Transcript Document 7248293

Extra Dimensions with Many Inverse
Femptobarns at the Tevatron
• Universal Extra Dimensions
• Warped Extra Dimensions – Beyond RS1
–
–
–
SM in the bulk
Brane Kinetic Terms
Extended Manifolds
Higgsless Models of EWSB
• Truly Exotic
– Branon Production
Mini-BSM Workshop
J. Hewett
Universal Extra Dimensions
Universal Extra Dimensions
Appelquist, Cheng, Dobrescu
• 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
Universal Extra Dimensions: Bosonic SUSY
Phenomenology looks like
Supersymmetry:
Spectrum looks like SUSY !
Heavier particles cascade
down to LKP
LKP: Photon KK state
appears as missing ET
SUSY-like Spectroscopy
Confusion with SUSY if
discovered @ LHC !
No Tevatron exp’t limits to
date!
Chang, Matchev,Schmaltz
1st Excitation Quark Production @ Tevatron
Production Processes
ii, v, iii
i, iv
Rizzo, hep-ph/0106336
How to distinguish SUSY from UED I:
Observe KK states in e+eannihilation
Measure their spin via:
•Threshold production, s-wave
vs p-wave
•Distribution of decay products
•However, could require CLIC
energies...
JLH, Rizzo, Tait
Datta, Kong, Matchev
How to distinguish SUSY from UED II:
Datta, Kong, Matchev
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 @ Tevatron/LHC
How to distinguish SUSY from UED III:
Measure the spins of the KK states – Difficult!
Decay chains in SUSY and UED:
Form charge asymmetry:
Smillie, Webber
Works for some,
but not all,
regions of
parameter space
Warped Extra Dimensions
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!
4-d Effective Theory
Davoudiasl, JLH, Rizzo
hep-ph/9909255
KK Graviton Wavefunction & Interactions:
Phenomenology
governed by two
parameters:
 or m1 ~ TeV
k/MPl ≲ 0.1
5-d curvature:
|R5| = 20k2 < M52
Drell-Yan Production: Randall-Sundrum
Graviton Resonances
Tevatron: pp  G(1)  ℓ+ℓ-
1st & 2nd KK cross sections
Different curves for k/MPl = 0.1 – 1.0
Davoudiasl, JLH, Rizzo
Tevatron limits on RS Gravitons
CDF Drell-Yan spectrum
Peeling the Standard Model off the Brane
• Model building scenarios
require SM bulk fields
–
–
–
–
–
Gauge coupling unification
Supersymmetry breaking
 mass generation
Fermion mass hierarchy
….
SM gauge fields alone in the bulk violate custodial symmetry!
Gauge boson KK towers have coupling gKK = 8.4gSM !!
Precision EW Data Constrains: m1A > 25 TeV   > 100
TeV!
Davoudiasl, JLH, Rizzo
Pomarol
Fix 1: Enlarge EW gauge group to SU(2)L x SU(2)R , preserves
custodial symmetry
Agashe, Sundrum
Fix 2: Add Fermions in the Bulk
Ghergetta, Pomarol
Davoudiasl, JLH, Rizzo
• Introduces new parameter, related to fermion Yukawa
– mfbulk = k, with  ~ O(1) and determines location in bulk
• Zero-mode fermions couple weaker to gauge KK
states than brane fermions
Precision EW & collider constraints on mass of 1st gauge KK state
LHC
Tevatron
k/MPl = 1, 0.1, 0.01
towards Planck brane
towards TeV brane
Graviton Branching Fractions
Fermions on TeV brane
Fermions in bulk
dijets
tops
leptons
Higgs
gluons
WW
ZZ/
B = 2Bℓℓ
m1 = 1 TeV
Davoudiasl, JLH, Rizzo, hep-ph/0006041
Phenomenology Summary for Bulk Fermions
Precision EW
Davoudiasl, JLH, Rizzo, hep-ph/0006041
Fix 3: Brane Kinetic Terms
• Originally introduced to allow infinite 5th dimension
Dvali etal
recover 4-d behavior at short distances
• Generated at loop-order from brane quantum
effects of orbifold and/or matter fields on brane
• Required as brane counter terms for bulk quantum
Georgi etal
effects
Brane kinetic terms are naturally present!!
Their size is determined by the full UV theory
Appears in the action for bulk fields:
SGravity = M53/4  d4x rcd (-G) {R(5) + (2/krc)[0() + (-)]R(4)}
SGauge = ∫ d5x [-FMNFMN/(4g52) - (x5) FF/(4ga2)]
0,  are free parameters
BKT’s modify KK spectra – masses & couplings
Randall-Sundrum model: graviton fields in the bulk
KK coupling strength
e+e-  +-
0 = 0
n=1
2
3
…
Davoudiasl, JLH, Rizzo, hep-ph/0305086
 = 1, -1, -2, -10
Tevatron Search Reach: RS Gravitons with BKTs
1st Excitation search reach
Run I
Run II, 5 fb-1
0 = 0
Curvature parameter is varied
Allows for very light Gravitons!
