1. Vectorlike Confinement and its Signatures at the LHC Can Kılıç work done with Takemichi Okui and Raman Sundrum arXiv: 0906.0577

2. Introduction LHC coming, expectations shaped by the hierarchy problem. Known solutions constrained by experiment. Possible scenarios. Concept of meso-tuning. Impact on discovery potential at the LHC. Part of NP may be accessible. Need guiding principle. Theoretical simplicity / safety from PO at low energy. (rich phenomenology at higher energies) Define Vectorlike Confinement: –new vectorlike fermions –a new strong gauge force –(very weak interactions relevant for decay) LHC phenomenology dominated by hyperhadrons.

3. Attractive features Precedent: Analogy to QED + low energy QCD. Signatures: pair production, resonance. can decay, is stable up to weak interactions. Mirrored in VC. Safety: “Gauge-mediation” is flavor blind. Mass scale set by confinement, separated from EWSB. Rich phenomenology: A minimal theory naturally gives rise to an array of distinct collider signatures (multi GB, CHAMPs, other exotica), some new features.

4. Deja-Vu? Not TC. Different motivation / structure / signatures. TC must have chiral fermions for EWSB, which impacts PEW. Generating masses leads to flavor problems in TC. Connected in the bigger picture? Can use same tools (analog computer) VC as a strawman model

5. Outline Theoretical Structure Phenomenological Lagrangian Representative Case Studies –A subtlety in the minimal model –CHAMPs and EW gauge bosons –Multijets –R Hadrons –DM, cascades, other possibilities Conclusion

6. A Brief History of QCD Begin by strongest interactions (u,d only) Focus on ,ρ Confinement, flavor symmetry (Pseudo) Goldstones: transform in adjoint of flavor group.  ’s and baryons stable ρ lightest state, decays to 2 , becomes special once we add U(1) em

7. A Brief History of QCD Consequences of turning on U(1) em (q u = 2/3, q d = -1/3) ρ is the lightest meson which can be interpolated by –ρ/γ mixing –resonant production –  charges – anomalous,

8. Both up and down number still conserved, stable, turn on weak interactions. (4-fermion operators) Up and down numbers no longer conserved, baryon number still conserved. Need light particles for to decay, introduce non-strongly interacting particles. induces as well as neutron decay (proton stable) A Brief History of QCD

9. Could Lightning Strike Twice? From a simple UV theory to rich IR Physics Hypercolor: SU(N) gauge theory with F vectorlike flavors in the fundamental representation. Scale Λ HC. (F chosen such that theory confines) Flavor symmetry Conserved number for each flavor. (Pseudo)Goldstones: we consider and baryons stable at this point is the lightest meson, decays to 2, becomes special as we turn on SM.

10. Could Lightning Strike Twice? From a simple UV theory to rich IR Physics Turn on hyperfermions charged under SM. SM breaks many of the flavor numbers, introduce “species” of hyperfermions. (e.g. color triplet) Changes running of SM couplings, for one species in to avoid QCD Landau-pole in the UV. interpolated bycan mix with SM gauge bosons, resonant production. charges. Radiative masses for Anomaly of can decay with zero species number ( - short) Species number unbroken. Leads to stable.

11. Could Lightning Strike Twice? From a simple UV theory to rich IR Physics - long stable, SM charged. UV physics analogous to weak interactions can decay them to non- hypercolored particles (SM). or breaks species numbers. Straightforward to break hyperbaryon number as well. Model dependent. Models constrained, there must exist a SM final state with matching quantum numbers. (simple choice: GUT-like representations)

12. Constraints (I) Vectorlike fermions: Confinement preserves vector part of flavor symmetry, SM unaffected. Choose quantum numbers such that Yukawa terms with the SM Higgs forbidden, PEW safe. “Gauge mediation” means that flavor violating effects from renormalizable part of the VC theory suppressed relative to the SM by loop factor. Nonrenormalizable operators can induce flavor violating SM operators. For generic coefficients, need M ~ O(10 4 ) TeV. For special flavor structure, M can be anything consistent with EFT description.

