Two Universal Extra Dimensions - susy06.physics.uci.edususy06.physics.uci.edu/talks/4/burdman.pdfMatchev, Schmaltz ’02). Phenomenology of 1 UED with level 2 KK modes (Datta, Kong,

Two Universal Extra DimensionsGustavo Burdman

University of Sao Paulowith Bogdan Dobrescu and Eduardo Ponton,JHEP 0602, 033 (2006) (hep-ph/0506334)

and hep-ph/0601186.

SUSY06, Irvine, CA June 12-17 2006

Two Universal Extra Dimensions – p.1/24

Universal Extra Dimensions

(Appelquist, Cheng, Dobrescu ’01)

If some SM fields propagate in the bulk ⇒ 1/R ∼> 1 TeV .

But if we assume all fields can propagate in the extra dimensions.What is the allowed R ?

p5 conservation in the bulk ⇒ KK number conservation.

Orbifolding breaks KK number −→ KK parity (LKP is stable)


UED Phenomenology

Electroweak precision constraints:

1/R ∼> 300 GeV for 5D1/R ∼> (400 − 600) GeV for 6D

Current direct searches give similar bounds.

But, almost degenerate KK levels ⇒ little energy release. (Cheng,

Matchev, Schmaltz ’02).

Phenomenology of 1 UED with level 2 KK modes (Datta, Kong,

Matchev)


Two Universal Extra Dimensions

Motivation:

Possible to avoid proton decay (Appelquist, Dobrescu, Ponton)

To cancel anomalies ⇒ 3 generations (Dobrescu, Poppitz).

Explore different phenomenology


2 UED: Orbifolding

The Chiral Square

-

6

0

L

L x4

x5

⇒ chiral fermions in the 4D effective theory.


TED: KK Modes

KK Expansion:

Φ =1

πR

∑

j,k

Φ(j,k)(x)

(1 + δj,0)

(

cosjx4 + kx5

R+ cos

kx4 − jx5

R

)

Masses:

Mj,k =1

R

√

j2 + k2 = 0, 1/R,√

2/R, 2/R, · · ·

Presence of the non-eaten GB. For each gauge boson in 6D, ascalar in the spectrum: GH , WH , BH .

6D Gauge bosons:Tower of spin-1Tower of spin-0 (eaten)Tower of spin-0 (in the spectrum)


Localized Operators

Fixed points in the conical singularities:

At (0, 0), (πR, πR) and (0, πR)

Bulk interactions invariant under reflections w.r.t. center of square⇒ ZKK

2 , KK parity: Operators at (0, 0) same as ops. at (πR, πR)

∫ πR

0

dx4

∫ πR

0

dx5 {Lbulk + δ(x4)δ(πR − x5)L2

+ [δ(x4)δ(x5) + δ(πR − x4)δ(πR − x5)]L1}

But, physics above cut-off can also induce localized operators.Assume this respects Zkk

2

⇒ KK parity is preserved ⇒ LKPs


Localized Operators

Operators: Fermion and gauge kinetic terms. E.g.

CpU

Λ2iU−R

ΓµDµU−R+

(

C ′

pU

Λ2iU−R

ΓlDlU−L+ H.c.

)

,

−1

4

CpG

Λ2GµνGµν − 1

2

C ′

pG

Λ2(G45)

2

Will induce:Mass splitting in the KK spectrumKK-number violating couplings


Localized Operators

From:

UV physics above the cut-off. NDA estimate

' Λ2 Nc g26

`6' 1 ⇒ Λ R '

(

32

Nc αs

)1/2

' 10

Also

C ′s ∼ `6`4

∼ 8π

⇒ Effective 4D coupling is

∼ g2s Nc

16π2


Localized Operators

Also contributions from below Λ.E.g. at one-loop, for one of the fermion couplings

C1f

(πΛR)2=

[

−4∑

A

g2AC2(f) +

5

8

∑

i

λ2i

]

1

16π2ln

Λ2

µ2

For one of the gauge couplings

C1A

(πΛR)2 =

−14

3C2(A) +

2

3

∑

f

T (f) +5

12

∑

s

T (s)

× g2A

16π2ln

Λ2

µ2,

(1)

Log enhanced w.r.t. the bare contributions.


