Neutrino (Mass) in Cosmology

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Neutrino (Mass) in Cosmology
Thomas J. Weiler Vanderbilt University Nashville
TN 37235, and CERN, Geneva, Switzerland
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Early-Universe Timeline
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Friedmann eqns, and energy partitions Omega
with a being the cosmic scale factor
So L behaves like a matter with 3pr lt 0 !
Can relate (F1) parameters to todays values to
write
Omegar/rcrit, rcrit6 protons/m3
Inflation and data ? OmegaK 0
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Neutrino Decoupling
Looking back, ns last scattered at time t such
that
i.e. GF2 T5 T2/MP ,
TnDC MeV, t 1 s, z 1010. Coincidentally
, TnDC TBBN Tee-
vs. zeq a0/aeq Omegarad/Omegam 4000,
zrecomb 1100. Coincidentally, Teq Trecomb eV
mn
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Neutrino stat mech
per flavor
HDM models tried (top-down) Omegan1, i.e. each
mn30eV
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Neutrino density from BB photon density
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nn, ng gtgt any other density
SN87a
sun
Neutrino Incognito
CnB
hadron wall?
no wall atall
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Neutrino time
Liberated at TMev, t 1 sec Depends on energy
(Lorentz boost)
Consider a 1020 eV neutrino. Lorentz factor
1021 for mn 0.1 eV. Age of Uni is 1018
sec, But age of n is 1018/1021 sec 1
millisecond ! And it doesnt even see the stream
of radiation rushing past it untouched !
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CR Spectrum above a TeV
from Tom Gaisser
50 Joules
VLHC (100 TeV)2
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BBN limits on Nn and asymmetry

• Competing effects
• Weak intn rate equilibrates nen ?? pe- , as
  n/p exp-dmN/TnDC
• So more ne ? less neutrons ? less He/H
• Expansion rate (monotonic with Nn) decouples weak
  intn
• So more Nn ? faster movie, earlier hotter TnDC
  and more neutrons ? more He/H

Kneller Steigman
H? S H, S
So one extra species is DS0.08
Best fit is DN0.25, L2.5
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Compensation and LSND
Order 5 neutrino asymmetry -- to be contrasted
with 10-9 baryon asymmetry
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Four roads to absolute neutrino mass(SN
discounted)

• 1. Tritium decay
• 2. 0vbb decay
• 3. WMAP ? LSS
• 4. Z-bursts on the relic CnB

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Tritium decay limits on neutrino mass
Q Why tritium? A It has a small Q-value,
mT-(mDmpme)
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The oscillation box from a Feynman graph
Where does the mixing matrix come in?
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PMNS neutrino-mixing matrix
Weak-interaction and mass vectors point
differently nkgtUki nigt, or Uki ltni nkgt
ltnk nigt
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What we think we know about neutrino mass
Log m2
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Or maybe
It looks like this
Log m2
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Naturalness may be over-rated
Do these look natural?
A rodent with a bill?
Or a bug with a light-emitting tush?
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0nbb decay limits on neutrino mass
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Neutrino parameters fundamental to physics, and
a tool for astrophysics/cosmology
As an astro tool, useful NOW (e.g. Le Lm Lt )
As a physics window, the view is unclear.
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neutrino masses and cosmology
r of rcr
first task bound n mass
second task decide whether n contribute as Hot
Dark Matter
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Cosmic structure formation
WMAP ? 2dF/SDSS

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COBE data

• The raw temperature map (top) has a large
  diagonal asymmetry due to our motion with respect
  to the cosmic microwave background
• a Doppler shift.
• The temperature fluctuations after subtraction
  of the velocity contribution,
• showing primordial fluctuations and a large radio
  signal from nearby sources in our own galaxy (the
  horizontal strip).
• The primordial fluctuations after subtraction of
  the galaxy signal.