13. Phenomenological Lagrangian The Not literal EFT. Large N estimates. Mixing/production: where Shiftinduces Production from gluons Dominant decay fromwhere Rare decays

14. Phenomenological Lagrangian Masses Three sources of mass: SM gauge groups break the flavor symmetry Fundamental hyperquark masses From EWSB

15. Phenomenological Lagrangian -short and -long Chiral anomalies induce those with no net species numbers decay to a pair of gauge bosons. Here Higher dimensional operators decay with nonzero species number.

16. Phenomenological Lagrangian -long Decay Length Current-current decays suppressed by fermion masses Scalar-scalar decays are less suppressed Prospects for visibility tied to flavor structure.

17. Phenomenological Lagrangian Overview

18. Constraints (II) Many exotic states with SM charges. Ocean bottom searches for charged particles: Plenty of room between bounds from cosmology and flavor. Fermion compositeness: worst case is eeqq, OK as long as -short decays at the Tevatron OK as long as Resonant production and decay to SM: electroweak has too small cross section/branching fraction, color is interesting – search strategy in a few slides. Singlet are axions. For we have (safe for SN cooling, beam dump) decay not observable not observable (BF too small)

19. A Few Simple Models SU(2) Doublet representation Spectrum contains with, bleak collider phenomenology There is a special that could keep the from decaying because axial current is odd: MDM candidate? If decays, adding a singlet gives more generic structure, without losing any features.

20. A Few Simple Models What a Singlet Can Do SM charge assignment: The singlet as “strange” Masses (singlet is axion): After EWSB: -strahlung at LEP?

21. A Few Simple Models What a Singlet Can Do Resonances: Short-lived pions: Lepton-rich, very good reconstruction in the channel. Long lived pions decays through the current operator (heavier states preferred). When suppression scale is low, prompt or displaced same- sign tau-pair +MET as well as, otherwise CHAMP pairs. too soft to see

22. Triggers like a muon. Experimental handles: curvature, dE/dx,ToF Tevatron Limits dictate Distributions more advanced analysis by Chen & Adams (200 pb -1 at 10 TeV) A Few Simple Models CHAMPs

23. Associated production givesmode.(BF ~35% in CN) Resonant as well as nonresonant channels. (~65% in CC) (GMSB searches) – work in progress. (~32% in CN) Distributions Hyperbaryon decay A Few Simple Models Multi-photons

24. A Few Simple Models SU(3) Triplet Color triplet gives rise to color octet,. Without any electroweak charges, can be as light as 300GeV. Possibly in Tevatron data, not excluded, discoverable. still easy at LHC, harder.

25. A Few Simple Models SU(3) Triplet + Singlet Add a singlet Spectrum Decay modes Axion mode interesting but unobservable

26. A Few Simple Models R-Hadrons Triplet collider stable or decays through current- current operator, 3 rd generation leptoquark R-hadrons will be charged with O(1) probability. Resonance easier to observe compared to EW model. 4 R-hadrons (leptoquarks) if g’ pair produced – fb cross section Hyperbaryon decay

27. A Few Simple Models Spectators DM candidates generic in VC models. Exotic species have a much harder time decaying and make up DM candidate can decay to “Squark” pair production with subsequent decay to “LSP” More general cascades

28. Conclusions VC: New confining gauge interactions with vectorlike matter are theoretically simple and generic. “Gauge-mediated” setup with vectorlike matter ensures safety from low energy precision tests. Vector states can be resonantly produced, decay to naturally light PGB’s. Scalars have short-lived and collider stable species. –Short-lived scalars decay to a pair of SM gauge bosons. 4 GB final states can be spectacular. –Long lived scalars appear as CHAMPs / R-hadrons. Resonance reconstruction possible. Decays into heavy flavors can be preferred. (leptoquarks, di-taus, di-tops…) Unbroken species number or spectators can give DM candidates. Cascades possible.