3 astrophysical measurements of neutrino mass

• Neutrino mass will tend to wash out intermediate scale structure during galaxy formation. Thus the presence of such structure in the present day distributions of galaxies disfavours neutrino mass.

• The Z-burst model for the origin of supra-GZK cosmic rays requires a non-zero neutrino mass.

• See hep-ph/0308168 for a method based on supernova neutrinos observed around a gravitational lens. It only requires you to see supernova neutrinos around a gravitational lens. That shouldn’t be too hard….

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Imperial College/RAL

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Dave Wark

2dF Galaxy Redshift Survey

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Dave Wark

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Dave Wark

P(k)=A kn T2(k)

Neutrino Free StreamingNeutrino Free Streaming

P(k)/P(k) = -8 P(k)/P(k) = -8 m (Hu et al. 1998)m (Hu et al. 1998)

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Imperial College/RAL

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Dave Wark

=0

=0.01=0.05

They derive m,tot < 1.8 eV

2dF

team

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ro-p

h/02

0415

2

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Imperial College/RAL

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Dave Wark

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Dave Wark

astro-ph/0302209

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Dave Wark

astro-ph/0304237

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astro-ph/0306386

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Dave Wark

Neutrino mass from Cosmology

Data Authors Mmi

2dFGRS Elgaroy et al. 02 < 1.8 eV

WMAP+2dF+… Spergel et al. 03 < 0.7 eV

WMAP+2dF Hannestad 03 < 1.0 eV

SDSS+WMAP Tegmark et al. 04 < 1.7 eV

WMAP+2dF+

SDSS

Crotty et al. 04 < 1.0 eV

Clusters +WMAP Allen et al. 04 0.56+0.30-0.26 eV

All upper limits 95% CL, but different assumed priors !All upper limits 95% CL, but different assumed priors ! Slide from Ofer Lahav

What does this mean for neutrino physics?

• Sensitivity is better than tritium, and currently comparable to 0 decay – but clearly at this time suffers from substantial model dependencies.

• Data improve with more MAP data, Planck, and the Sloan Digital Sky Survey, perhaps gaining another factor of 3-5 in potential sensitivity. (See astro-ph/0303344, which claims (m) = 0.15 eV from Planck alone, and eventually perhaps 0.04 eV from better CMBR measurements)

• What are the real model dependencies? Hubble parameter? Bias? What is a model-independent limit? Time will tell. Watch, or better yet, join in the fun.

• Real connection between particle physics and cosmology!

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Dave Wark