Extra Dimensions: From Colliders to Cosmology

• Large Extra Dimensions (Primordial Black Holes)

• Universal Extra Dimensions (KK Bino)

• Warped Extra Dimensions (KK R )

Michell Symposium 2007J. Hewett

Collider signals & DM properties*

* Thanks to T. Tait!

Kaluza-Klein tower of particles

E2 = (pxc)2 + (pyc)2 + (pzc)2 + (pextrac)2 + (mc2)2

In 4 dimensions, looks like a mass!

pextra is quantized = n/R

Small radius Large radius

Small radius gives well separated Kaluza-Klein particles

Large radius gives finely separated Kaluza-Klein particles

Tower of massive particles

Large Extra Dimensions

Motivation: solve the hierarchy problem by removing it!

SM fields confined to 3-brane

Gravity becomes strong in the bulk

Arkani-Hamed, Dimopoulos, Dvali, SLAC-PUB-7801

Gauss’ Law: MPl2 = V MD

2+ , V = Rc

MD = Fundamental scale in the bulk ~ TeV

Kaluza-Klein Modes in a Detector Indirect Signature

Missing Energy Signature pp g + GnJLH Vacavant, Hinchliffe

Graviton Exchange Modified with Running Gravitational Coupling

Insert Form Factor in coupling to

parameterizerunning

M*D-2 [1+q2/t2M*

2 ]-1

Could reduce signal!D=3+4M* = 4 TeV

SM

t=

1

0.5

JLH, Rizzo, to appear

Constraints from Astrophysics/Cosmology

• Supernova CoolingNN NN + Gn can cool supernova too rapidly

• Cosmic Diffuse RaysNN NN + Gn

Gn

• Matter Dominated Universetoo many KK states

• Neutron Star Heat ExcessNN NN + Gn

becomes trapped in neutron star halo

and heats it

-

Cullen, PerelsteinBarger etal, Savage etal

Hannestad, RaffeltHall, Smith

Fairbairn

Hannestad, Raffelt

Astrophysical Constaints*: MD in TeV

= 2 3 4 5

Supernova Cooling 9 0.66 0.01

Cosmic Diffuse -rays Sne 28 1.65 0.02 Sne Cas A 14 1.2 0.02 Neutron Star 39 2.6 0.4

Matter Dominated Universe 85 7 1.5

Neutron Star Heat Excess 700 25 2.8 0.57

Low MD disfavored for ≤ 3

* Can be evaded with hyperbolic manifolds

- Starkman, Stojkovic, Trodden

Hannestad, Raffelt

Black Hole Production @ LHC:

Black Holes produced when s > M*

Classical Approximation: [space curvature << E]

E/2

E/2b

b < Rs(E) BH forms

Geometric Considerations:

Naïve = Rs2(E), details show this holds up to a

factor of a few

Dimopoulos, LandsbergGiddings, Thomas

Black Hole event simulation @ LHC

Decay Properties of Black Holes (after Balding):Decay proceeds by thermal emission of Hawking

radiation

At fixed MBH, higher dimensional BH’s are hotter: N ~ 1/T

higher dimensional BH’s emit fewer quanta, with each quanta having higher energy

Harris etal hep-ph/0411022

Multiplicity for n = 2 to n = 6

n determined to n = 0.75 @ 68% CL for n=2-6 from TH and This procedure doesn’t work for large n

pT distributions of Black Hole decays

Provide good discriminating power for value of n

Generated using modified CHARYBDIS linked to PYTHIA with M* = 1 TeV

Production rate is enormous!

1 per sec at LHC!

JLH, Lillie, Rizzo

Determination of Number of Large Extra Dimensions

Primordial Microscopic Black Holes

• Produced in high-energy collisions in early universe

• Rapid growth by absorption of matter from surrounding plasma

Demand:1.Black Holes not

overclose the universe2.Must not dominate

energy density during BBN

Mass density determined by TI

Conley, Wizansky

Excluded

Empty Bulk

Thermalized Bulk

Universal Extra Dimensions

• All SM fields in TeV-1, 5d, S1/Z2 bulk• No branes! translational invariance is

preserved tree-level conservation of p5

• KK number conserved at tree-level broken at higher order by boundary terms

• KK parity conserved to all orders, (-1)n

Consequences:1. KK excitations only produced in pairs

Relaxation of collider & precision EW constraints Rc

-1 ≥ 300 GeV!

