” and “Dark Matter Physics.”

Introduction to Standard Model (SM)

Reasons for going beyond the SM

Supersymmetric (SUSY) SM

Existing experimental constraints

Prospects of discovering SUSY in the future dark matter experiments

Prospects of discovering SUSY in the future Linear Collider (LC) and Large Hadron Collider (LHC)

Conclusion

Galaxy Formation

t

1 s

107 s

Quantum Gravity

http://www.damtp.cam.ac.uk/user/gr/public/bb_history.html

500 M yrs

SUSY Relic

1043 s

1011 s

Relic Radiation Decouples: WMAP

t = 14 billion years

Road Map to Unified TheoryRoad Map to Unified Theory

x

E

String TheoryString Theory

SUSYSUSYGUTGUTSUSYSUSYGUTGUT

Standard Model (SM)Standard Model (SM)Glashow ’62, Weinberg ’67, Salam ’68Glashow ’62, Weinberg ’67, Salam ’68

Underlying theory: a gauge theory (e.g., QED)Quantum Mechanics + Special Relativity

6 quarks, 6 leptons and gauge particles

How can we see them?

One way to see quarks and leptonsOne way to see quarks and leptons

“Quarks. Neutrons. Mesons. All those particlesYou can’t see. That’s what drove me to drink.But now I can see them!”

Real way to see Top (or Heavy Particles)Real way to see Top (or Heavy Particles)

Standard ModelStandard Model

12s

U(1)SU(2)SU(3)

12s

U(1)SU(2)SU(3)

Predictions were tested in experiments.

1973 B.S. Neutral current

@ CERN SPS (400 GeV p)

1983 M.S. – “W/Z discovery”

@ CERN SppS (540 GeV )

1995 Ph.D. – “Top discovery”

@ Fermilab Tevatron (1.8 TeV )

Remarkable accuracy:

Explains most of the data!

GeV 00210187491

GeV 00210187691

..M

..Mtheory

Z

expZ

GeV 00210187491

GeV 00210187691

..M

..Mtheory

Z

expZ

pp

pp

_

eV 1M eV 1M

eV 10 178 9top M eV 10 178 9top M

eV 10 5 6up ~M eV 10 5 6

up ~M

Too Heavy Too Heavy tt and Non-Zero and Non-Zero

NEUTRINO MASSESNEUTRINO MASSES

Neutrino masses are non zero! The SM can not accommodate nonzero neutrino mass!!! See recent results from SuperKamiokande, SNO, KamLAND, K2K, MACRO (Webb et al.). For future results, see MINOS (Webb et al.), MiniBoone, T2K, …

QUARK MASSESQUARK MASSES

Yet to be discovered

h

Beyond the SMBeyond the SM

But we want to build a theory whichgoes to a higher scale.But we want to build a theory whichgoes to a higher scale.

The SM works very well at ~100 GeV.The SM works very well at ~100 GeV.

Grand Unified Theory

(Str

engt

h o

f F

orce

)1

Three gauge couplingsdo not meet at a singlepoint.

Three gauge couplingsdo not meet at a singlepoint.

Structural Defect in the SMStructural Defect in the SMProblema. The Higgs mass becomes too large at

scale of a few TeV (1000 x Mproton).

b. There should be some new theory at this energy scale and this theory would keep the Higgs mass under control.

The contribution to the Higgs mass

Bosonloop

Fermionloop

2 2F

2 B

= Scale of new physics

Structural Defect in the SMStructural Defect in the SMPossible Solutions (= New Physics)a. Technicolor: Higgs is not a fundamental

particle. Experimental data do not allow this theory any more. It only exists in a movie entertainment world.

b. Extra dimension (ED) at (~)TeV scale. EDs appear at around TeV scale. These theories are not well developed to have clear predictions.

c. Supersymmetric SM

The fundamental law(s) of nature is hypothesized to be symmetric between bosons and fermions.

Fermion (S = ½ ) Boson (S = 0 or 1)

Have they been observed?

➩ Not yet.

Supersymmetric SMSupersymmetric SM

☹

Feynman Diagrams for SUSYFeynman Diagrams for SUSY

Supersymmetric partner of Z boson

Supersymmetric partner of W boson

Lightest neutralinos are always in the final state! This neutralino is the dark matter candidate!!

What do we gain if the theory is supersymmetric?

Grand Unified Picture!

Higgs mass does not become large at any scale.

The top quark mass is predicted to be 150 to 200 GeV. D0 and CDF measured:

Mtop = 178 4 GeV

Supersymmetric UnificationSupersymmetric Unification

MSUSY~TeV

Supersymmetry: Elegant Solution Supersymmetry: Elegant Solution

Whatever happened to elegant solutions?

Many new particles (100 GeV – a few TeV) and many new parameters.

