The Cosmological Moduli Problem (revisited)

Transcription

1 The Cosmological Moduli Problem (revisited) Scott Watson Syracuse University Reevaluating the Cosmological Origin of Dark Matter. e-print: arxiv: Acknowledgements: Bobby Acharya, Konstantin Bobkov, Dan Feldman, Phill Grajek, Gordy Kane, Piyush Kumar, Aaron Pierce, Dan Phalen, Jing Shao

2 Conclusions Inflation Non-thermal cosmology provides a viable alternative to the well motivated thermal scenario. TeV GeV MeV BBN Unlike the thermal case, a non-thermal history would imply a direct connection to fundamental theory and an observational window on the properties of the early universe. Working directly with fundamental theories nonthermal models can lead to predictions which are falsifiable in current and near term experiments. ev CMB Scott Watson

3 Non-thermal Cosmologies The idea of a non-thermal history is not new. Many phenomenological based toy models exist in the literature. Anomaly Mediated SUSY breaking Affleck-Dine condensates / Baryogenesis Wimpzillas Q-balls Many more... Can these ideas be realized within fundamental theory? Scott Watson

4 Non-thermal Cosmologies Establishing the likelihood of a non-thermal cosmology is important for a number of reasons: - It may alter the origin and expected properties of dark matter - It may result in new benchmarks for discovery at LHC - It may provide a window of opportunity for probing the early universe and fundamental theory (much like inflation) Scott Watson

5 Cosmic History TeV GeV MeV ev

6 Cosmic History TeV GeV Nucleosynthesis MeV ev

7 Cosmic History TeV GeV MeV Nucleosynthesis ev CMB First Stars Structure formation Dark Energy

8 Quantum Gravity Inflation GUTs Baryogenesis (p)reheating Cosmic History TeV GeV MeV Nucleosynthesis ev CMB First Stars Structure formation Dark Energy

9 Precision Cosmology Cosmic Energy Budget Today Dark Energy 72% Dark Matter 23% Baryons 5% Early universe remarkably homogeneous Very small density contrast (1:100,000) at time of decoupling of CMB All suggest physics beyond the standard model.

10 Quantum Gravity Inflation GUTs Baryogenesis (p)reheating Cosmic History? TeV GeV MeV Nucleosynthesis ev CMB First Stars Structure formation Dark Energy

11 Thermal Microscopic History Inflation Dark Matter Abundance from Thermal Production TeV GeV Dark Matter WIMPs? MeV BBN ev CMB

12 Thermal Microscopic History Inflation Dark Matter Abundance from Thermal Production TeV GeV Cosmological Measurement Weak Scale Physics Dark Matter WIMPs? MeV BBN ev CMB

13 Are things so simple?

14 Thermal Microscopic History Inflation Dark Matter Abundance from Thermal Production TeV GeV Cosmological Measurement Weak Scale Physics Dark Matter WIMPs? MeV ev BBN CMB *Assumed thermal equilibrium was reached *Assumed radiation dominated universe at freeze-out *Assumed no entropy production after freeze-out *Assumed no other sources of cdm (e.g. late decays)

15 Quantum Gravity Inflation GUTs Baryogenesis (p)reheating Cosmic History TeV GeV MeV Nucleosynthesis ev CMB First Stars Structure formation Dark Energy

16 Microscopic History Inflation Dynamical Symmetry Breaking (e.g. SUSY) Higgs / Strongly coupled dynamics? EWSB Phase Transition TeV GeV Dark Matter WIMPs MeV BBN QCD Phase Transition ev CMB

17 Light Scalars in the Early Universe Light scalars are a generic prediction of physics beyond the standard model Some have a geometric interpretation (e.g. extra dimensions), others are scalar partners of standard model fermions (SUSY) Low energy parameters become dynamical fields in early universe h h(t, x) m, g m(h),g(h) Many of these fields pass through cosmological phases where they have little or no potential: Approximate Moduli

