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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 J. HewettMini-BSM Workshop
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Universal Extra Dimensions
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All SM fields in TeV -1, 5d, S 1 /Z 2 bulk No branes! translational invariance is preserved tree-level conservation of p 5 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 R c -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
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Universal Extra Dimensions: Bosonic SUSY Phenomenology looks like Supersymmetry: Heavier particles cascade down to LKP LKP: Photon KK state appears as missing E T SUSY-like Spectroscopy Confusion with SUSY if discovered @ LHC ! Chang, Matchev,Schmaltz Spectrum looks like SUSY ! No Tevatron exp’t limits to date!
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1 st Excitation Quark Production @ Tevatron Production Processes ii, v, iii i, iv Rizzo, hep-ph/0106336
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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, Tait Datta, Kong, Matchev
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How to distinguish SUSY from UED II: Observe higher level (n = 2) KK states: –Pair production of q 2 q 2, q 2 g 2, V 2 V 2 –Single production of V 2 via (1) small KK number breaking couplings and (2) from cascade decays of q 2 Discovery reach @ Tevatron/LHC Datta, Kong, Matchev
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How to distinguish SUSY from UED III: Measure the spins of the KK states – Difficult! Decay chains in SUSY and UED: Form charge asymmetry: Works for some, but not all, regions of parameter space Smillie, Webber
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Warped Extra Dimensions
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Localized Gravity: Warped Extra Dimensions Randall, Sundrum Bulk = Slice of AdS 5 5 = -24M 5 3 k 2 k = curvature scale Naturally stablized via Goldberger-Wise Hierarchy is generated by exponential!
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4-d Effective Theory Phenomenology governed by two parameters: or m 1 ~ TeV k/M Pl ≲ 0.1 5-d curvature: |R 5 | = 20k 2 < M 5 2 Davoudiasl, JLH, Rizzo hep-ph/9909255 KK Graviton Wavefunction & Interactions:
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Drell-Yan Production: Randall-Sundrum Graviton Resonances Tevatron: pp G (1) ℓ + ℓ - 1 st & 2 nd KK cross sections Davoudiasl, JLH, Rizzo Different curves for k/M Pl = 0.1 – 1.0 -
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Tevatron limits on RS Gravitons CDF Drell-Yan spectrum
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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 g KK = 8.4g SM !! Precision EW Data Constrains: m 1 A > 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
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Fix 2: Add Fermions in the Bulk Introduces new parameter, related to fermion Yukawa –m f bulk = 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 1 st gauge KK state towards Planck branetowards TeV brane Ghergetta, Pomarol Davoudiasl, JLH, Rizzo LHC Tevatron k/M Pl = 1, 0.1, 0.01
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Graviton Branching Fractions B = 2B ℓℓ dijets tops leptons Higgs gluons WW ZZ/ m 1 = 1 TeV Fermions on TeV brane Fermions in bulk Davoudiasl, JLH, Rizzo, hep-ph/0006041
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Phenomenology Summary for Bulk Fermions Davoudiasl, JLH, Rizzo, hep-ph/0006041 Precision EW
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Fix 3: Brane Kinetic Terms Originally introduced to allow infinite 5 th dimension 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 effects Brane kinetic terms are naturally present!! Their size is determined by the full UV theory Appears in the action for bulk fields: S Gravity = M 5 3 /4 d 4 x r c d (-G) {R (5) + (2/kr c )[ 0 ( ) + ( - )]R (4) } S Gauge = ∫ d 5 x [-F MN F MN /(4g 5 2 ) - (x 5 ) F F /(4g a 2 )] 0, are free parameters Dvali etal Georgi etal
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BKT’s modify KK spectra – masses & couplings Randall-Sundrum model: graviton fields in the bulk KK coupling strength Davoudiasl, JLH, Rizzo, hep-ph/0305086 e+e- +-e+e- +- n=1 23…23… 0 = 0 = 1, -1, -2, -10
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Tevatron Search Reach: RS Gravitons with BKTs 1 st Excitation search reach Davoudiasl, JLH, Rizzo, hep-ph/0305086 Run IRun II, 5 fb -1 Curvature parameter is varied 0 = 0 Allows for very light Gravitons!