Davoudiasl, JLH, Rizzo, hep-ph/0305086
BKT’s modify KK spectra – masses & couplings
Randall-Sundrum model: gauge fields in the bulk
KK coupling strength
Davoudiasl, JLH, Rizzo, hep-ph/0212279
Precision EW bound on 1st KK state
See also Carena etal, hep-ph/0212307
Extend Manifold: AdS5 x S
Drastically modifies Graviton KK spectrum!
e+e- +- ( = 1)
Drell-Yan (LHC)
Gives a forest of KK graviton resonances!
Davoudiasl, JLH, Rizzo
hep-ph/0211377
Higgsless EWSB
What good is a Higgs anyway??
• Generates W,Z Masses
• Generates fermion Masses
• Unitarizes scattering amplitudes (WLWL  WLW L )
Do we really need a Higgs?
And get everything we know right….
Our laboratory: Standard Model in 1 extra warped
dimension
 Minimal Particle Content!
Generating Masses
Consider a massless 5-d field
∂2 = (∂∂ - ∂52 )  = 0
looks like
(∂∂ - m2 )  = 0
(KK tower)
The curvature of the 5-d wavefunction  is related
to its mass
Toy Example: Flat space with U(1) gauge field in
bulk with S1/Z2 Orbifold
A(y) ~ cos (ny/R)
A5(y) ~ sin (ny/R)
Orbifold Boundary Conditions:
1st KK
0-mode
∂5A = 0
A5 = 0
0-mode is flat & y independent
0
R
 m0 = 0
If The Same boundary conditions are applied at both boundaries,
0-mode is massless and U(1) remains unbroken
1st KK
Orbifold Boundary Conditions:
∂5A = 0
A5 = 0
0-mode
∂5
A=0
A cannot be flat with these
boundary conditions!
A=0
A(y) ~ n an cos(mny) + bn sin(mny)
∂5A(y) ~ mnn (-an sin(mny) + bn cos(mny)
BC’s:
A(y=0) = 0
 an = 0
∂5A(y=R) = 0  cos(mnR) = 0
mn = (n + ½)/R
The zero mode is massive!
A5 acts as a Goldstone
U(1) is broken
Unitarity in Gauge Boson Scattering
•SM without Higgs violates perturbative unitarity in
WLWL  WLWL at s ~ 1.7 TeV
•Higgs restores unitarity if mH < TeV
What do we do without a Higgs??
Exchange gauge
KK towers:
Conditions on KK masses & couplings:
(g1111)2 = k (g11k)2
Csaki etal, hep-ph/0305237
4(g1111)2 M12 = k (g11k)2 Mk2
Necessary, but not sufficient, to guarantee perturbative unitarity!
Agashe etal hep-ph/0308036
Csaki etal hep-ph/0308038
Realistic Framework:
SU(2)L x SU(2)R x U(1)B-L in 5-d Warped bulk
Planck
BC’s restricted by variation
brane
TeV-brane
of the action at boundary
SU(2)L x SU(2)R
SU(2)R x U(1)B-L
SU(2)D
SU(2) Custodial Symmetry
is preserved!
W, Z get TeV scale masses
U(1)Y
 left massless!
WR, ZR get
Planck
scale masses
Parameters:  = g5R/g5L (restricted range)
L,Y,B,D brane kinetic terms
g5L fixed by GF ,  = g5B/g5L fixed by MZ
Gauge KK Spectrum
n ~ z[an J1(mnz) + bn Y1(mnz)],
z=eky/k
Masses are fixed by model
parameters
Schematic KK Spectra
Every other neutral gauge KK
level is degenerate!
Brane terms split this degeneracy
And give lighter KK states
Davoudiasl, JLH, Lillie, Rizzo
hep-ph/0312193,0403300
Effects of Brane terms
=1
What are the preferred gauge KK masses?
Tension Headache:
PUV in WW scattering
needs light KK’s
Colliders
Important direct
constraints
Precision EW
needs heavier KK’s
Is there a consistent region of parameter space?
Precision EW pseudo-oblique
parameters
Scale of unitarity violation
in WL scattering
Davoudiasl, JLH, Lillie, Rizzo
hep-ph/0312193,0403300
Collider Constraints
with Run I data
Monte Carlo Exploration of Parameter space
Over 3M points scanned
Points which pass all constraints
except PUV: (none pass PUV!)
Prefers light Z’ with small couplings
Perfect for the Tevatron Run II !!
Realistic models put fermions in the bulk
JLH, Lillie, Rizzo
hep-ph/0407059
Truly Exotic
Branon Production
Cembranos, Dobado, Moroto
hep-ph/0405286
Creminelli, Strumia, hep-ph/0007267
Branon - fields associated with brane fluctuations
along extra dimensions. Pseudo-goldstone bosons
from spontaneous breaking of translational
invariance.  Are expected to be light.
Interact with SM fields via T
Parameters: N = # of Branons
f = Brane tension scale
M = Branon mass
•Parity requires branons to be produced in pairs
•Branons couple ~ f-1  are weakly interacting, Dark
Matter candidates
•Appear as missing ET in detector
Production processes:
– gg  g, qq  g, , qg  q
– Monojet/photon + missing ET
Run II `Projections”
Run I
N=1
D0 Monojet data
CDF single photon data
200 pb-1
There are numerous discovery
opportunities for the Tevatron for
the remainder of Run II !