18 Approximate Moduli Moduli Potential V ϕ (T,H,ϕ)=0+V soft + 1 M 2n ϕ4+2n +V SUGRA +V np +V thermal

19 Approximate Moduli Moduli Potential V ϕ (T,H,ϕ)=0+V soft + 1 M 2n ϕ4+2n +V SUGRA +V np +V thermal

20 Approximate Moduli Moduli Potential V ϕ (T,H,ϕ)=0+V soft + 1 M 2n ϕ4+2n +V SUGRA +V np +V thermal

21 Approximate Moduli Moduli Potential V ϕ (T,H,ϕ)=0+V soft + 1 M 2n ϕ4+2n +V SUGRA +V np +V thermal

22 Approximate Moduli Moduli Potential V ϕ (T,H,ϕ)=0+V soft + 1 M 2n ϕ4+2n +V SUGRA +V np +V thermal

23 Approximate Moduli Moduli Potential V ϕ (T,H,ϕ)=0+V soft + 1 M 2n ϕ4+2n +V SUGRA +V np +V thermal

24 Approximate Moduli Moduli Potential V ϕ (T,H,ϕ)=0+V soft + 1 M 2n ϕ4+2n +V SUGRA +V np +V thermal Example: Φ E Scalar Condensate

25 Scalar Condensates V (ϕ) Scalar Condensate forms Φ E ϕ Coherent Oscillations 2γ V (Φ) Φ γ, p = 2 + γ 1 ρ. γ = 0 p = ρ, Λ γ = 1 p = 1 3ρ, tadpole γ = 2 p = 0, matter γ = 4 p = 1 3ρ, radiation γ = ± p = ρ, stiff fluid

26 Cosmological Moduli Problem Coughlan, Fischler, Kolb, Raby, and Ross -- Phys. Lett. B131, 1983 Decay Gravitationally

27 Cosmological Moduli Problem Coughlan, Fischler, Kolb, Raby, and Ross -- Phys. Lett. B131, 1983 Decay Gravitationally Two possibilities: Stable m ϕ <TeV ρ mod <ρ c m ϕ < ev

28 Cosmological Moduli Problem Coughlan, Fischler, Kolb, Raby, and Ross -- Phys. Lett. B131, 1983 Decay Gravitationally Two possibilities: Stable m ϕ <TeV Decay m ϕ >TeV ρ mod <ρ c m ϕ < ev T r > 1 MeV (BBN) m ϕ > 10 TeV Concern: Decay to secondaries ( model dependent ) --> e.g. gravitino problem

29 Thermal relics and the Cosmological Moduli Problem Ω cdm m x T H T 2 σv T =T f Alter cosmic expansion (Salati - astro-ph/ , Chung, Everett, and Matchev - arxiv: ) Alter cross-section after freeze-out Phase transition (changing coupling) after freeze-out (Cohen, Morrissey, and Pierce - arxiv: ) Non-thermal Production (e.g. Decay of Light Scalar)

30 Example: Non-thermal Production of Dark Matter Inflation Initial Radiation Phase TeV GeV MeV BBN Moduli Domination begins Standard Thermal WIMP freeze-out Moduli Decay and Reheat - Dark matter from direct decay - Entropy produced (dilute relic densities) - Radiation dominated universe - Baryons?

31 Example: Non-thermal Dark Matter from Light Scalars Moroi and Randall -- hep-ph/ Dark Matter from Scalar Decay: V (ϕ) Moduli generically displaced in early universe Energy stored in scalar condensate Φ E Typically decays through gravitational coupling T r mφ 10 TeV 3/2 MeV ϕ Large entropy production dilutes existing dark matter of thermal origin 3 Ω cdm Ω cdm Tr T f Thermal abundance diluted

32 Example: Dark Matter from Scalar Decay Dark Matter will be replenished Given then dark matter populated non-thermally T r <T f Review: G. Kane, S.W. arxiv: Ω cdm m x T H T 2 σv T =T f T = T r 10 Ω NT 26 cdm =0.23 cm 3 /s Tf σv T r Freeze-out temp Reheat temp Allowed values still imply weak-scale physics WIMP Miracle survives Scott Watson

