Inflation as a Cosmological Collider

Transcription

1 Inflation as a Cosmological Collider Yi Wang 王一, The Hong Kong University of Science and Technology

2 Cosmological Collider Status Yi Wang 王一, The Hong Kong University of Science and Technology

3 Cosmological Collider Status & Future Yi Wang 王一, The Hong Kong University of Science and Technology

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5 Image: Princeton University

6 Building colliders Image: Princeton University

7 Building colliders Lesson: - New physics appears log EE - Cost of colliders EE power Still very important but costly! Image: Princeton University

8 Building colliders Lesson: - New physics appears log EE - Cost of colliders EE power Still very important but costly! Image: Princeton University

9 High energies in nature

10 High energies in nature: - Black holes

11 High energies in nature: - Black holes - The early universe Image: WMAP

12 High energies in nature: - Black holes - The early universe Probably the highest energy in our universe Is it a collider? Image: WMAP

13 High energies in nature: - Black holes - The early universe Probably the highest energy in our universe Is it a collider? Image: WMAP

14 HEP process: Create heavy particles Let them interact Long-lived signals Detectors

15 Man-made HEP at Higher colliders Energies? What s needed e.g. as LHC a collider? leptons, photons, jets e.g. ATLAS, CMS HEP process: Create heavy particles Let them interact Long-lived signals Detectors

16 Man-made HEP at Higher colliders Energies? e.g. LHC leptons, photons, jets e.g. ATLAS, CMS HEP process: Create heavy particles Let them interact Long-lived signals Detectors Inflation of the very early universe aa tt exp(hhhh) TT GGGG HH is up to GeV The cosmological collider

17 Man-made HEP at Higher colliders Energies? e.g. LHC leptons, photons, jets e.g. ATLAS, CMS HEP process: Create heavy particles Let them interact Long-lived signals Detectors Inflation of the very early universe aa tt exp(hhhh) TT GGGG HH is up to GeV The cosmological collider Classical conserved quantities, such as: curvature pert ζζ PGW γγ iiii, isocurvature

18 The curvature perturbation ζζ xx δδδδ xx HH φφ δδδδ φφ = φφ 0 tt + δδδδ xx, tt Intuitive (probably too rough) TT GGHH HH δδδδ HH Formalism: QFT in curved spacetime SS = dd 3 xx dddd aa 3 tt φφ 2 2 +, δδφφ nn xx, tt = TTee ii dddd HH II δδφφ II tt nn tt TTee ii dddd HH II, δδφφ 2 HH 2, δδφφ 3 PGW & remaining isocurvature fluctuation (if any): similarly Inflation of the very early universe aa tt exp(hhhh) TT GGGG HH is up to GeV The cosmological collider Classical conserved quantities, such as: curvature pert ζζ PGW γγ iiii, isocurvature

19 Man-made HEP at Higher colliders Energies? e.g. LHC leptons, photons, jets e.g. ATLAS, CMS HEP process: Create heavy particles Let them interact Long-lived signals Detectors Inflation of the very early universe aa tt exp(hhhh) TT GGGG HH is up to GeV The cosmological collider Classical conserved quantities, such as: curvature pert ζζ PGW γγ iiii, isocurvature Cosmological observations, e.g. CMB, LSS, 21cm

20 Observations: Correlation functions of - Curvature perturbation ζζ - From CMB ΔTT/TT, LSS & 21cm δδδδ/ρρ - Status: 2pt well measured (COBE DMR) - 3pt, (non-gaussianity) not yet observed - PGW: From CMB B-mode, not yet observed - Isocurvature: From details of CMB/LSS, not yet observed Inflation of the very early universe aa tt exp(hhhh) TT GGGG HH is up to GeV The cosmological collider Classical conserved quantities, such as: curvature pert ζζ PGW γγ iiii, isocurvature Cosmological observations, e.g. CMB, LSS, 21cm

21 Man-made HEP at Higher colliders Energies? e.g. LHC leptons, photons, jets What can be studied? e.g. ATLAS, CMS HEP process: Create heavy particles Let them interact Long-lived signals Detectors Inflation of the very early universe aa tt exp(hhhh) TT GGGG HH is up to GeV The cosmological collider Classical conserved quantities, such as: curvature pert ζζ PGW γγ iiii, isocurvature Cosmological observations, e.g. CMB, LSS, 21cm What can be studied?

22 What can be studied? Information in correlation functions: Mass: resonance in energy dependence Spin: angular dependence Interactions: size & energy envelop

23 What can be studied? Information in correlation functions: Mass: resonance in energy dependence Chen & YW, , Arkani-Hamed & Maldacena, Spin: angular dependence Arkani-Hamed & Maldacena, Baumann, Goon, Lee, Pimentel, Interactions: size & energy envelop Model dependent, lots of studies

24 What can be studied? Mass: what s the resonance? Heavy particle: mass mm prob: exp( mm / TT GGHH ) kk prod : kk prod aa prod mm (resonant production) tt

25 kk decay : kk decay aa decay mm (resonant decay) What can be studied? Mass: what s the resonance? Heavy particle: mass mm prob: exp( mm / TT GGHH ) kk prod : kk prod aa prod mm (resonant production) kk prod kk prod tt

