2. In cosmology one can actually perform ultimate experiments, i.e.
those which contain ALL information available for measurement in the
sky. The first one of its kind is Planck (in primordial fluctuations in
Temperature) and in this decade we will also have such experiments
mapping the galaxy field. Question is: how much can we learn about
fundamental physics, if any, from such experiments?
My talk will cover a few examples:
1.Nature of the initial conditions and perturbations
2.Neutrinos
3.Beyond the Standard Model Physics
3. State of the art of data then (1992) …
(DMR)COBE
CMB
380000 yr
(a posteriori information)
~14 Gyr
Extremely successful model
6. Flat universe: Ωtot = 1.01 ± 0.01
Gaussianity: ƒNL < 13
Power Spectrum spectral index
nearly scale-invariant:
ns = 0.96 ± 0.01 (Planck only)
Adiabatic initial conditions
Superhorizon fluctuations
(TE anticorrelations)
WMAP TE
data in
bins of
∆l=10
Primordial Adiabatic i.c.
Causal
Seed model
(Durrer et
al. 2002)
Primordial
Isocurvature
i.c.
(Peiris et al. 2003)
Hu & Sujiyama 1995
Zaldarriaga & Harari 1995
Spergel & Zaldarriaga 1997
7. Gaussian but:
How small is small? In some models “small” can be “detectable”
Simplest inflationary models predict SMALL deviations from Gaussian initial
conditions
Many write:
Salopek Bond 1990; Gangui et al 1994;
Verde et al 2000 (VWHK);
Komatsu Spergel 2001
Gaussian
Defined on Gravitational potential
(actually Bardeen potential, important for sign)
This evolves in a LCDM universe… more later
And then say: “fNL” constant And call it “local” form
8. Relating the skewnness to the slow-roll parameters
But the primordial slope is
So a measurement of fNL and n gives you a measurement of the slow-roll parameters.
There is a minimum value of fNL > 0.04 (the tilt)…can we measure this?
fNL =
Verde, RJ, Kamionkowski, Matarrese MNRAS (2001)
11. Current obs. Constraint (Planck 2013)
Verde, Peiris, Jimenez (2003) JCAP
Inflation is probably small field class
Best limit ever?
12. Are neutrinos Dirac or Majorana?
(in other words, origin of neutrino mass: Higgs
mechanism or beyond the SM mechanism?)
13. Behaves like radiation at T~ eV (recombination/decoupling)
Eventually (possibly) becomes non-relativistic, behaves like
matter
Small interactions (not perfect fluid)
Has a high velocity dispersion (is “HOT”)
14. A relict of the big bang, similar to the
CMB except that the CvB
decouples from matter after
2s (~ MeV) not 380,000 years
At decoupling they are still relativistic (mν << Τν)
large velocity dispersions (1eV ~ 100 Km/s)
Recall:
T~1eV Matter-radiation equality,
T=0.26eV Recombination
60M nu/s/cm3
from the sun, ~100 from CvB
15. Total mass >~1 eV become non relativistic before recombination CMB
Total mass <~1 eV become non relativistic after recombination:
alters matter-radn equality but effect can be “cancelled”
by other parameters Degeneracy
After recombination
FINITE NEUTRINO MASSES
SUPPRESS THE MATTER POWER
SPECTRUM ON SCALES SMALLER
THAN THE FREE-STREAMING
LENGTH
m =Σ 0 eV
m =Σ 0.3 eV
m =Σ 1 eV
P(k)/P(k,mν=0)
linear theory
16. Oscillations indicate neutrinos have mass:
Three possible hierarchies
Physics beyond the standard model?
The standard model has 3 neutrino species, but…
Neutrino mass eigenstates are not the same as flavor
NORMAL INVERTED
DEGENERATE
∆matmo
∆msol
∆matmo
∆msol
Total v mass increases
24. Any thermal background of light particles, anything affecting expansion rate
Look at BBN
Neff=3.045Standard:
Neff around 3 to 4
Systematics!
Look at CMB:
effects matter-radn equality
and so sound horizon at decoupling
-> degeneracy with ωm and H
Anisotropic stress,
zeq on diffusion damping
From WMAP9: Hinshaw et al 2012
WMAP
ACT
SPT
25. WMAP only WMAP+H0+BAO
The adopted H0 value matters!
For aficionados:
Straight from the on-line LAMBDA cosmological parameters plotter
26. Verde, RJ, Feeney 2013 arXiv:1301.5341
Planck2013
WMAP9
tU from subgiant HD140283, with very
precise parallax, error budget dominated
by uncertainty in oxygen abundance.
29. Based on:
Arxiv:1004.2053 (JCAP 2010)Arxiv:1004.2053 (JCAP 2010)
Arxiv:0902.2006 (JCAP 2009)Arxiv:0902.2006 (JCAP 2009)
Update this month on arXivUpdate this month on arXiv
with A. Avgoustidis, C. Burrage, J. Redondo & L. Verdewith A. Avgoustidis, C. Burrage, J. Redondo & L. Verde
30.
31.
32. Luminosity distance:
Inferred from standard candles, notably Ia SNae
(from standard rulers)
• Ang. diameter distance related through Etherington
relation:
?
If photon number conservation is violated, there will be
a mismatch in the above due to a non-trivial “opacity”
:
This can happen if photons are converted to ALPs along line of
sight
33. Measure from SN observations
Can constrain jointly ALP coupling and cosmological
parameters by using SN and H(z) (or BAO) data.
Any ALP coupling to photons via or
will produce non-trivial opacity.
Predict from H(z) data
constrain
34. Run likelihood analysis for flat ΛCDM models in
Constrain opacity parameter(s) by marginalising over cosmologies:
•For ALPs:
•For MCPs:
Initial SN flux mix: Photon-axion conversion
probability
Rate of
35. SN only SN + H(z)
No photon-axion mixing
Flux thermalised at SN:
no propagation effect
Rapid photon-axion thermalization
Fits SNae w/o Λ
(Csaki et al 2002)
Ruled out by H(z)
36. Dramatic improvement on these constraints expected with
future BAO (notably EUCLID) and SN missions
Mini-Charged Particles
Simple Axions
Opacity
37. • Vast quantity of high quality cosmo data fast
approaching: CMB, BAOs, Gravitational waves, 21cm,...
• Fruitful interplay between HEP/cosmo theory and
cosmological observation
• New physics at sub-eV scales (notably ALPs & MCPs)
generic in fundamental theory
• A good chance to measure neutrino mass and hierarchy
• Dramatic improvement expected as new data arrives and
astrophysics better understood
Notas do Editor
Although many issues are still open…
TE correlation shows modulation between velocity mode and density mode, which has a peak on scales larger than the horizon scale at decoupling.
Don’t interpret points statistically! Each point has equal weight Not every point coincides with a physically realistic model Monte Carlo realizations of inflationary flow equations
Nu decouping 1Mev e+ e- annihilation at 0.2eV Tphotons> Tnu a temp N, neff (QED effects and non instantaneous decoupling)…. Cosmology is sensitive to Neff primarily because energy density in relativistic particles affects directly the universe’s expansion rate during the radiation domination era. H^2(t) propto rhogamma +rhonu any thermal background of light particles such as axions and axion-like particles, hidden sector photons, majorons, or even gravitons will contribute to the relativistic energy density. Likewise, any process that alters the thermal abundance of neutrinos (e.g., a low reheating temperature) or affects directly the expansion rate itself (e.g., a time-dependentNewton’sconstantG)canmimicanon-standardNeff value. BBN!