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the cosmic photon background (CMB) evidently contains a lot of information about gravity and the structure of the universe
and it is expected that when instruments get good enough we will
see a cosmic neutrino background (CNB) consisting of even older particles
what do you know about this, what links have you found
I have only enough to whet my appetite and would like to find out more
(about what is expected or predicted, since we have no data yet)
Lineweaver, page 24, gives an estimate of the CNB temperature of 1.95 kelvin
A guy at last summer's "What Comes After the Standard Model" conference gave an estimate of 100 big bang neutrinos per cubic centimeter throughout space.
The proceedings of that conference were just posted on arxiv.
Gianpiero Mangano "Cosmological Neutrinos"
http://arxiv.org./hep-ph/0401055
Is anybody here up for guessing what, if anything, might be learned from observing CNB about quantum theories of spacetime.
this guy said that cosmology already gives a stronger bound on neutrino mass than is gotten from tritium-decay earthbound experiments. this is weird but here is the quote:
"We are pretty confident that our Universe is presently filled with quite a large number of neutrinos, of the order of 100 cm−3 for each flavor, despite of the fact that there are no direct evidences for this claim and,more sadly, it will be also very hard to achieve this goal in the future.
However several stages of the evolution of the Universe have been influenced by neutrinos, and their silent contribution has
been first communicated to other species via weak interactions, and eventually through their coupling with gravity. In fact, Big Bang Nucleosynthesis (BBN), the CosmicMicrowave Background (CMB) and the spectrum of Large Scale Structure (LSS) keep traces of their presence, so that by observing the power spectrum P(k),
the photon temperature-temperature angular correlation, and primordial abundances of light nuclei, we can obtain important pieces of information on several features of the neutrino background, as well as on some fundamental parameters, such as their mass scale.
It is astonishing, at least for all those of the elementary particle community who moved to ”astroparticle” physics, to see that in fact the present bound on the neutrino mass , order 1 eV, obtained by studying their effect on suppressing structure formation at small scales, is already stronger than the limit obtained in terrestrial measurement from 3H decay.
In this short lecture I briefly review some of the cosmological observables which indeed lead to relevant information on both dynamical (number density, chemical potential) and kinematical (masses) neutrino properties, as well as on extra weakly coupled light species.
2 Cosmological neutrinos: standard features
For large temperatures neutrinos are kept in thermodynamical equilibrium with other species, namely e− − e+ and nucleons, which in turn share the very same temperature of photons because of electromagnetic interactions..."
and so on. Mangano's article "cosmological neutrinos" is
in the rather long conference PDF file
http://arxiv.org./PS_cache/hep-ph/pdf/0401/0401055.pdf
and it is expected that when instruments get good enough we will
see a cosmic neutrino background (CNB) consisting of even older particles
what do you know about this, what links have you found
I have only enough to whet my appetite and would like to find out more
(about what is expected or predicted, since we have no data yet)
Lineweaver, page 24, gives an estimate of the CNB temperature of 1.95 kelvin
A guy at last summer's "What Comes After the Standard Model" conference gave an estimate of 100 big bang neutrinos per cubic centimeter throughout space.
The proceedings of that conference were just posted on arxiv.
Gianpiero Mangano "Cosmological Neutrinos"
http://arxiv.org./hep-ph/0401055
Is anybody here up for guessing what, if anything, might be learned from observing CNB about quantum theories of spacetime.
this guy said that cosmology already gives a stronger bound on neutrino mass than is gotten from tritium-decay earthbound experiments. this is weird but here is the quote:
"We are pretty confident that our Universe is presently filled with quite a large number of neutrinos, of the order of 100 cm−3 for each flavor, despite of the fact that there are no direct evidences for this claim and,more sadly, it will be also very hard to achieve this goal in the future.
However several stages of the evolution of the Universe have been influenced by neutrinos, and their silent contribution has
been first communicated to other species via weak interactions, and eventually through their coupling with gravity. In fact, Big Bang Nucleosynthesis (BBN), the CosmicMicrowave Background (CMB) and the spectrum of Large Scale Structure (LSS) keep traces of their presence, so that by observing the power spectrum P(k),
the photon temperature-temperature angular correlation, and primordial abundances of light nuclei, we can obtain important pieces of information on several features of the neutrino background, as well as on some fundamental parameters, such as their mass scale.
It is astonishing, at least for all those of the elementary particle community who moved to ”astroparticle” physics, to see that in fact the present bound on the neutrino mass , order 1 eV, obtained by studying their effect on suppressing structure formation at small scales, is already stronger than the limit obtained in terrestrial measurement from 3H decay.
In this short lecture I briefly review some of the cosmological observables which indeed lead to relevant information on both dynamical (number density, chemical potential) and kinematical (masses) neutrino properties, as well as on extra weakly coupled light species.
2 Cosmological neutrinos: standard features
For large temperatures neutrinos are kept in thermodynamical equilibrium with other species, namely e− − e+ and nucleons, which in turn share the very same temperature of photons because of electromagnetic interactions..."
and so on. Mangano's article "cosmological neutrinos" is
in the rather long conference PDF file
http://arxiv.org./PS_cache/hep-ph/pdf/0401/0401055.pdf
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