LISHEP The Composite Higgs. Andrea Wulzer. Zürich

Transcription

1 LISHEP 2011 The Composite Higgs Andrea Wulzer Zürich

2 Introduction: Main Goal of the LHC: Unveil the Nature of EWSB mechanism To achieve this, develop and test hypothetical models

3 Introduction: From theory side we assign different priority to different New Physics searches: Look for a motivated scenario Prefer robust (unavoidable) predictions Employ simple models for portable result

4 Introduction: The Elementary (Standard) Higgs Very well motivated: Minimal extension of the EW theory Structural flavor protection (GIM, or MFV) Compatible with Predictive: technically complete until Λ SM TeV

5 Introduction: The Elementary (Standard) Higgs eme However, perceived as provisional solution: & forces Known scalars are emergent (composite) c like pions, or in superconductors GR YM Hierarchy Problem: (from G.Giudice) H m 2 H = δm 2 H SM + δm 2 H BSM = cλ 2 SM + ( m 2 H cλ 2 SM )

6 Introduction: Question for LHC: is there an Hierarchy Problem? Known Solutions: Weakly coupled: Supersymmetry: c Exhaustively studied c Soon excluded or found Strongly coupled: Technicolor: c Constraints from EWPT Composite Higgs: c Higgs helps with EWPT

7 Introduction: Question for LHC: is there an Hierarchy Problem? Known Solutions: Weakly coupled: Supersymmetry: c Exhaustively studied c Soon excluded or found Strongly coupled: Technicolor: c Constraints from EWPT Composite Higgs: c Higgs helps with EWPT

8 Georgi-Kaplan et al., Higgs = Goldstone Boson [G/H=SO(5)/SO(4)]

9 Contino-Pomarol et al., Higgs = Goldstone Boson [G/H=SO(5)/SO(4)] Described by a non-linear sigma-model: φ 2 = f 2 φ = ( ) h 1, h 2, h 3, h 4, f 1 h 2 /f 2 L = µ φ t µ φ = ( 1 + Z[v 2 /f 2 ] ) ( h) 2 + h 2 /f 2 ( h) 2

10 Rattazzi et al., hep-ph/ Higgs = Goldstone Boson [G/H=SO(5)/SO(4)] Indirect effects: A) Corrections to SM: B) Non-ren. Couplings: L = µ φ t µ φ = ( 1 + Z[v 2 /f 2 ] ) ( h) 2 + h 2 /f 2 ( h) 2

11 arxiv: Higgs = Goldstone Boson [G/H=SO(5)/SO(4)] Indirect effects: A) Corrections to SM: B) Non-ren. Couplings: [ O(v 2 /f 2 ) 20% ] c Higgs Br. Ratios Higgs Production gg h In W W hh gg hh hhtt In Double His? Pro(vertex c )

12 arxiv: c Higgs = Goldstone Boson [ O(v 2 /f 2 ) 20% ] Higgs Br. Ratios Higgs Production gg h [G/H=SO(5)/SO(4)] Indirect effects: A) Corrections to SM: B) Non-ren. Couplings: In W W hh NOT FOR THIS RUN gg hh hhtt In Double His? Pro(vertex c )

13 arxiv: , arxiv: Direct effects: Production of Resonances Heavy Vectors ( ρ)c EW Neutral and Charged DY Produced, decay to t, b, W/h Direct bound from EWPT: m ρ >2 TeV Reach: 2 TeV for 100fb 1 LHC@14

14 arxiv: , arxiv: Direct effects: Production of Resonances Heavy Vectors ( ρ)c EW Neutral and Charged DY Produced, decay to t, b, W/h Direct bound from EWPT: m ρ >2 TeV NOT FOR THIS RUN Reach: 2 TeV for 100fb 1 LHC@14

15 hep-ph/ Direct effects: Production of Resonances Kaluza-Klein Gluons Color Octets DY Produced, decay to top pair No Direct bound from EWPT Reach: 4 TeV for 100fb 1 LHC@14

16 hep-ph/ Direct effects: Production of Resonances Kaluza-Klein Gluons Color Octets DY Produced, decay to top pair No Direct bound from EWPT NOT YET SO GOOD Reach: 4 TeV for 100fb 1 LHC@14

17 Sundrum et al., hep-ph/ The Top Partners Required by Partial Compositeness SM n = cos ϕ n elementary n + sin ϕ n composite n, New Colored Fermions Q = (2, 2) 2/3 = [ ] T T5/3 B T 2/3, T = (1, 1)2/3, Strongly coupled to tops

18 arxiv: , arxiv: The Top Partners Signal in Same-Sign Dileptons u d u d t W + L B 1/3 W + l + ν l t b hadrons t W + L T 5/3 W + l + ν l t l + ν l b g t l + ν l b g t b hadrons q W + l + ν l q W hadrons B 1/3 t b hadrons T 5/3 t b hadrons B 1/3 t l + ν l b T 5/3 t l + ν l b q W hadrons q W + l + ν l

19 The Top Partners Under Investigation: σ[fb] { Nespolo, Vanini (from CMS) Gauthier, Etienvre (from ATLAS) LHC@7, Pair prod. M[GeV] 25% cut, few fb 1

20 hep-ph/ The Top Partners Happen to be light in explicit models [From arxiv: ] t' t'' t''' b' t m res m Ρ

21 Conclusions and Outlook At the present stage, top partners and possibly KK gluons are the only visible manifestations of CH Stringent tests of Higgs Compositeness are for a more mature stage of LHC But are we ready for a detailed search program?

22 Conclusions and Outlook Historical weakness of CH models was lack of concrete calculable incarnations Problem solved by Holographic Models in 5d (MCHM, Contino-Pomarol 2004)

23 Conclusions and Outlook arxiv: Limitation of MCHM is technical complication Discrete Models (DCHM) address this issue (A.W., Panico 2011), soon a complete card for event generator Goal is provide a simple but complete reference model for searches (analog of the MSSM for SUSY)