33 Are other cosmic histories possible? Yes.

34 Is a non-thermal history an exotic or a robust possibility?

35 Guidance from Fundamental Theory What is needed from a top-down approach: 4D Effective theory Spontaneously broken SUSY Explanation for how M EWSB M p Small and Positive Vacuum Energy In String theory, all these problems are related and are essentially a problem of stabilizing scalars. Scott Watson

36 What were the key ingredients? 1 Light Scalar m φ 10 TeV 2 3 Gravitationally coupled Γ φ m3 φ M 2 p Stable dark matter particle m x 100 GeV Scott Watson

37 What were the key ingredients? 1 Light Scalar m φ 10 TeV 2 Gravitationally coupled Light enough for decay after freeze-out, Heavy enough to evade BBN bounds Γ φ m3 φ M 2 p 3 Stable dark matter particle m x 100 GeV Scott Watson

38 The Cosmological Moduli Problem V = e Coughlan, Fischler, Kolb, Raby, and Ross -- Phys. Lett. B131, 1983 Banks, Kaplan, and Nelson -- Phys. Rev. D49, 1994 Model Independent properties and cosmological implications of the dilaton and moduli sectors of 4-d strings Carlos, Casas, and Quevedo -- Phys. Lett. B318, 1993 K m 2 p DW 2 3m 2 3/2 m2 p Shift symmetry Φ = φ + ia W = W (Φ)

39 The Cosmological Moduli Problem V = e Coughlan, Fischler, Kolb, Raby, and Ross -- Phys. Lett. B131, 1983 Banks, Kaplan, and Nelson -- Phys. Rev. D49, 1994 Model Independent properties and cosmological implications of the dilaton and moduli sectors of 4-d strings Carlos, Casas, and Quevedo -- Phys. Lett. B318, 1993 K m 2 p DW 2 3m 2 3/2 m2 p Shift symmetry Φ = φ + ia W = W (Φ) Zero vacuum energy, stabilize scalar, break SUSY (spontaneously) V (Φ) =m 2 3/2m 2 p f Φ m p m φ m 3/2 TeV Mismatch with UV minimum

40 Stabilizing the String Vacuum - Kofman, et. al. hep-th/ S.W. hep-th/ Cremonini & S.W. hep-th/ Greene, Judes, Levin, Weltman, & S.W. hep-th/ If scalars stabilized near points of enhanced symmetry this can prevent the formation of condensates (Dine) φ χ Study dynamics: - Scalars typically sample all of field space in finite time - These points are dynamical attractors (new d.o.f.)

41 Stabilizing Scalars in String Theory Include addition degrees of freedom: Gauge Fields / Branes Most scalars will receive string scale masses and stringy physics will decouple from the low energy theory m z M s GeV However, at least one light scalar typically remains W (φ) =W 0 + Ae aφ Nonperturbative stabilization at ds vacuum (w/ hierarchy respected) m φ m 3/2 TeV Scott Watson

42 Recipe for string vacuum (IIB) Step One: Flux provides stabilizing potential for many of the scalars in the theory (e.g. dilaton and structure moduli) String scale masses m z M s GeV At low scales most string scale physics decouples W = W 0

43 Recipe for string vacuum (IIB) Step One: W = W 0 Want: m 3/2 TeV m 3/2 = W 0 M 2 p V 6 W 0 1 V 6 1 (KKLT) or Large Volume V

44 Recipe for string vacuum (IIB) Step Two: Some scalars naturally remain light (Axionic shift symmetry / No scale structure) Stabilize by non-perturbative dynamics W = W 0 + Ae ax SUSY restored, Anti-deSitter Minimum V 0

