Dark Matter and Dark Energy from the solution of the strong CP problem Roberto Mainini, L. Colombo &...

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Transcript of Dark Matter and Dark Energy from the solution of the strong CP problem Roberto Mainini, L. Colombo &...

  • Dark Matter and Dark Energy from the solution of the strong CP problemRoberto Mainini, L. Colombo & S.A. BonomettoUniversita di Milano Bicocca

    Mainini & Bonometto Phys.Rev.Lett. 93 (2004) 121301Mainini, Colombo & Bonometto (2004) Apj submitted

  • Most cosmological data (CMB, SNIa, LSS) fitted byconcordance model (CDM)H 70 km/s/Mpc , n 1

    DM 0.3 , DE 0.7 , bar 0.04

    DE from cosmological constant but.. || < 10 -56 cm -2 why so small? (fine-tuning problem)

    . why DM DE ? (coincidence problem)

  • Dynamical DE models to ease CDM problems

    Tracking quintessence DE from a scalar field self-interacting through an effective potential V() but. . at least 1 more parameter required more complex models to try to unify DM and DE. Interacting DM-DE models coupling parameter also required

  • Dual-Axion Model Axion: DM candidate from Peccei-Quinn (PQ) solution to the strong CP problem modifying PQ model :- strong CP problem solved (even better so)

    DM and DE from single complex scalar field (exploit better the same fields as in PQ approach)

    no fine-tuning

    - number of parameter as SCDM (even 1 less than LCDM) DM an DE in fair proportion from one parameter

    - DM and DE coupled (this can be tested) but .. ..no extra parameter (coupling strength set by theory)

  • Strong CP problem Non-perturbative effects related to the vacuum structure of QCD leads a CP-violating term in LQCD :

    Neutron electric dipole moment

    Experimental limits on electric dipole moment

    Why is so small?

  • Peccei-Quinn solution and the axion Peccei & Quinn 1977PQ idea: CP-violating term is suppressed making a dynamical variable driven to zero by the action of its potential

    Additional global U(1)PQ symmetry in SM

    U(1)PQ is spontaneously broken at the scale FPQ - -parameter is now the NG boson due to sym.br. : the axion Weinberg 1978; Wilczek 1978

    with NG potential

  • - CP-violating terms generate a potential for the axion which acquires a mass m(T) (chiral symmetry break). From instantonic calculus:

    FPQ is a free parameter

    Cosmological and astrophysical constraints require:

  • Axion cosmology

    - Equation of motion (

  • Can a single scalar field account for both DM and DE? NG potential Tracker quintessence potential with a complex scalar field

    no longer constant but evolves over cosmological times

    PQ model

    Dual-Axion Model

    Angular oscillations are still axions while radial motion yields DE variation cause a dependence of the axion mass on scale factor a

  • LAGRANGIAN THEORYAXION

    DARK ENERGYFriction term modified: moredamping than PQ caseCOUPLED QUINTESSENCE MODEL with a time dependent coupling C()=1/

    Amendola 2000, 2003

  • Background evolution We use SUGRA potential

    Note: in a model with dynamical DE (coupled or uncoupled) once DM is assigned can be arbitrarily fixed. Here is univocally determined

  • Background evolution coupling term settles on different tracker solution

  • Background evolutionAfter equivalence the kinetic energy of DE is non-negligible during matter era

  • Density fluctuations: linear evolutionmodified friction termDM and baryons fluctuations described by 2 coupled Jeans equations:modified dynamical term

  • Density fluctuations: linear evolutionRed: dual axion C()=1/Blue: Coupled DE C=cost=Black: CDM Differences from CDM:- objects should form earlier - baryons fluct. keep below DM fluct. until very recently

  • Uncoupled SUGRASUGRA with C = costSUGRA with C= 1/SUGRA Dual-AxionFit to WMAP data- Main differences at low l- 2eff from 1.064 (uncoupled SUGRA) to 1.071 (C=1/)- SUGRA with C=1/ h=0.930.05Best fit parameters:

    Uncoupled SUGRAxxbh20.0250.001dmh20.120.02h0.630.060.210.07ns1.040.04A0.970.13Log 3.07.7

    SUGRA with C=costxxbh20.0240.001dmh20.110.02h0.740.110.180.07ns1.030.04A0.920.14Log -0.57.60.100.07

    SUGRA with C= 1/xxbh20.0250.001dmh20.110.02h0.930.050.260.04ns1.230.04A1.170.10Log 4.82.4

  • - One complex scalar field yields both DM & DE- Fair DM-DE proportions from one parameter : /GeV~1010- Strong CP problem solvedDM-DE coupling fixed (C=1/)Fluctuation growth is fair - Structure formation earlier than in CDMFair fit to WMAP data, constraining in the expected rangeSUGRA potential large H0 (~90 10 km/s/Mpc)Halo concentration and distribution to be tested, smaller concentrations expected

    Conclusions

  • Dynamical DE models to ease CDM problems

    Tracking quintessence DE from a scalar field self-interacting through an effective potential V() but. . at least 1 more parameter required Ex. : RP model we have to set the energetic scale more complex models to try to unify DM and DE. Interacting DM-DE models coupling parameter also required

  • Dark Matter (DM): non-baryonic component to account for dynamics in galaxies and galaxy clustersDark Energy (DE): smooth component with p
  • Axion mass variation cause a dependence of the axion mass on scale factor aRebounce at z=10 could be critical for structure formationMaccio et al 2004, Phys. Rev. D69, 123516

  • Some features of coupled quintessence model DM particles dont follow geodesics:violation of equivalence principle Newtonian interactions:

    - DM-DM particles - DM- baryons or baryons-barions= effective gravitational constantordinary gravitational constantModified DM dynamics could be critical for structure formation