Electroweak Phase Transition, Scalar Dark Matter, & the LHC. M.J. Ramsey-Musolf

Transcription

1 Electroweak Phase Transition, Scalar Dark Matter, & the LHC M.J. Ramsey-Musolf Wisconsin-Madison NPAC Theoretical Nuclear, Particle, Astrophysics & Cosmology ANL Seminar, February 2012

2 Recent Work M. Gonderinger, Y. Li, H. Patel, & MRM, arxiv: M. Buckley & MRM JHEP 1109 (2011) 094 H. Patel & MRM, JHEP 1107 (2011) 029 C. Wainwright, S. Profumo, MRM Phys Rev. D84 (2011) M. Gonderinger, H. Lim, & MRM, arxiv:

3 Scalar Fields in Cosmology What role do scalar fields play (if any) in the physics of the early universe?

4 Scalar Fields in Particle Physics Scalar fields are a simple Scalar fields are theoretically problematic " NEW Δ m 2 ~ λ Λ 2 H 0 H 0 Fundamental scalars have yet to be observed

5 Scalar Fields in Cosmology Problem Theory Exp t Inflation Dark Energy Dark Matter Phase transitions

6 Scalar Fields & Cosmic History New Scalars? EW Symmetry Breaking: Higgs? Standard Model Universe QCD: q+g! n,p QCD: n+p! nuclei Astro: stars, galaxies,..

7 Scalar Fields & Inflation EW Symmetry Breaking: Higgs? New Scalars? Standard Model Universe Flatness Isotropy Homogeneity Scalar Field: Inflaton Reheat Slow roll QCD: q+g! n,p QCD: n+p! nuclei Astro: stars, galaxies,..

8 Scalar Fields & Dark Energy? ΛCDM Supernovae BAO Cosmological constant? > 0 Scalar Field: Quintessence?

9 Scalar Fields & the Origin of Matter? Baryogenesis: When? CPV? SUSY? Neutrinos? Non-equilibrium dynamics or CPT violation? BBN ( t ~ 100 s ) CMB ( t ~ 10 5 y )

10 Scalar Fields & the Origin of Matter? Electroweak Phase Transition? New Scalars Baryogenesis: When? CPV? SUSY? Neutrinos? Non-equilibrium dynamics or CPT violation? BBN ( t ~ 100 s ) CMB ( t ~ 10 5 y )

11 Scalar Fields & the Origin of Matter?? Electroweak Phase Transition? New Scalars Baryogenesis: When? CPV? SUSY? Neutrinos? Non-equilibrium dynamics or CPT violation? Rotation curves Lensing Bullet clusters Darkogenesis: When? SUSY? Neutrinos? Axions? Y B related?

12 Scalar Fields & the Origin of Matter?? Electroweak Phase Transition? New Scalars: CDM? Baryogenesis: When? CPV? SUSY? Neutrinos? Non-equilibrium dynamics or CPT violation? Rotation curves Lensing Bullet clusters Darkogenesis: When? SUSY? Neutrinos? Axions? Y B related?

13 Scalar Fields in Cosmology Problem Theory Exp t Inflation Dark Energy Dark Matter Phase transitions????

14 Scalar Fields in Cosmology Problem Theory Exp t Inflation Dark Energy Dark Matter Phase transitions???? Could experimental discovery of a fundamental scalar point to early universe scalar field dynamics?

15 Scalar Fields in Cosmology Problem Theory Exp t Inflation Dark Energy Dark Matter Phase transitions???? Focus of this talk, but perhaps part of larger role of scalar fields in early universe

16 Questions for this Talk: Was there a cosmic phase transition at T ~ 100 GeV? Did it have the characteristics needed for successful electroweak baryogenesis and/or production of gravity waves? Are its dynamics coupled to dark matter? What are the experimental signatures? How robust is the underlying theory?

17 Outline I. EWPT: General Features II. Three minimal extensions of the Standard Model scalar sector III. How will we know it s a scalar? IV. Theoretical issues

18 I. General Features

19 Effective Potential * Tree level L = (D µ ϕ ) (D µ ϕ) - V(ϕ ) Quantum corrections V(ϕ ) ) V EFF (ϕ,t) T=0 : Coleman-Weinberg (RG improved) T>0 : Finite-T effective potential * Many applications: Effective action

20 EW Phase Transition: New Scalars F 1st order F 2nd order!! Increasing m h New scalars

21 EW Phase Transition: New Scalars F 1st order F 2nd order!! Increasing m h Baryogenesis Gravity Waves Scalar DM LHC Searches New scalars

