1 / 35

Minimal Electroweak Scale Cosmology and the LHC

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

isha
Download Presentation

Minimal Electroweak Scale Cosmology and the LHC

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

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

  2. 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 V. Barger, P. Fileviez Perez, H. Patel, P. Langacker, M. McCaskey, D. O.Connell, S. Profumo, G. Shaugnessy, K. Wang, M. Wise Outline Intro & Motivation Baryogenesis & EWPT Three minimal models & their LHC phenomenology • Real Singlet xSM • Complex Singlet cxSM • Real Triplet SM

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

  4.   • MSUSY < TeV (hierarchy) • Bino-Higgsino-like LSP (DM) • Light RH stop ( m < 125 GeV) • M1 ~  •      Additional complications: • Why is ~ Mweak ? • Why little flavor & CPV ? • Origin of params in Lsoft ? Non-minimal Solutions (SUSY) “Minimal” : 105 new parameters Nature of DM & its interactions Origin of the BAU Gauge hierarchy EWPO & mH Origin of m

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

  6. This Talk • 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 ?

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

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

  9. Light RH stop w/ special Need 1st order 2nd order Non-doublet Higgs (w / wo SUSY) So that Gsphaleron is not too fast Mixing Decay Increasing mh Computed ESM: mH < 70 GeV Stop loops in VEff mh>114.4 GeV EMSSM ~ 10 EpertSM :mH < 120 GeV or ~ 90 GeV (SUSY) Electroweak Phase Transition & Higgs LEP EWWG

  10. Stable S (dark matter?) • Tree-level Z2 symmetry: a1=b3=0 to prevent s-h mixing and one-loop s hh • x0 =0 to prevent h-s mixing sin2q Mass matrix Simplest extension of the SM scalar sector: add one real scalar S H-S Mixing H1 !H2H2 • Goal: identify generic features of minimal models with new scalars having a strong, 1st order EWPT and/or DM • Determine low-energy phenomenology (Higgs studies, precision ewk) • Address CPV with a different mechanism Signal Reduction Factor Independent Parameters: v0, x0, l0, a1, a2, b3, b4 xSM EWPT:  Production Decay The Simplest Extension Model

  11. What is the pattern of symmetry breaking ? • What are conditions on the couplings in V(H,S) so that <H0>/T > 1 at TC ? • Compute Veff ( f, a, T ) • Minimize w.r.t f , a • Find TC • Evaluate v(TC )/TC ~ cos a(TC) f(TC )/TC CylindricalCo-ordinates Finite Temperature Potential

  12. Strong first order EWPT Strong first order EWPT: SM Increase e Large e < 0 Reduce l Nonzero V0 Light: all models Black: LEP allowed Analytic Numerical a1<0, a2 either sign a1=b3= 0, a2 < 0 Analytic VEFF (T) & EWSB Potential Key Parameters

  13. Symmetry Breaking Two Cases for <S>at high T: Vmin = 0 Vmin = V0 < 0

  14. EWPO comp w/ a1=0=b3 EWPO compatible LHC exotic final states: 4b-jets, gg + 2 b-jets… SM-like SM-like w/ H2 ->H1H1 or Singlet-like SM-like Singlet-like Probing  : WBF Light: all models Black: LEP allowed LHC: reduced BR(h SM) LHC: reduced BR(h SM) Scan: EWPT-viable model parameters H ! ZZ! 4 l m2 > 2 m1 m1 > 2 m2 H ! WW! 2j l  • EarlyLHC discovery possible • Determine as low as ~ 0.5 ~ EWB Viable Signal Reduction Factor Production Decay CMS 30 fb-1 LHC Phenomenology Signatures

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

  16. Complex Singlet: EWB & DM Barger, Langacker, McCaskey, R-M, Shaugnessy 2 controls CDM& EWPT MH1 = 120 GeV, MH2=250 GeV, x0=100 GeV

  17. Complex Singlet: Direct Detection Barger, Langacker, McCaskey, R-M, Shaugnessy Two component case (x0=0) Little sensitivity of scaled SI to 

  18. Single component case (x0 = 0) EWPT Complex Singlet: LHC Discovery Barger, Langacker, McCaskey, R-M, Shaugnessy Traditional search: CMS Invisible search: ATLAS

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

  21. Single component case (x0 = 0) EWPT Combined search Complex Singlet: LHC Discovery Barger, Langacker, McCaskey, R-M, Shaugnessy Traditional search: CMS Invisible search: ATLAS

  22. S0 , S+, S- Independent Parameters: v0, x0, l0, a1, a2, b4 H- Mixing H1 -> H2H2 Real Triplet Fileviez-Perez, Patel, Wang, R-M: 0811.3957 [hep-ph] ~ ( 1, 3, 0 )

  23. Gauge interactions Large ! W+W- : Need M ~ 2 TeV for full CDM parameter Small x0(T=0): Small mixing & EWPO impact “Fermiophobic” 1st order EWPT ? Spectrum Four scalars: H1 ~ SM-like; H2 ~ triplet-like; H+, H- Couplings & 2BRs H1H+H- & H2W+W- : Strong a2-dependence ! Sensitivity of BR(Hj!) Real Triplet : Key Features

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

  25. Secondary vertex DM Limit: x0=0 & c = 5.06 cm Tiny x0 : pure gauge Real Triplet : H+ Decays Charged: decay length

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

  27. Pure gauge x0 suppressed Real Triplet : Charged BRs I Charged: x0 dependence

  28. Pure gauge x0 supressed Real Triplet : Charged BRs II Charged: x0 dependence Below WZ Threshold Above WZ Threshold

  29. Basic signature: (large x0) or b b (small x0) Identification: For bb: b-tagging, pT(b)> 15 GeV, |(b)| < 3.0 For soft from hadronic decay ! Leptonic decay w/ 5 GeV < pT(l) < 40 GeV, |(l)| < 2.8, ET > 20 GeV, edge of MT Real Triplet : General Search I Cuts: min pT()> 25 GeV max pT()> 50 GeV | | < 2.8 R > 0.4 |M - MH2| < 5 GeV

  30. Basic signature: or b b Small x0 : Large x0 : Real Triplet : General Search II a2 = 1, 0, -1 : a2-dependence of H2W+W- coupling

  31. Real Triplet : Couplings H2 WW Coupling (H2!) depends on a2 via W+W- loops H1 H+ H- Coupling: (H1!) depends on a2 via H+H- loops

  32. Real Triplet : Neutral BRs Neutral: differences with SM Higgs & a2 dependence Different ratio of WW and ZZ,  BRs

  33. Real Triplet : H1 Decays Neutral SM-like Higgs: H+ loops and BR ( H1!) X0=0: DM case X0>0: EWPT case

  34. Real Triplet : Summary Parameters relevant for EWPT: x0 , a1 , a2 H+ mass & decays: x0 , a1 H1,2WW coupling via : a2 DM Search: ~ 50 events for CDM ~ 0.1 (M ~ 500 GeV); study BR(H1!)

  35. Real Singlet (xSM): • 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 DM or BAU-mH / EWPO BAU: H-S Mixing & Reduced BRs DM: Reduced BRs & SI Complex Singlet (cxSM): DM, BAU, and mH / EWPO H-S Mixing, Reduced BRs, & SI Real Triplet (SM): DM or BAU (EWPT) DM: Charged track & SI BAU: or bb; Br(H!) Summary No Gauge Interactions Simplest: 1 new dof Next Simplest: 2 new dof Gauge Interactions Simplest: 3 new dof (2HDM: 4 new dof)

More Related