Kaluza-Klein Spectrum Level 1

The (1, 0) level spectrum:

400

450

500

550

600

650

700

mass

1�R = 500 GeVGΜH1,0L

WΜH1,0LBΜ

H1,0L GHH1,0LWH

H1,0LBH

H1,0L

Q+3 H1,0LQ+

H1,0L T-H1,0LU-

H1,0LD-

H1,0L

L+H1,0L

E-H1,0LHH1,0L

BH is the LKP ⇒ spin-0 Dark Matter


Kaluza-Klein Spectrum Level 2

The (1, 1) level spectrum:

600

650

700

750

800

850

900

950

1000

1050

mass

1�R = 500 GeVGΜH1,1L

WΜH1,1LBΜ

H1,1LGH

H1,1L

WHH1,1LBH

H1,1L

Q+3 H1,1LQ+

H1,1L T-H1,1LU-

H1,1LD-

H1,1L

L+H1,1L

E-H1,1LHH1,1L


KK-number Violating Interactions

Bulk loops → localized KK-number violation:

KK gluon with zero-mode quarks

gsCqGj,k (qγµT aq)G(j,k)a

µ ,

The spinless adjoint GH couples through the operator

gsCqGj,k

Mj,k(qγµT aq) DµG

(j,k)aH ,

GH , WH and BH coupling proportional to mf .

⇒ Br(XH → tt) ' 100%


TED Phenomenology

1st KK level (1, 0) must be pair produced

2nd KK level (1, 1) can be in s-channel:

qq → G(1,1)µ

qq → W3(1,1)µ

qq → B(1,1)µ


TED Phenomenology

S-Channel (1, 1) gauge boson production at the Tevatron

500 600 700 800 900 1000 1100 1200 130010-1

100

101

102

103

104

PSfrag replacements

σ(

pp→

V(1

,1)

µ)

[fb]

MV (1,1) [GeV]


TED Phenomenology

S-Channel (1, 1) gauge boson production at the LHC

0.50 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.510-1

100

101

102

103

104

105

PSfrag replacements

σ(

pp→

V(1

,1)

µ)

[fb]

MV (1,1) [GeV]


TED Phenomenology

But, decays of W3(1,1)µ and B

(1,1)µ dominated by qq final states

(originated by QCD-dominated loops).

⇒ EW KK modes are Leptophobic


TED Phenomenology

S-channel production of the G(1,1)µ .

@@

@@

@

��

��

�

x ��

��

!!!!!!

aaaaaa

wq

q

G(1,1)µ

U(1,1)−

jet

jet

G(1,1)H

t

tHHHHHH


TED Phenomenology

Production and Decay of W(1,1)µ and B

(1,1)µ

@@

@@

@

��

��

�

x x��q

q

W(1,1)3µ , B

(1,1)µ

t

t

HHHHHH

@@

@@

@

��

��

�

x ��

��

!!!!!!

aaaaaa

wq

q

W(1,1)3µ

L(1,1)−

`

`

W(1,1)3H

t

tHHHHHH


tt Resonances

5 Resonances in the tt spectrum (G(1,1)µ → tt small)

But only 3 will be resolved:

G(1,1)H + W

3(1,1)µ : ∼ 1.10 M1,1

B(1,1)µ + W

3(1,1)H : ∼ 0.97 M1,1

B(1,1)H : ∼ 0.86 M1,1

and M1,1 =√

2/R.


tt Resonances - Tevatron

Production of tt resonances at the Tevatron

400 500 600 700 800 900 1000 110010-1

100

101

102

103

104

PSfrag replacements σ(

pp→

V(1

,1)→

tt)

[fb]

M(

tt)

[GeV]


tt Resonances - Tevatron

Sum of tt pairs from all resonances at the Tevatron

400 500 600 700 800 900 1000 1100M11

10-1

100

101

102

103

104

PSfrag replacements σ(

pp→

V(1

,1)→

tt)

[fb]

M(

tt)

[GeV]


tt Resonances - LHC

0.50 1.0 1.5 2.0 2.5 3.0 3.5Mtt

10-1

100

101

102

103

104

PSfrag replacements

σ(

pp→

V(1

,1)

µ)

[fb]

MV (1,1) [TeV]


Conclusions

Two Universal Extra Dimensions is a well-motivated/distinctscenario

Crucial differences with 1 UED:Spinless adjoints XH , with Br(XH → tt) ' 100%

BH is the LKP

M1,1 =√

2/R: ⇒ 2-level→ 1st level pair is strictly forbidden.

tt rich signals at the Tevatron and LHC

Very different phenomenology

Generic: We can see leptophobic, weakly coupled resonances athadron colliders

SM in UEDs not natural. But basic features of analysis will remain


Documents

Two Universal Extra Dimensions - susy06.physics.uci.edususy06.physics.uci.edu/talks/4/burdman.pdfMatchev, Schmaltz ’02). Phenomenology of 1 UED with level 2 KK modes (Datta, Kong,