22 EW Phase Transition: New Scalars F 1st order F 2nd order Strong 1 st order EWPT!! Increasing m h Baryogenesis Gravity Waves Scalar DM LHC Searches New scalars

23 EW Phase Transition: New Scalars F 1st order F 2nd order Strong 1 st order EWPT!! Bubble nucleation Increasing m h New scalars Baryogenesis Gravity Waves Scalar DM LHC Searches EWSB

24 EW Phase Transition: New Scalars F 1st order F 2nd order Strong 1 st order EWPT!! Bubble nucleation Increasing m h Baryogenesis Gravity Waves Scalar DM LHC Searches New scalars Y B : CPV & EW sphalerons EWSB A "

25 EW Phase Transition: New Scalars F 1st order F 2nd order Strong 1 st order EWPT!! Bubble nucleation Increasing m h Baryogenesis Gravity Waves Scalar DM LHC Searches New scalars Y B : diffuses into interiors EWSB A "

26 EW Phase Transition: New Scalars F 1st order F 2nd order Strong 1 st order EWPT Increasing m h Baryogenesis Gravity Waves Scalar DM LHC Searches!! New scalars Preserve Y B initial Quench EW sph Y B : diffuses into interiors Bubble nucleation EWSB A "

27 EW Phase Transition: New Scalars F 1st order F 2nd order Strong 1 st order EWPT Increasing m h Baryogenesis Gravity Waves Scalar DM LHC Searches!! New scalars Preserve Y B initial Quench EW sph Y B : diffuses into interiors T C, E sph, S tunnel Bubble nucleation EWSB F(φ)

28 EW Phase Transition: New Scalars F 1st order F 2nd order Strong 1 st order EWPT!! Detonation & turbulence Bubble nucleation Increasing m h Baryogenesis Gravity Waves Scalar DM LHC Searches New scalars EWSB

29 EW Phase Transition: New Scalars F 1st order F 2nd order Strong 1 st order EWPT!! Detonation & turbulence Bubble nucleation Increasing m h Baryogenesis Gravity Waves Scalar DM LHC Searches New scalars GW Spectra: ΔQ & Δt EW EWSB F(φ)

30 EW Phase Transition: New Scalars F 1st order F 2nd order Strong 1 st order EWPT!! Detonation & turbulence Bubble nucleation Increasing m h nmssm New scalars Baryogenesis ΔQ Gravity Waves Scalar DM LHC Searches Δt EW GW Spectra: ΔQ & Δt EW EWSB F(φ)

31 EW Phase Transition: New Scalars F 1st order F 2nd order Strong 1 st order EWPT!! Y B preservation, detonation & turbulence Bubble nucleation Increasing m h New scalars Baryogenesis Gravity Waves Scalar DM? LHC Searches? T C, E sph, S tunnel ΔQ & Δt EW EWSB F(φ)

32 Higgs Boson Searches SM Higgs?

33 SM Higgs? LHC Indications LHC Exclusion Tevatron SM background Excl well below new CPV expectations New expts: 10 2 to 10 3 more sensitive CPV needed for BAU? LEP Exclusion Non-SM Higgs(es)? Precision Tests SM Higgs properties?

34 Dark Matter: Ω χ & σ SI Thermal DM: WIMP Direct detection: Spin-indep DM-nucleus scattering χ SM χ A χ SM χ A

35 II. Simplest Scalar Extensions Extension DOF EWPT DM Real singlet Real singlet Complex Singlet Real Triplet ? May be low-energy remnants of UV complete theory & illustrative of generic features

36 The Simplest Extension ModelSimplest Signal extension Reduction of the Factor SM scalar Tree-level sector: Z 2 symmetry: add one a 1 real =b 3 =0 scalar to S (SM singlet) Stable S (dark matter?) H-S Mixing prevent s-h mixing and one-loop s Mass matrix " M 2 = $ # 2 µ hs 2% " h 1 % 2 ' $ 2 µ s & # h 2 & ' = " $ sin( / # cos( / Independent Parameters: µ h 2 2 µ hs v 0, x 0, λ 0, a 1, a 2, b 3, b 4 hh x 0 =0 to prevent h-s mixing xsm EWPT: Production Decay EWPT: a 1,2 = 0 & <S> = 0 DM: a 1 = 0 & <S> = 0 cos( % )sin(& ' " $ h% # s ' & H 1! H 2 H 2 O Connel, R-M, Wise; Profumo, R-M, Shaugnessy; Barger, Langacker, McCaskey, R-M Shaugnessy; He, Li, Li, Tandean, Tsai; Petraki & Kusenko; Gonderinger, Li, Patel, R-M; Cline, Laporte, Yamashita; Ham, Jeong, Oh; Espinosa, Quiros; Konstandin & Ashoorioon

