1. Minimal Electroweak Scale Cosmology and the LHC M.J. Ramsey-Musolf Wisconsin-Madison http://www.physics.wisc.edu/groups/particle-theory/ NPAC Theoretical Nuclear, Particle, Astrophysics & Cosmology Berkeley, March 2009

2. Outline I.Intro & Motivation II.Baryogenesis & EWPT III.Three minimal models & their LHC phenomenology Real Singlet xSM Complex SingletcxSM Real Triplet  SM V. Barger, P. Fileviez Perez, H. Patel, P. Langacker, M. McCaskey, D. O.Connell, S. Profumo, G. Shaugnessy, K. Wang, M. Wise Minimal TeV-scale SM extensions Can help explain the origin of matter (visible and dark) Can be discovered at the LHC Can be probed in cosmologically relevant parameter space at colliders

3. Cosmology at the HEP & NP Interface Nature of DM & its interactions Origin of the BAU Two puzzles: Additional problems: Gauge hierarchy EWPO & m H (little hierarchy) Origin of m Indirect & direct detection Collider E Collider: EWPT & spectrum EDM: CPV

4. Non-minimal Solutions (SUSY) Nature of DM & its interactions Origin of the BAU Gauge hierarchy EWPO & m H Origin of m “Minimal” : 105 new parameters        Additional complications: Why is  ~ M weak ? Why little flavor & CPV ? Origin of params in L soft ? M SUSY < TeV (hierarchy) Bino-Higgsino-like LSP (DM) Light RH stop ( m < 125 GeV) M 1 ~     

5. Minimal Solutions (non-SUSY) Nature of DM & its interactions Origin of the BAU Gauge hierarchy EWPO & m H Origin of m      Extra ScalarsExtra Fermions     

6. Set aside hierarchy problem (for now) To what extent can minimal scenarios for new electroweak scale physics help explain the abundance of matter (visible & dark) ? How can they be probed at the LHC ? This Talk

7. Highlight for This Talk: Scalars Gauge Interactions No Gauge Interactions Simplest: 1 new dof Next Simplest: 2 new dof Focus: Key parameters for cosmo & LHC pheno Complex Singlet (cxSM): DM, BAU, and m H / EWPO H-S Mixing, Reduced BRs, &  SI Real Singlet (xSM): DM or BAU-m H / EWPO BAU: H-S Mixing & Reduced BRs DM: Reduced BRs &  SI Simplest: 3 new dof (2HDM: 4 new dof) Real Triplet  SM)  DM or BAU (EWPT) DM: Charged track &  SI BAU:  or bb  ;  Br(H!  )

8. Baryogenesis: Ingredients Anomalous B-violating processesPrevent washout by inverse processes Sakharov Criteria B violation C & CP violation Nonequilibrium dynamics Sakharov, 1967 SM Sphalerons:  SM CKM CPV:  SM EWPT:  EDMs LHC: Scalars

9. Electroweak Phase Transition & Higgs 1st order2nd order LEP EWWG Increasing m h m h >114.4 GeV or ~ 90 GeV (SUSY) Computed E SM : m H < 70 GeV Need So that  sphaleron is not too fast E MSSM ~ 10 E pert SM : m H < 120 GeV Stop loops in V Eff Light RH stop w/ special Non-doublet Higgs (w / wo SUSY) MixingDecay

10. The Simplest Extension Model Independent Parameters: v 0, x 0, 0, a 1, a 2, b 3, b 4 H-S Mixing H 1 ! H 2 H 2 Mass matrix Stable S (dark matter?) Tree-level Z 2 symmetry: a 1 =b 3 =0 to prevent s-h mixing and one-loop s hh x 0 =0 to prevent h-s mixing xSM EWPT:  Signal Reduction Factor ProductionDecay sin 2  Simplest extension of the SM scalar sector: add one real scalar S Goal: identify generic features of minimal models with new scalars having a strong, 1 st order EWPT and/or DM Determine low-energy phenomenology (Higgs studies, precision ewk) Address CPV with a different mechanism

11. Finite Temperature Potential What is the pattern of symmetry breaking ? What are conditions on the couplings in V(H,S) so that /T > 1 at T C ? Cylindrical Co-ordinates Compute V eff (  T ) Minimize w.r.t  Find T C Evaluate v(T C )/T C ~ cos  (T C )  (T C )/T C

12. V EFF (T) & EWSB Potential Key Parameters Analytic Numerical Strong first order EWPT: SM Strong first order EWPT Increase  Large e < 0 Reduce Nonzero V 0 a 1 <0, a 2 either sign Light: all models Black: LEP allowed a 1 =b 3 = 0, a 2 < 0

13. Symmetry Breaking Two Cases for at high T: V min = 0 V min = V 0 < 0

14. LHC Phenomenology Signatures EWPO compatible m 2 > 2 m 1 m 1 > 2 m 2 LHC: reduced BR(h SM) Signal Reduction Factor ProductionDecay CMS 30 fb -1  SM-like Singlet-like SM-like SM-like w/ H 2 ->H 1 H 1 or Singlet-like ~ EWB Viable Light: all models Black: LEP allowed Scan: EWPT-viable model parameters LHC exotic final states: 4b-jets,  + 2 b-jets… EWPO comp w/ a 1 =0=b 3 LHC: reduced BR(h SM) Probing   : WBF H ! ZZ! 4 l H ! WW! 2j l Early LHC discovery possible Determine  as low as ~ 0.5

15. Complex Singlet: EWB & DM Barger, Langacker, McCaskey, R-M, Shaugnessy: 0811.0393 [hep-ph] Key features for EWPT & DM: (1)Softly broken global U(1) (2)Closes under renormalization (3)SSB leading to two fields: S that mixes w/ h and A is stable (DM) Controls  CDM & EWPT No domain walls DM mass No CPV for T < T EW : Stable A Spontaneous CPV for T ~ T EW ?