V

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WMAP data
The Universe at trecombination , tequality
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2dF Galaxy Redshift Survey
Peak from horizon scale at teq
HDM contributes to suppression of Small scales
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New length scale from neutrino mass
LSS formation is a battle between attractive
gravity and repulsive pressure the battle-line
is the Jeans length (4pGr/vs2)1/2 (4pG/p)1/2
. The
knr (Omegan/Omegam)1/2 Omegam
WMAP
Today k gt
LSS
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Tegmark cosmic cinema - CDM
http//www.hep.upenn.edu/max/cmb/movies.html
Increasing the total density of matter (baryons
cold dark matter) pushes the epoch of
matter-radiation equality back in time and moves
the peak scale (the horizion size at that time)
to the right.
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Tegmark cosmic cinema - HDM
Increasing the density of massive neutrinos
suppresses all scales smaller than a certain
cutoff, which in turn shifts to the left as you
increase the neutrino mass (and density)
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Tegmark cosmic cinema more HDM
If a CMB theorist gloats that he or she can
measure the neutrino density, make sure to point
out that galaxy surveys are much more sensitive.
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A little HDM history
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Neutrino fits
Elgaroy and Lahav
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SDSS (Seljak et al)
Increasing nu mass increases CMB spectrum, But
decreases matter power spectrum ??

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Role of priors (Elgaroy and Kahav)
Elgaroy and Lahav
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Resonant Neutrino Annihilation Mean-Free-Path
l(nn sn)-1 40 DH/h70
Fig Fargion, Mele, Salis
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Eschers Angels and Devils
 
The early Uni was denser, more absorbing.
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Neutrino mass-spectroscopy absorption and
emission
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Z-bursts
TJW, 1982 Revival 1997
50 Mpc
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n-mass spectroscopy
zmax2, 5, 20 (top to bottom), n-a2 (bottom-up
acceleration) Eberle, Ringwald, Song, TJW, 2004
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Dips sobering realism

• hidden MX4 1014 and 1016 GeV,
• to explain gtGZK w/ Z-bursts
• mass 0.2 (0.4) eV - dashed (solid)
• Error bars per energy decade, by 2013,
• for flux saturating present limits

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The GZK puzzle
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Z-burst spectrum
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Fitted Z-burst (Emission) Flux
Gelmini, Varieschi, TJW


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Nu-mass limit for Z-burst fitted to EECRs
Gelmini, Varieschi, TJW

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Size matters
EUSO 300 x AGASA 10 x Auger EUSO
(Instantaneous) 3000 x AGASA 100 x Auger
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clear moonless nights
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See-saw (Leptogenesis to follow)
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Leptogenesis

• Three Sakharov conditions for Violate baryon
  number (B-L conserved gt Baryogenesis
• DB (DL) nonzero
• Violate C and CP ? T (complex couplings)
• Out of Thermal Equilibrium
• (decouple at T gt M so no Boltzmann suppression,
• then decay at T lt M when over-abundant)

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Extra-dimensions and neutrino mass
Right-handed sterile neutrinos may be our
probe of extra-dimensions
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Summary
Neutrinos are a splendid example of the
interplay among particle physics, astrophysics,
and cosmology
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The Learned Plot
Oscillation phase is . ( L dm2 / 4 En )
Figure parameterized by dm2 / (eV)2
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Neutrino Decay -- Models, Signatures, and Reach
P(survive) e t/t e (L/E)(m/t0)
Beacom, Bell, Hooper, Pakvasa, TJW
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The cosmic n flavor-mixing thm
If theta32 is maximal (it is), And if Re(Ue3) is
minimal (it is), Then nm and nt
equilibrate Further, if initial ne flux is
1/3 (as from pion-muon decay chain), Then all
three flavors equilibrate.
nenmnt 1 1 1 at Earth
(and deviations ? new physics)
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AMANDA/IceCube nm event
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Flavor ratio ? Topology ratio Map
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Sensitivity of n1 flavor-projection to
MNS parameters
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pseudo-Dirac masses and cosmic neutrinos
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Z-burst schematic
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Neutrino Mass tomography in the Local
Super-galactic Cluster
(Fodor, Katz, Ringwald)
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Integrated Sachs-Wolfe effect