37 The Simplest Extension Model Stable S (dark matter?) Signal Reduction Factor EWPT Scenario Tree-level Z H-S Mixing 2 symmetry: a 1 =b 3 =0 to prevent s-h mixing and one-loop s hh H 1! H 2 H 2 x 0 =0 to prevent h-s mixing xsm EWPT: Production Decay Mass matrix 2 2 Raise " µ barrier M 2 = h µ hs 2% " h 1 % $ 2 2 ' $ # µ hs 2 µ s & # h 2 & ' = " sin( Lower cos( T % $ # cos( )sin(& ' " $ h% C : a s ' 2 < 0 # & Independent Parameters: v 0, x 0, λ 0, a 1, a 2, b 3, b 4

38 Finite Temperature Potential H 0 F F Multiple fields & new interactions: novel patters of symmetry breaking, lower T C, greater super-cooling, stronger 1 st order EWPT S!! F F H 0 S!!

39 The Simplest Extension Model Stable S (dark matter?) Signal Low energy Reduction phenomenology Factor Tree-level Z H-S Mixing 2 symmetry: a 1 =b 3 =0 to prevent s-h mixing and one-loop s hh H 1! H 2 H 2 x 0 =0 to prevent h-s mixing xsm EWPT: Production Decay Mass matrix 2 2 Raise " µ barrier M 2 = h µ hs 2% " h 1 % $ 2 2 ' $ # µ hs 2 µ s & # h 2 & ' = " sin( Lower cos( T % $ # cos( )sin(& ' " $ h% C s ' # & Independent Parameters: Mixingv 0, x 0, λ 0, a 1, a 2, b 3, b Modified BRs 4 Two mixed (singlet-doublet) states w/ reduced SM branching ratios

40 EWPT & LHC Phenomenology Signatures m 2 > 2 m 1 b LHC exotic final Scan: EWPT-viable h 1 h b states: 2 4b-jets, γ " model parameters h 1 γ + 2 b-jets " Light: all models Black: LEP allowed LHC: reduced h 2 BR(h SM) h 1 h 2 m 1 > 2 m 2 Signal Reduction Factor Profumo, R-M, Shaugnessy Production Decay

41 EWPT & LHC Phenomenology Signatures m 2 > 2 m 1 LHC exotic final Scan: EWPT-viable states: 4b-jets, γ model parameters γ + 2 b-jets Light: all models Black: LEP allowed LHC: reduced BR(h SM) m 1 > 2 m 2 Signal Reduction Factor Profumo, R-M, Shaugnessy Production Decay

42 EWPT & LHC Phenomenology Signatures LHC exotic final Scan: EWPT-viable states: 4b-jets, γ model parameters γ + 2 b-jets m 2 > 2 m 1 EWPO compatible Scan: EWPT-viable model parameters Light: all models Black: LEP allowed LHC: reduced BR(h SM) m 1 > 2 m 2 Signal Reduction Factor Profumo, R-M, Shaugnessy Production Decay

43 EWPT & LHC Phenomenology Signatures m 2 > 2 m 1 LHC exotic final Scan: EWPT-viable states: 4b-jets, γ model parameters γ + 2 b-jets EWPO compatible EWPO comp w/ a 1 =0=b 3 Light: all models Black: LEP allowed LHC: reduced BR(h SM) m 1 > 2 m 2 LHC: reduced BR(h SM) Signal Reduction Factor Profumo, R-M, Shaugnessy Production Decay

44 EWPT & LHC Phenomenology Signatures m 2 > 2 m 1 LHC exotic final Scan: EWPT-viable states: 4b-jets, γ model parameters γ + 2 b-jets EWPO compatible EWPO comp w/ a 1 =0=b 3 Light: all models Black: LEP allowed LHC: reduced BR(h SM) m 1 > 2 m 2 LHC: reduced BR(h SM) SM-like Signal Reduction Factor SM-like Singlet-like Barger, Langacker, McCaskey, R-M, Shaugnessy Production Decay CMS 30 fb -1 SM-like w/ H 2 ->H 1 H 1 or Singlet-like

