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Constraining Models of Neutrino Mass and Neutrino Interactions with the Planck Satellite

Friedland, Alexander and Zurek, Kathryn M. and Bashinsky, Sergei (2007) Constraining Models of Neutrino Mass and Neutrino Interactions with the Planck Satellite. . (Unpublished)

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In several classes of particle physics models -- ranging from the classical Majoron models, to the more recent scenarios of late neutrino masses or Mass-Varying Neutrinos -- one or more of the neutrinos are postulated to couple to a new light scalar field. As a result of this coupling, neutrinos in the early universe instead of streaming freely could form a self-coupled fluid, with potentially observable signatures in the Cosmic Microwave Background and the large scale structure of the universe. We re-examine the constraints on this scenario from the presently available cosmological data and investigate the sensitivity expected from the Planck satellite. In the first case, we find that the sensitivity strongly depends on which piece of data is used. The SDSS Main sample data, combined with WMAP and other data, disfavors the scenario of three coupled neutrinos at about the 3.5σ confidence level, but also favors a high number of freely streaming neutrinos, with the best fit at 5.2. If the matter power spectrum is instead taken from the SDSS Large Red Galaxy sample, best fit point has 2.5 freely streaming neutrinos, but the scenario with three coupled neutrinos becomes allowed at 2σ. In contrast, Planck alone will exclude even a single self-coupled neutrino at the 4.2σ confidence level, and will determine the total radiation at CMB epoch to ΔN^(eff)_ν = ^(+0.5)_(−0.3) (1σ errors). We investigate the robustness of this result with respect to the details of Planck's detector. This sensitivity to neutrino free-streaming implies that Planck will be capable of probing a large region of the Mass-Varying Neutrino parameter space. Planck may also be sensitive to a scale of neutrino mass generation as high as 1 TeV.

Item Type:Report or Paper (Discussion Paper)
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Additional Information:It is our pleasure to thank M. Perelstein for very helpful discussions and comments on the draft. We are also grateful to L. Hall, A. Lewis, A. Nelson and A. Smirnov for valuable suggestions and discussions. This work is supported in part by the U.S. Department of Energy under grant no. DE-FG02-95ER40896.
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Department of Energy (DOE)DE-FG02-95ER40896
Record Number:CaltechAUTHORS:20190611-154045590
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:96301
Deposited By: Tony Diaz
Deposited On:11 Jun 2019 23:07
Last Modified:03 Oct 2019 21:21

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