16. Complex Singlet: EWB & DM Barger, Langacker, McCaskey, R-M, Shaugnessy  2 controls  CDM & EWPT M H1 = 120 GeV, M H2 =250 GeV, x 0 =100 GeV

17. Complex Singlet: Direct Detection Barger, Langacker, McCaskey, R-M, Shaugnessy Two component case (x 0 =0) Little sensitivity of scaled  SI to  

18. Complex Singlet: LHC Discovery Barger, Langacker, McCaskey, R-M, Shaugnessy Traditional search: CMSInvisible search: ATLAS Single component case (x 0 = 0) EWPT

19. VBF: Invisible Search I Central Jet Veto H ! W + W - !  jj : ideally only W decay products in central region (Chehime & Zeppenfeld ‘93)  H ! W + W - ! l + l -  : central region minijet from SM bcknd,  separation from dilepton pair (Barger, Phillips, Zeppenfeld ‘94)

20. VBF: Invisible Search II p T (H) distribution  Look for azimuthal shape change of primary jets (Eboli & Zeppenfeld ‘00) Large p T (invisible decay) Dijet azimuthal distribution  Cahn et al ‘87

21. Complex Singlet: LHC Discovery Barger, Langacker, McCaskey, R-M, Shaugnessy Traditional search: CMSInvisible search: ATLAS Single component case (x 0 = 0) EWPT Combined search

22. Real Triplet       ~ ( 1, 3, 0 ) H 1 -> H 2 H 2 H-  Mixing Independent Parameters: v 0, x 0, 0, a 1, a 2, b 4 Fileviez-Perez, Patel, Wang, R-M: 0811.3957 [hep-ph]

23. Real Triplet : Key Features  Gauge interactions  Large     ! W + W - : Need M  ~ 2 TeV for full  CDM  parameter Small x 0 (T=0) : Small mixing & EWPO impact “Fermiophobic” 1st order EWPT ? Spectrum Four scalars : H 1 ~ SM-like; H 2 ~ triplet-like; H +, H - Couplings & 2  BRs H 1 H + H - & H 2 W + W - : Strong a 2 -dependence ! Sensitivity of BR(H j !  )

24. Real Triplet : Production Pair production dominant Assoc production     suppressed Below WZ Threshold Promising for LHC Promising for ILC Above WZ Threshold

25. Real Triplet : H + Decays Charged: decay length Secondary vertex Tiny x 0 : pure gauge DM Limit: x 0 =0 & c  = 5.06 cm

26. Real Triplet : DM Search Basic signature: Charged track disappearing after ~ 5 cm SM Background: QCD jZ and jW w/ Z !  & W!l Trigger: Monojet (ISR) + large E T Cuts: large E T hard jet One 5cm track Cirelli et al: M  = 500 GeV:    CDM ~ 0.1

27. Real Triplet : Charged BRs I Charged: x 0 dependence Pure gauge x 0 suppressed

28. Real Triplet : Charged BRs II Charged: x 0 dependence Below WZ Threshold Above WZ Threshold Pure gauge x 0 supressed

29. Real Triplet : General Search I Cuts: min p T (  )> 25 GeV max p T (  )> 50 GeV |  | 0.4 Basic signature:  (large x 0 ) or  b b (small x 0 ) | M  - M H2 | < 5 GeV Identification: For bb: b-tagging, p T (b)> 15 GeV, |  (b)| < 3.0 For  soft  from hadronic decay ! Leptonic decay w/ 5 GeV 20 GeV, edge of M T

30. Real Triplet : General Search II Basic signature:  or  b b a 2 = 1, 0, -1 : Small x 0 : Large x 0 : a 2 -dependence of H 2 W + W - coupling

31. Real Triplet : Couplings H 2 WW Coupling H 1 H + H - Coupling:  (H 1 !  ) depends on a 2 via H + H - loops  (H 2 !  ) depends on a 2 via W + W - loops

32. Real Triplet : Neutral BRs Neutral: differences with SM Higgs & a 2 dependence Different ratio of WW and ZZ,  BRs

33. Real Triplet : H 1 Decays Neutral SM-like Higgs: H + loops and BR ( H 1 !  ) X 0 =0: DM caseX 0 >0: EWPT case

34. Real Triplet : Summary Parameters relevant for EWPT: x 0, a 1, a 2 H + mass & decays: x 0, a 1 H 1,2 WW coupling via  : a 2 DM Search: ~ 50 events for    CDM ~ 0.1 (M  ~ 500 GeV); study BR(H 1 !  )

35. Summary Gauge Interactions No Gauge Interactions Simplest: 1 new dof Next Simplest: 2 new dof Complex Singlet (cxSM): DM, BAU, and m H / EWPO H-S Mixing, Reduced BRs, &  SI Real Singlet (xSM): DM or BAU-m H / EWPO BAU: H-S Mixing & Reduced BRs DM: Reduced BRs &  SI Simplest: 3 new dof (2HDM: 4 new dof) Real Triplet  SM)  DM or BAU (EWPT) DM: Charged track &  SI BAU:  or bb  ;  Br(H!  ) Minimal TeV-scale SM extensions Can help explain the origin of matter (visible and dark) Can be discovered at the LHC Can be probed in cosmologically relevant parameter space at colliders