45 Recipe for string vacuum (IIB) Final Step: Uplift (anti-brane / charged matter / string corrections) minimum to ds, SUSY broken Result: If W0 appropriately tuned (exponential and discrete) to preserve hierarchy: m φ log mp m 3/2 m 3/2

46 Other models with possible non-thermal contribution: Large Volume Compactifications e.g. Conlon and Quevedo -- arxiv: F-theory Heckman, Tavanfar, and Vafa-- arxiv: M-theory on G2 manifolds Acharya, et. al. -- arxiv: W = W 0 + c 1 f(φ)e ax + c 2 e bx

47 Other models with possible non-thermal contribution: Large Volume Compactifications F-theory M-theory on G2 manifolds Remarks e.g. Conlon and Quevedo -- arxiv: Heckman, Tavanfar, and Vafa-- arxiv: Acharya, et. al. -- arxiv: W = W 0 + c 1 f(φ)e ax + c 2 e bx Many open questions: Embedding visible sector, uplifting, path to 4d, SUSY breaking Gaugino (dark matter ) has three robust patterns The Gaugino Code, Choi and Nilles -- arxiv:hep-ph/ Light scalar may be robust prediction A Non-thermal WIMP Miracle, Acharya, et. al

48 A Non-thermal WIMP Miracle B. Acharya, G. Kane, P. Kumar, S.W. -- Phys. Rev. D80 arxiv: If scalars stabilized without reintroducing electroweak hierarchy and accounting for small and positive vacuum energy this typically implies: m φ m 3/2 TeV - Scalar decays into Dark Matter and radiation - Initial abundances diluted Ω cdm m x T H T 2 σv A new WIMP miracle Ω cdm Ω cdm Tr T f - Dark Matter produced in accordance with cosmological constraint with higher cross-section T =T r φ X 3

49 Some Phenomenological Implications of a Non-thermal history

50 SUSY Model Constraints Enforcing WMAP (blue) Ellis, et. al Scott Watson

51 SUSY Model Constraints Without Enforcing WMAP (blue) tan β =10,µ>0 Gelmini, Gondolo, Soldatenko, Yaguna hep-ph/ Scott Watson

52 PAMELA -- Indirect Evidence for WIMPs? Expected Positron Flux Φ σv m 2 x ρ 2 (r) Microphysics Astrophysics Important Considerations Astrophysical uncertainties: Halo profile, propagation, backgrounds Unknown astrophysical sources, e.g. Pulsars Proton contamination (10,000/1) Taken alone probably not a compelling case for dark matter

53 Larger cross-section can address PAMELA excess Figure by Ran Lu (grad student MCTP) Scott Watson

54 Pamela anti-protons Figure by Ran Lu (grad student MCTP)

55 Fermi predictions Figure by Ran Lu (grad student MCTP)

56 Photon-baryon heating during ionization from dark matter annihilation Slatyer, Padmanabhan and Finkbeiner

57 Conclusions Inflation Non-thermal cosmology provides a viable alternative to the well motivated thermal scenario. TeV GeV MeV BBN Unlike the thermal case, a non-thermal history would imply a direct connection to fundamental theory and an observational window on the properties of the early universe. Working directly with fundamental theories nonthermal models can lead to predictions which are falsifiable in current and near term experiments. ev CMB Scott Watson

58 April 1, 2011 Obama Solves Global Financial Crisis and Brings World Peace by Paul Krugman President Obama addressed the nation today acknowledging that although his administration has successfully resolved the global financial crisis, restored the confidence of the American housing market, and brought world peace, that there is still much left to be accomplished. The president has promised to turn to more mundane issues such as establishing a legitimate college football playoff, Experimental Result Leads to Excitement and Controversy by Dennis Overbye Ω cdm =0.002 To the physicist, the above expression succinctly summarizes the recent surprising results coming from the Large Hadron Collider (LHC) located in Geneva, Switzerland. The equation symbolically represents the amount of dark matter in the universe, which from the initial findings of the experiment seem to fall short of expectations coming from cosmological observation