Minimal Supergravity ModelMinimal Supergravity ModelSUSY model with two Higgs fields in the framework of unification:

1) All SUSY masses are unified at the grand unified scale.

2) Two more parameters:

A0

tan

sleptons and squarksfor

masses gauginofor

0

1/2

m

m

sleptons and squarksfor

masses gauginofor

0

1/2

m

m

<H1> , <H2> <H> , tan

SU

SY

SU

SY

Probing the Crucial ConnectionProbing the Crucial Connection

CDM = Neutralino ( )CDM = Neutralino ( )01~

To explain the amount of the CDM, there must be another SUSY particle whose mass must be closer to the neutralino.

Is it possible to observe these features in other experiments?

Dark matter detection?Collider experiments?

CDM = The matter which is present without any electromagnetic interaction.

Ast

rop

hys

ics

Ast

rop

hys

ics

[1] Higgs Mass (Mh):

114 GeV < Mh < 130 GeV

(The Higgs mass depends on the mass parameters m0 and m1/2, and A0 and tan.)

[2] Branching Ratio b s :

CLEO: (3.21 0.47) x 104

SM : (3.62 0.33) x 104

• Excluding parameter space based on the SUSY particle masses.

2SUSY

1

mBr

Existing Bounds from ExperimentsExisting Bounds from Experiments

Mas

s o

f S

qu

arks

an

d S

lep

ton

s

Mass of Gauginos

Excluded Region in SUSY WorldExcluded Region in SUSY World

Exc

lud

ed

Existing Bounds from ExperimentsExisting Bounds from Experiments[3] Magnetic Moment of Muon:

Mas

s o

f S

qu

arks

an

d S

lep

ton

s

Mass of Gauginos

Excluded Region in SUSY WorldExcluded Region in SUSY World

Exc

lud

ed

The relic density is expressed as where CDM = 0.23 0.04.

Neutralino ( ) constitutes the dark matter in this model. It is the lightest and stable particle in our model.

In order to calculate CDM, we need to know the density of the remaining neutralinos when they stopped annihilating each other, “neutralino annihilation,” i.e.

CDM

CDM can be expressed in terms of our mSUGRA parameters.

2

01~

2SUSYm

Existing Bounds from ExperimentsExisting Bounds from Experiments[4] Dark Matter: Allowed region

Co-annihilation [Griest and Seckel ’92]: An accidental near degeneracy occurs naturally for light stau in mSUGRA.

Here . This diagram also contributes to the relic density along with the other neutralino annihilation diagrams. This is a generic feature of any SUSY model.

Other regions (focus point, annihilation funnel): mostly beyond the LHC – But, can be observed at a possible energy upgrade of the LHC - Tripler.

2

20

M

e

01~

011 ~~ MMM

1~

1~

P. McIntyre, Proceedings of DARK2004

Mas

s o

f S

qu

arks

an

d S

lep

ton

s

Mass of Gauginos

Excluded Region in SUSY WorldExcluded Region in SUSY WorldAllowed region

Exc

lud

ed

Small tanSmall tan Region Region

narrow co-annihilation corridor

Mass of Gauginos

Mas

s o

f S

qu

arks

an

d S

lep

ton

s

Large tanLarge tan Region Region

R. Arnowitt, B.D., T. Kamon, M. Tanaka, Phys. Lett. B538, 121 (2002)

R. Arnowitt, B.D., B. Hu, hep-ph/0310103 (talk at BEYOND '03)

A. Lahanas, D.V. Nanopoulos, Phys. Lett. B568, 55 (2003)

J. Ellis et al., Phys. Lett. B565,176 (2003)

H. Baer et al., JHEP 0207, 050 (2002)

narrow co-annihilation corridor

The neutralinos can be detected in the dark matter detectors by scattering:

This recoil can be detected in various ways such as ionization and scintillation.

The existence of SUSY in the nature can be proved in these experiments.

Dark Matter ExperimentsDark Matter Experiments

nucleusnucleus recoilrecoil

01~

01~

R. Arnowitt, B.D. Y. Santoso, B.Hu, Phys. Lett. B505, 177 (2001)

J. Ellis, D. Nanopoulos, K. Olive, Phys. Lett. B508, 65, (2001)

H. Baer et al., JCAP 0309, 007 (2003)

Various ongoing experiments such as

a.DAMA group (Italy) – claiming to have observed some events.

b.CDMS (USA) group – disputing their claim.

Ongoing/future projects: ZEPLIN, GENIUS, Cryoarray, CUORE etc.

J. White et al., Proceedings of DARK2004

106 pb

DAMA

CDMS

Edelweiss

Neutralino-Proton Cross SectionNeutralino-Proton Cross Section

1-2 order of magnitude below the current experimental sensitivity1-2 order of magnitude below the current experimental sensitivity

Collider ExperimentsCollider ExperimentsQuestions:

a.What are the signals from the narrow co-annihilation corridor?