45 The Simplest Extension Model Stable S (dark matter?) Signal Reduction Factor DM Scenario Tree-level Z H-S Mixing 2 symmetry: a 1 =b 3 =0 to prevent s-h mixing and one-loop s hh H 1! H 2 H 2 x 0 =0 to prevent h-s mixing xsm EWPT: Production Decay Mass matrix " M 2 = $ # 2 µ hs 2% " h 1 % 2 ' $ 2 µ s & # h 2 & ' = " sin( Ω cos( % $ # cos( )sin(& ' " $ h% DM & σ SI # s ' & Independent Parameters: µ h 2 2 µ hs v 0, x 0, λ 0, a 1, a 2, b 3, b 4 + +

46 DM Phenomenology Relic Density He, Li, Li, Tandean, Tsai Direct Detection Barger, Langacker, McCaskey, R-M, Shaugnessy He, Li, Li, Tandean, Tsai

47 Vacuum Stability & Perturbativity Preserving EW Min Funnel plot V EFF EW vacuum top loops perturbativity naïve stability scale Λ ϕ m H? DM-H coupling top loops Gonderinger, Li, Patel, R-M

48 Vacuum Stability & Perturbativity Preserving EW Min Funnel plot V EFF EW vacuum top loops perturbativity naïve stability scale Λ ϕ m H? m S 2 = b 2 + a 2 v 2 Z 2 -breaking vacuum s ϕ Gonderinger, Li, Patel, R-M Z 2 -preserving EW vacuum No DM: Z 2 -breaking vac

49 LHC & Higgs Phenomenology Invisible decays LHC discovery potential He, Li, Li, Tandean, Tsai Signal Reduction Factor Production Decay Dijet azimuthal distribution h j A A Look for azimuthal shape change of primary jets (Eboli & Zeppenfeld 00)

50 LHC & Higgs Phenomenology Invisible decays LHC discovery potential He, Li, Li, Tandean, Tsai Signal Reduction Factor Production Decay Dijet azimuthal distribution h j Γ (h!ss)=0 A A Invis search Look for azimuthal shape change of primary jets (Eboli & Zeppenfeld 00)

51 Complex Singlet: EWB & DM? Barger, Langacker, McCaskey, R-M Shaugnessy Spontaneously & softly broken global U(1) Controls Ω CDM, T C, & H-S mixing Gives non-zero M A

52 Complex Singlet: EWB & DM Barger, Langacker, McCaskey, R-M, Shaugnessy δ 2 controls Ω CDM & EWPT decreasing T C M H1 = 120 GeV, M H2 =250 GeV, x 0 =100 GeV

53 Complex Singlet: Direct Detection Barger, Langacker, McCaskey, R-M, Shaugnessy Two component case (x 0 =0) Little sensitivity of scaled σ SI to δ 2

54 SM Higgs? SM Branching Ratios? h j D D EWPT He et al Barger, Langacker, McCaskey, RM, Shaugnessy h j D Three scalars: h 1,2 (Higgs-like) D (dark matter) D LHC: WBF Invisible decay search

55 SM Higgs? SM Branching Ratios? h j D D Viable Dark Matter? 2 nd light state Ω TH < Ω WMAP σ < σ Xenon Br(inv) > 0.6 EWPT He et al Barger, Langacker, McCaskey, RM, Shaugnessy WIMP-Nucleus Scattering Gonderinger, Lim, R-M h j D Three scalars: h 1,2 (Higgs-like) D (dark matter) D LHC: WBF Invisible decay search

56 Real Triplet Σ 0, Σ +, Σ ~ ( 1, 3, 0 ) Fileviez-Perez, Patel, Wang, R-M: PRD 79: (2009); [hep-ph] EWPT: a 1,2 = / 0 & <Σ 0 > = / 0 DM & EWPT: a 1 = 0 & <Σ 0 > = 0 Small: ρ-param

57 Finite Temperature Potential F F Multi-step EWSB transition: Step 1: quench sphalerons Step 2: move to EW/DM vac H 0 S!!