2. Lightest KK particle is stable (LKP) and is Dark Matter candidate

3. Boundary terms separate masses and give SUSY-like spectrum

Appelquist, Cheng, Dobrescu

Universal Extra Dimensions: Bosonic SUSY

Phenomenology looks like Supersymmetry:

Heavier KK particles cascade down to LKP

LKP: Photon KK state appears as missing

ET

SUSY-like Spectroscopy

Confusion with SUSY if discovered @ LHC !

Chang, Matchev,Schmaltz

Spectrum looks like SUSY !

How to distinguish SUSY from UED I:

Observe KK states in e+e- annihilation

Measure their spin via:

•Threshold production, s-wave vs p-wave•Distribution of decay products

•However, could require CLIC energies...

JLH, Rizzo, TaitDatta, Kong, Matchev

How to distinguish SUSY from UED II:

Observe higher level (n = 2) KK states:

– Pair production of q2q2,

q2g2, V2 V2

– Single production of V2 via (1) small KK number breaking couplings and (2) from cascade decays of q2

Discovery reach @ LHC

Datta, Kong, Matchev

How to distinguish SUSY from UED III:

Measure the spins of the KK states @ LHC – Difficult!

Decay chains in SUSY and UED:

Form charge asymmetry:

Works for some, but not all, regions of parameter space

Smillie, Webber

Identity of the LKP

• Boundary terms (similar to SUSY soft-masses) – Induced @ loop-level (vanish @ cut-off)– Determine masses & couplings of entire KK tower

1 ≪ 2 ≪ 3

– Smallest corrections to U(1) KK state

– NLKP is eR(1)

M ~ 1/R > v– LKP is almost pure Bino KK B

(1)

Bino-Wino mass matrix, n=1

Thermal Production and Freeze Out

• Assume LKP in thermal equilibrium in early universe

• Falls out of equilibrium as universe expands

• Below freeze-out, density of LKP WIMPS per co-moving volume is fixed

For 1 TeV KK, Tf = 40 TeV

Co-annihilation

• eR(1) may substantially affect relic density if

it is close in mass to B(1)

• eR(1) has same interaction efficiency

– freeze-out temp is unaffected

• eR(1) left after freeze-out

– Eventually eR(1) e(0) + B(1)

• Net relic density of B(1) is increased

Relic Density

= scaled mass splitting between eR

(1) and B(1)

= 0.05 = 0.01

h2 = 0.11 0.006 yields for R:

Tait, Servant

… 1 flavor

… 5 flavors

5d range of 600-900 GeV

6d range of 425-625 GeV

B(1) alone

More Complete Calculations

WMAP

Kong, Matchev Burnell, Kribs

Quasi-degenerate KK eL

(1)

Quasi-degenerate KK quarks and gluons

= 0.01 solid 0.05 dashed

Add Gravity in the Bulk

mG1 > mB1 mG1 < mB1

KK graviton decays into B(1)

(mWG = KK scale from relic density

without graviton) Shah, Wagner

Super-WIMPS!

Feng, Rajaraman, Takayama

Direct Detection of LKP

• LKP – nucleon scattering:

Tait, Servant

Localized Gravity: Warped Extra Dimensions

Randall, Sundrum

Bulk = Slice of AdS5

5 = -24M53k2

k = curvature scale

Naturally stablized via Goldberger-Wise

Hierarchy is generated by exponential!

Number of Events in Drell-Yan @ LHC

For this same model embedded in a string theory: AdS5 x S

Kaluza-Klein Modes in a Detector: SM on the brane

Davoudiasl, JLH, Rizzo

Unequal spacing signals curved space

Kaluza-Klein Modes in a Detector: SM off the brane

Fermion wavefunctions in the bulk: decreased couplings to light fermions for gauge & graviton KK states

gg Gn ZZ @ LHC

gg gn tt @ LHC

Agashe, Davoudiasl, Perez, Soni

-

Lillie, Randall, Wang

Issue: Top Collimation

Lillie, Randall, Wang

gg gn tt-

g1 = 2 TeV g1 = 4 TeV

Warped Extra Dimension with SO(10) in the bulk

• Splits families amongst 16 of SO(10) with different Z3 charges: Baryon symmetry in bulk

• Lightest Z-odd particle, R’ KK state, is stable

Agashe, Servant

Gives correct relic density for wide range of masses

Bold-face particles have zero-modes

Cosmic Ray Sensitivity to Black Hole Production

Ringwald, TuAnchordoqui etal

No suppression

Summary of Exp’t Constraints on MD

Anchordoqui, FengGoldberg, Shapere