01 ~~

M Small

Collider ExperimentsCollider ExperimentsQuestions:

a.What are the signals from the narrow co-annihilation corridor?

b.What is the accuracy of the measurement on M?

Collider Experiments:

1.Tevatron (2 TeV )

2.LHC (14 TeV )

3.LC (500 or 800 GeV e+e–)

The reach of the Tevatron is not high enough.

We will first discuss the LC since it measures the mass very accurately.

pp

pp

GeV 155011

~MMM ~~

V. Krutelyov, R. Arnowitt, B.D., T. Kamon, P. McIntyre, Y. Santoso, Phys. Lett. B505, 161 (2001); R. Arnowitt, B.D., T. Kamon, M. Tanaka, Phys. Lett. B538, 121 (2002)

01 ~~

Study of SUSY Signals at LCStudy of SUSY Signals at LC

Kinematicallimits

Develop event selection cuts and extract signal from the background

Discovery significance of the parameter space

M = Accuracy of measuring the most crucial parameter

GeV] [500 )( 11 ~~

GeV] [500 )( 11 ~~

GeV] [800 )( 11 ~~

GeV] [800 )( 11 ~~

GeV] [500 )( 02

01 ~~

GeV] [500 )( 02

01 ~~ GeV] [800 )( 0

201 ~~

GeV] [800 )( 02

01 ~~

Stau-pair production

Neutralino-pair production

SUSY Signals at LCSUSY Signals at LC

E() is small because M is

small.

E() is small because M is

small.

GeV 155011

~MMM ~~ GeV 155011

~MMM ~~

01

01 ~~

01

01 ~~

4-fermion WW, ZZ, Z productione.g.,

Two-photon () process

SM Backgrounds at LCSM Backgrounds at LC

Lower energy ’sLower energy ’s

We need to detect e– and e+ going very close to the beam direction (down to 2o or 1o).

RH beamsRH beams

e–

e+

Suppressed by RH polarized electron beamsN4f(500 fb–1) 10k @ 90% RH

eeeeee

WWee

N2(500 fb–1) 13M events!

Number of SUSY events for 500 fb1 of luminosity as a function of M for m0 = 203~220 GeV with all the event selection cuts

We can discover SUSY at LC with 1o!

Number of Events vs. Number of Events vs. MM

R. Arnowitt, B.D., T. Kamon, V. Khotilovich, hep-ph/0411102

N2 = 4 for 1o

N2 = 249 for 2o

NEED: 1o coverage at 500-GeV LC

(M)/M ~ 10%

Accuracy of Mass DeterminationAccuracy of Mass Determination

M (m0) N11 M (“500 fb–1 experiment”)

[GeV] (500 fb–1) 2o Detector 1o Detector

4.76 (205) 122 Not determined

9.53 (210) 787

12.37 (213) 1027

14.27 (215) 1138

~ ~

m1/2=360m1/2=360

R. Arnowitt, B.D., T. Kamon, V. Khotilovich, hep-ph/0411102

GeV 59 1101

.

..

GeV 512 4141

.

..

GeV 514 1141

.

..

GeV 59 0101

.

..

GeV 512 1141

.

..

GeV 514 1141

.

..

GeV 74 0101

.

..

Study of SUSY Signals at the LHCStudy of SUSY Signals at the LHC

The LHC is powerful enough to produce many SUSY particles.

Can we detect the co-annihilation signal (small M)?

01 ~~

Measurement of Measurement of MM at the at the LHCLHCSquark-gluino production cross section is very large.

Key decay:

Signal: >3 (two high and one low energy) + jets (q’s, g’s) + missing energy ( )

Backgrounds: SM and other SUSY processes

01

02 ~~~

01~

tt

A. Arusano, R. Arnowitt, B.D., T. Kamon, D. Toback, P. Wagner

SUSY Signals at the TevatronSUSY Signals at the Tevatron

R. Arnowitt, B.D., T. Kamon, M. Tanaka, Phys. Lett. B538, 121 (2002)

V. Krutelyov, Ph.D. thesis, May 2005 (expected)

V. Krutelyov, R. Arnowitt, B.D., T. Kamon, P. McIntyre, Y. Santoso, Phys. Lett. B505, 161 (2001)

Direct searches

The reach is 200 GeV for m1/2

Promising search: Bs +

SM branching ration: 109

SUSY: 107~108

ConclusionConclusionSUSY cures the problems of the SM.

It fulfills the dream of Grand Unification and explains the dark matter (DM) content.

The minimal supergravity (mSUGRA) model, based on the unification framework, is already constrained by many experiments.

The DM content of the universe requires some specific features of the mSUGRA parameter space e.g. co-annihilation.

The signal of the co-annihilation at the colliders will confirm the model.A linear collider will be able to probe this

signal and accurately measure the mass.We think that the LHC will also be able

to probe this signal.