26 kk decay : kk decay aa decay mm (resonant decay) What can be studied? Mass: what s the resonance? Heavy particle: mass mm prob: exp( mm / TT GGHH ) phase changed by ee iiiiii kk prod : kk prod aa prod mm (resonant production) kk prod kk prod tt

27 kk decay : kk decay aa decay mm (resonant decay) What can be studied? Mass: what s the resonance? From resonance to interference interference: phase changed by ee iiiiii corr exp iiii(tt decay tt prod ) kk decay kk prod iiii/hh kk prod : kk prod aa prod mm

28 kk 3 kk 1 kk 2 What can be studied? Mass: what s the resonance? From resonance to interference interference: corr exp iiii(tt decay tt prod ) kk decay kk prod iiii/hh actually μμ = mm HH 2 9 4

29 What s at the energy scale HH?

30 What s at the energy scale HH? Accidentally near HH? - Grand unification - Neutrino seesaw Chen, Wang & Xianyu,

31 Uplifted to HH scale: - Standard Model h 2 HH 2 What s at the energy scale HH? λλh 4 λλ h 2 h 2 mm 2 eff h 2 also: possible h 2 RR HH 2 h 2 Chen & YW, Chen, YW & Xianyu, Kumar & Sundrum, Accidentally near HH? - Grand unification - Neutrino seesaw Chen, Wang & Xianyu,

32 What can be studied? Mass: what s the resonance? From resonance to interference What s at the energy scale HH? Uplifted to HH scale: - Standard Model h 2 HH 2 λλh 4 λλ h 2 h 2 mm 2 eff h 2 also: possible h 2 RR HH 2 h 2 Chen & YW, Chen, YW & Xianyu, Kumar & Sundrum, Accidentally near HH? - Grand unification - Neutrino seesaw Chen, Wang & Xianyu,

33 What can be studied? Mass: what s the resonance? From resonance to interference What s at the energy scale HH? Accidentally near HH? - Grand unification - Neutrino seesaw Chen, Wang & Xianyu, Uplifted to HH scale: - Standard Model h 2 HH 2 λλh 4 λλ h 2 h 2 mm 2 eff h 2 also: possible h 2 RR HH 2 h 2 Chen & YW, Chen, YW & Xianyu, Kumar & Sundrum, SUSY breaking Baumann & Green, Delacretaz, Gorbenko & Senatore

34 What can be studied? Mass: what s the resonance? From resonance to interference What s at the energy scale HH? How is the collider built? Expansion history Chen, Namjoo & YW, Testing QM Maldacena, Correction to 2pt Jiang & YW,

35 What can be studied? Mass: what s the resonance? From resonance to interference What s at the energy scale HH? How is the collider built? vs Has inflation indeed happened?

36 Precision Era: Haven t we known our universe very well? vs Chen, Namjoo & YW,

37 Precision Era: Haven t we known our universe very well? Image: Planck Team

38 We know fluctuations as Precision Era: Haven t we known our universe very well? functions of scales (k) very well. kk 1/ττ (conformal time) Thus we know fluctuation conformal time ττ But what about fluctuation physical time t?

39 We know fluctuations as Precision Era: Haven t we known our universe very well? functions of scales (k) very well. kk 1/ττ (conformal time) Thus we know fluctuation conformal time ττ But what about fluctuation physical time t?

40 phase changed by ee iiiiii physical mass physical time Thus ττ tt dddd/dddd = aa We know fluctuations as functions of scales (k) very well. kk 1/ττ (conformal time) Thus we know fluctuation conformal time ττ But what about fluctuation physical time t? kk prod kk prod X. Chen, Namjoo & YW,

41 inverse functions direct probe of expansion history phase changed by ee iiiiii physical mass physical time Thus ττ tt dddd/dddd = aa aa tt pp then φφ kk1 φφ kk2 φφ kk3 cos kk 1 kk 3 1 pp kk prod kk prod X. Chen, Namjoo & YW,

42 What can be studied? Mass: what s the resonance? From resonance to interference Status?? What s at the energy scale HH? How is the collider built? Has inflation indeed happened?

43 COBE (1990s) Δff NNNN ~ 2000 WMAP 1yr (2003) Δff NNNN ~ 100 7yr (2010) Δff NNNN ~ 20 PLANCK (2013) Δff NNNN ~ 5 21 cm Cosmology Large Scale Structure For example: SphereX Δff NNNN ~ 0.5? Δff NNNN ~ 10 3? See e.g Meerburg, Münchmeyer, Muñoz and Chen Challenges for observations

44 What can be studied? Mass: what s the resonance? From resonance to interference What s at the energy scale HH? How is the collider built? Has inflation indeed happened? Challenges for observations Thank you! Main References: X. Chen & YW, , , D. Baumann & D. Green, Noumi, Yamaguchi & D. Yokoyama Gong, Sasaki & Pi N. Arkani-Hamed & J. Maldacena, X. Chen, Namjoo & YW, , X. Chen, YW & Z. Z. Xianyu, , An, McAneny, Ridgway & Wise, S. Kumar & R. Sundrum, and so on Acknowledgment This talk is supported in part by Grants ECS and GRF from Research Grants Council (RGC) of Hong Kong