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BKT’s modify KK spectra – masses & couplings Randall-Sundrum model: gauge fields in the bulk KK coupling strength Precision EW bound on 1 st KK state Davoudiasl, JLH, Rizzo, hep-ph/0212279See also Carena etal, hep-ph/0212307
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Extend Manifold: AdS 5 x S e + e - + - ( = 1) Drell-Yan (LHC) Davoudiasl, JLH, Rizzo hep-ph/0211377 Gives a forest of KK graviton resonances! Drastically modifies Graviton KK spectrum!
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Higgsless EWSB
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What good is a Higgs anyway?? Generates W,Z Masses Generates fermion Masses Unitarizes scattering amplitudes (W L W L W L W 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!
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Generating Masses Consider a massless 5-d field ∂ 2 = (∂ ∂ - ∂ 5 2 ) = 0 looks like (∂ ∂ - m 2 ) = 0 (KK tower) The curvature of the 5-d wavefunction is related to its mass
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Toy Example: Flat space with U(1) gauge field in bulk with S 1 /Z 2 Orbifold A (y) ~ cos (ny/R) A 5 (y) ~ sin (ny/R) 0 RR 0-mode 1 st KK Orbifold Boundary Conditions: ∂ 5 A = 0 A 5 = 0 0-mode is flat & y independent m 0 = 0 If The Same boundary conditions are applied at both boundaries, 0-mode is massless and U(1) remains unbroken
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A(y) ~ n a n cos(m n y) + b n sin(m n y) ∂ 5 A(y) ~ m n n (-a n sin(m n y) + b n cos(m n y) BC’s: A(y=0) = 0 a n = 0 ∂ 5 A(y= R) = 0 cos(m n R) = 0 ∂ 5 A =0 A =0 1 st KK 0-mode A cannot be flat with these boundary conditions! m n = (n + ½)/R The zero mode is massive! A 5 acts as a Goldstone U(1) is broken Orbifold Boundary Conditions: ∂ 5 A = 0 A 5 = 0
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Exchange gauge KK towers: Conditions on KK masses & couplings: (g 1111 ) 2 = k (g 11k ) 2 4(g 1111 ) 2 M 1 2 = k (g 11k ) 2 M k 2 Necessary, but not sufficient, to guarantee perturbative unitarity! Csaki etal, hep-ph/0305237 Unitarity in Gauge Boson Scattering SM without Higgs violates perturbative unitarity in W L W L W L W L at s ~ 1.7 TeV Higgs restores unitarity if m H < TeV What do we do without a Higgs??
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Realistic Framework: SU(2) L x SU(2) R x U(1) B-L in 5-d Warped bulk Agashe etal hep-ph/0308036 Csaki etal hep-ph/0308038 Planck brane TeV-brane SU(2) R x U(1) B-L U(1) Y SU(2) L x SU(2) R SU(2) D SU(2) Custodial Symmetry is preserved! W R , Z R get Planck scale masses W , Z get TeV scale masses left massless! BC’s restricted by variation of the action at boundary Parameters: = g 5R /g 5L (restricted range) L,Y,B,D brane kinetic terms g 5L fixed by G F, = g 5B /g 5L fixed by M Z
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Gauge KK Spectrum Effects of Brane terms = 1 Schematic KK Spectra Every other neutral gauge KK level is degenerate! Brane terms split this degeneracy And give lighter KK states Masses are fixed by model parameters n ~ z[a n J 1 (m n z) + b n Y 1 (m n z)], z=e ky /k Davoudiasl, JLH, Lillie, Rizzo hep-ph/0312193,0403300
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What are the preferred gauge KK masses? Tension Headache: Colliders PUV in WW scattering Precision EW needs light KK’s needs heavier KK’s Important direct constraints Is there a consistent region of parameter space?
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Precision EW pseudo-oblique parameters Scale of unitarity violation in W L scattering Davoudiasl, JLH, Lillie, Rizzo hep-ph/0312193,0403300
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Collider Constraints with Run I data
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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
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Truly Exotic
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Branon Production Branon - fields associated with brane fluctuations along extra dimensions. Pseudo-goldstone bosons from spontaneous breaking of translational invariance. Are expected to be light. Cembranos, Dobado, Moroto hep-ph/0405286 Creminelli, Strumia, hep-ph/0007267 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 E T in detector
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Production processes: –gg g , qq g , , qg q –Monojet/photon + missing E T - Run I Run II `Projections” N=1 200 pb -1 D0 Monojet data CDF single photon data
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There are numerous discovery opportunities for the Tevatron for the remainder of Run II !
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