58 Real Triplet : DM Search Basic signature: Charged track disappearing after ~ 5 cm qq " W ±* " H ± H 2 qq " Z *,# * " H + H $ Trigger: Monojet (ISR) + large E T SM Background: QCD jz and jw w/ Z!νν & W!lν

59 Real Triplet : DM Search Basic signature: Charged track disappearing after ~ 5 cm qq " W ±* " H ± H 2 qq " Z *,# * " H + H $ Trigger: Monojet (ISR) + large E T SM Background: QCD jz and jw w/ Z!νν & W!lν Cuts: large E T hard jet One 5cm track

60 Real Triplet : DM Search Basic signature: Charged track disappearing after ~ 5 cm qq " W ±* " H ± H 2 qq " Z *,# * " H + H $ Cirelli et al: Trigger: Monojet (ISR) + large E T SM Background: QCD jz and jw w/ Z!νν & W!lν Cuts: large E T hard jet One 5cm track M Σ = 500 GeV: Ω Σ / Ω CDM ~ 0.1

61 SM Higgs? SM Branching Ratios? h j h j Σ + SM background well below D new γ CPV expectations D New expts: γ 10 2 to 10 3 more sensitive CPV needed for BAU? Four scalars: h 1 (Higgs-like) Σ 0 (dark matter) Σ +, Σ (new states) Fileviez-Perez, Patel, R-M, Wang h j D D

62 III. Is it a Scalar? Extension DOF EWPT DM Real singlet Real singlet Complex Singlet Real Triplet ?

63 III. Is it a Scalar? Extension DOF EWPT DM Real singlet Real singlet Complex Singlet Real Triplet ? Mixed Higgs-like states and/or modified BRs: signal reduction ξ, invisible search

64 III. Is it a Scalar? Extension DOF EWPT DM Real singlet Real singlet Complex Singlet Real Triplet ? Could be fermionic triplet [e.g., Buckley, Randall, Shuve, JHEP 1105 (2011) 97]. How to distinguish?

65 Di-Jet Correlations Buckley, R-M JHEP 1109 (2011) 094 V J 1 p 1 V p 2 J 2 R-hadrons from gg fusion Fermions Scalars

66 M 1 Di-Jet Correlations Buckley, R-M JHEP 1109 (2011) 094 M pair V V J 1 p 1 p 2 J 2 M 2 Scalars: A 3 / M pair 2 > 0 Fermions: A 3 < 0 Abelian Non-ableian for large Δ η

67 IV. Theoretical Issues Gauge-dependence in V EFF (ϕ, T ) V EFF (ϕ, T )! V EFF (ϕ, T ; ξ ) Ongoing research: approaches for carrying out tractable, GI computations H. Patel & MRM, JHEP 1107 (2011) 029 C. Wainwright, S. Profumo, MRM Phys Rev. D84 (2011) H. Gonderinger, H. Lim, & MRM, arxiv:

68 Origin of Gauge Dependence Effective Action Source term: Not GI Effective Potential

69 Nielsen Identities Identity: Extremal configurations: Effective potential:

70 Baryon Number Preservation Washout factor ln S ~ A(T C ) e ζ ζ = F(ϕ) Two qtys of interest: T C from V eff E sph from Γ eff

71 Baryon Number Preservation: Pert Theory ζ = F(ϕ) Conventional treatments ~ Gauge Dep GI T C from hbar exp, V eff (φ + φ), or Hamiltonian formulation Use GI scale in E sph computation Baryon number preservation criterion (BNPC) H. Patel & MRM, JHEP 1107 (2011) 029

72 Nielsen Identities: Application to T C Critical Temperature V eff (ϕ min, T C ) = V eff (0, T C ) Fukuda & Kugo 74: T=0 V EFF Laine 95 : 3D high-t Eff Theory Patel & R-M 11: Full high T Theory Apply consistently order-by-order in Implement minimization order-by-order (defines φ n )

73 Obtaining a GI T C Patel & R-M 11 Track evolution of minima with T using expansion n=1 n=2 n=3 Track evolution of different minima with T using Illustrative results in SM: Full φ

74 Gravity Waves from EWPT: Pert Theory Abelian Higgs Model C. Wainwright, S. Profumo, R-M Phys Rev. D84 (2011) arxiv: [hep-ph]

75 Vacuum Stability & Gauge Dependence Complex Singlet Model F F Tree-level stability H 0 S!! Possible runaway direction for δ 2 < 0 (EWPT) Full V EFF (1-loop): ξ-dependence GI Stability Condition Use β-fns M. Gonderinger, H. Lim, M. R-M arxiv: [hep-ph]

76 Conclusions Cosmology loves scalar fields (inflation): although no fundamental scalar yet observed, perhaps scalar fields can address a number of questions about the early universe Simple extensions of the SM scalar sector and lead to observable (σ SI, LHC) particle dark matter and/or EWPT with interesting implications: baryogenesis, GW, new Higgs states/modified Higgs properties. Perhaps observation of these scalars will point to a richer structure for scalar fields in the early universe involving both visible and dark physics