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EXTRA DIMENSIONS AT FUTURE HADRON COLLIDERS

EXTRA DIMENSIONS AT FUTURE HADRON COLLIDERS. G.F. Giudice CERN. Desert, e.g. conventional susy need for precision . m < TeV measurements after LHC . Multi-TeV linear collider?. NEW THEORY.

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EXTRA DIMENSIONS AT FUTURE HADRON COLLIDERS

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  1. EXTRA DIMENSIONS AT FUTURE HADRON COLLIDERS G.F. Giudice CERN

  2. Desert, e.g. conventional susy need for precision m < TeV measurements after LHC Multi-TeV linear collider? NEW THEORY New thresholds around 10 TeV need for energy increase to make next step of discoveries VLHC ? LHC is the machine to study the scale of EW breaking VLHC not meant to push new-physics limits by an order of magnitude, but to explore a well-motivated (after some LHC discoveries) energy region

  3. EXTRA DIMENSIONS offer good motivations for explorations with a √s ~ 100 TeV hadron collider • Need to test the theory well above the EW breaking scale • Existence of new thresholds (new physics, not just some more KK) in the 10 TeV region Motivations and implementions of extra dimensions are quite different Not a systematic review, but some examples relevant to VLHC

  4. Any short-distance scale < LSM-1 explained by geometry GRAVITY IN EXTRA DIMENSIONS Fundamental scale at LSM FLAT Arkani Hamed-Dimopoulos-Dvali WARPED Randall-Sundrum

  5. QUANTUM GRAVITY AT LHC Missing energy (flat) Resonances (warped) Graviton emission Contact interactions (loop dominates over tree if gravity is strong) Higgs-radion mixing H

  6. These processes are based on linearized gravity valid at √s <<MD ~TeV • Suitable for LHC • VLHC can extend limits, but the motivations are weak VLHC can probe the region √s >>MD~TeV (only marginal at LHC)  independent test, crucial to verify gravitational nature of new physics

  7. TRANSPLANCKIAN REGIME Planck length quantum-gravity scale classical gravity Schwarzschild radius same regime

  8. b > RS Non-perturbative, but calculable for b>>RS (weak gravitational field) Gravitational scattering: two-jet signal at hadron colliders G.G.-Rattazzi-Wells

  9. At b<RS, no longer calculable Strong indications for black-hole formation Giddings-Thomas, Dimopoulos-Landsberg b < RS  See talk by T. Rizzo At the LHC, limited space for transplanckian region and quantum-gravity pollution At the VLHC, perfect conditions

  10. 2-jets with large Minv and Dh Black holes VLHC Semi-classical approximation Transplanckian QUANTUM GRAVITY Linearized gravity Cisplanckian LHC Jets + missing ET 2-leptons

  11. - + LEP1 Bounds on LLH LLH> 5-10TeV LEP2 MFV EXTRA DIMENSIONS AND THE THEORY OF ELECTROWEAK BREAKING

  12. LSM<1 TeV, LLH>5-10 TeV “Little” hierarchy between LSM and LLH a • New physics at LSM is weakly interacting • No (sizable) tree-level contributions from new physics at LSM • Strongly-interacting physics can only occur at scales larger than LLH

  13. EXTRA DIMENSIONS AND SYMMETRY BREAKING y Scherk-Schwarz breaking R Supersymmetryisbroken Non-local susy breaking _ involves global structure At short distances (<R), susy-breaking effects are suppressed

  14. y y R Z2 n=0 n=1 n=1 n=2 n=2 0 0 pR pR Orbifold projection Z2 : y g-y cos(ny/R) sin(ny/R) +- Chiral theories

  15. SUPERSYMMETRY BREAKING: AN INTERESTING EXAMPLE Barbieri-Hall-Nomura • 5D SM compactified on S1/(Z2×Z2) • Different susy breaking at each boundary • effective theory non-susy (susy recovered at d<R-1) • Higgs boson mass (rather) insensitive to UV • mH = 127 ± 10 GeV

  16. Interesting phenomenology at LHC  • Mass spectrum is non-supersymmetric • one Higgs and two sparticles for each SM particle • LSP stable stop with mass 210 GeV • Strong dynamics at 5/R ~ 1.7 TeV (5-10 TeV in other models) • UV completion  new unknown dynamics within VLHC range

  17. 5-D SU(N) YANG-MILLS Elastic gauge-boson scattering in spin-0 gauge-singlet channel Chivukula-Dicus-He

  18. Higgs/gauge unification as graviton/photon unification in Kaluza-Klein gauge Higgs HIGGS AS EXTRA-DIM COMPONENT OF GAUGE FIELD AM = (Am,A5), A5g A5 +∂5L forbids m2A52 Correct Higgs quantum numbers by projecting out unwanted states with orbifold Yukawa couplings, quartic couplings without reintroducing quadratic divergences Csaki-Grojean-Murayama Burdman-Nomura Scrucca-Serone-Silvestrini EW BROKEN BY BOUNDARY CONDITIONS? Csaki et al.

  19. Calculable description of EW breaking with strong dynamics at 5-10 TeV New realizations of technicolour theories with new elements (extra dimensions, AdS/CFT correspondence) allowing some calculability “Little hierarchy” is satisfied LHC will discover weak physics at LSM New strong-dynamics thresholds at LLH within the reach of VLHC

  20. DESERT • Connection with GUT, strings, quantum gravity • Gauge-coupling unification • Neutrino masses • Suppression of proton decay and flavour violations • Setup for cosmology (inflation, baryogenesis) • NON DESERT • Low-scale string theory,… • Accelerated running, different sin2qW • nR in bulk • Different location of quarks and leptons in bulk • Low-scale inflation, EW baryogenesis

  21. CONCLUSIONS • Extra dimensions ubiquitous ingredient in non-desert scenarios • Physics goals of VLHC quite distinct from those of LHC • Examples: • “Need to test the theory well above the EW breaking scale” • Transplanckian physics: new energy regime to test extra-dim gravity • “Existence of new thresholds (new physics, not just some more KK) in the 10 TeV region” • Extra-dim theories of EW breaking require UV completion at a scale not far from EW

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