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Author |
Archidiacono, M.; Giusarma, E.; Hannestad, S.; Mena, O. |
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Title |
Cosmic Dark Radiation and Neutrinos |
Type |
Journal Article |
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Year |
2013 |
Publication |
Advances in High Energy Physics |
Abbreviated Journal |
Adv. High. Energy Phys. |
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Volume |
2013 |
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Pages  |
191047 - 14pp |
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Abstract |
New measurements of the cosmic microwave background (CMB) by the Planck mission have greatly increased our knowledge about the universe. Dark radiation, a weakly interacting component of radiation, is one of the important ingredients in our cosmological model which is testable by Planck and other observational probes. At the moment, the possible existence of dark radiation is an unsolved question. For instance, the discrepancy between the value of the Hubble constant, H-0, inferred from the Planck data and local measurements of H-0 can to some extent be alleviated by enlarging the minimal ACDM model to include additional relativistic degrees of freedom. From a fundamental physics point of view, dark radiation is no less interesting. Indeed, it could well be one of the most accessible windows to physics beyond the standard model, for example, sterile neutrinos. Here, we review the most recent cosmological results including a complete investigation of the dark radiation sector in order to provide an overview of models that are still compatible with new cosmological observations. Furthermore, we update the cosmological constraints on neutrino physics and dark radiation properties focusing on tensions between data sets and degeneracies among parameters that can degrade our information or mimic the existence of extra species. |
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Address |
[Archidiacono, Maria; Hannestad, Steen] Univ Aarhus, Dept Phys & Astron, DK-8000 Aarhus C, Denmark, Email: archi@phys.au.dk |
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Hindawi Publishing Corporation |
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English |
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ISSN |
1687-7357 |
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Notes |
WOS:000327959400001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1660 |
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Author |
Pandolfi, S.; Giusarma, E.; Kolb, E.W.; Lattanzi, M.; Melchiorri, A.; Mena, O.; Pena, M.; Cooray, A.; Serra, P. |
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Title |
Impact of general reionization scenarios on extraction of inflationary parameters |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
82 |
Issue |
12 |
Pages |
123527 - 10pp |
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Keywords |
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Abstract |
Determination of whether the Harrison-Zel'dovich spectrum for primordial scalar perturbations is consistent with observations is sensitive to assumptions about the reionization scenario. In light of this result, we revisit constraints on inflationary models using more general reionization scenarios. While the bounds on the tensor-to-scalar ratio are largely unmodified, when different reionization schemes are addressed, hybrid models are back into the inflationary game. In the general reionization picture, we reconstruct both the shape and amplitude of the inflaton potential. We discuss how relaxing the simple reionization restriction affects the reconstruction of the potential through the changes in the constraints on the spectral index, the tensor-to-scalar ratio and the running of the spectral index. We also find that the inclusion of other Cosmic Microwave Background data in addition to the Wilkinson Microwave Anisotropy probe data excludes the very flat potentials typical of models in which the inflationary evolution reaches a late-time attractor, as a consequence of the fact that the running of the spectral index is constrained to be different from zero at 99% confidence level. |
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Address |
[Pandolfi, Stefania; Lattanzi, Massimiliano; Melchiorri, Alessandro] Univ Roma La Sapienza, Dept Phys, I-00185 Rome, Italy |
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Publisher |
Amer Physical Soc |
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English |
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ISSN |
1550-7998 |
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Notes |
ISI:000286744800007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
530 |
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Author |
Pandolfi, S.; Cooray, A.; Giusarma, E.; Kolb, E.W.; Melchiorri, A.; Mena, O.; Serra, P. |
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Title |
Harrison-Zel'dovich primordial spectrum is consistent with observations |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
81 |
Issue |
12 |
Pages |
123509 - 6pp |
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Keywords |
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Abstract |
Inflation predicts primordial scalar perturbations with a nearly scale-invariant spectrum and a spectral index approximately unity [the Harrison-Zel'dovich (HZ) spectrum]. The first important step for inflationary cosmology is to check the consistency of the HZ primordial spectrum with current observations. Recent analyses have claimed that a HZ primordial spectrum is excluded at more than 99% c. l. Here we show that the HZ spectrum is only marginally disfavored if one considers a more general reionization scenario. Data from the Planck mission will settle the issue. |
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Address |
[Pandolfi, Stefania] Univ Roma La Sapienza, ICRA, I-00185 Rome, Italy |
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Amer Physical Soc |
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English |
Summary Language |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1550-7998 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000278555900003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
426 |
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Author |
Di Valentino, E.; Gariazzo, S.; Giusarma, E.; Mena, O. |
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Title |
Robustness of cosmological axion mass limits |
Type |
Journal Article |
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Year |
2015 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
91 |
Issue |
12 |
Pages |
123505 - 12pp |
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Keywords |
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Abstract |
We present the cosmological bounds on the thermal axion mass in an extended cosmological scenario in which the primordial power spectrum of scalar perturbations differs from the usual power-law shape predicted by the simplest inflationary models. The power spectrum is instead modeled by means of a “piecewise cubic Hermite interpolating polynomial” (PCHIP). When using cosmic microwave background measurements combined with other cosmological data sets, the thermal axion mass constraints are degraded only slightly. The addition of the measurements of sigma(8) and Omega(m) from the 2013 Planck cluster catalog on galaxy number counts relaxes the bounds on the thermal axion mass, mildly favoring a similar to 1 eV axion mass, regardless of the model adopted for the primordial power spectrum. However, in general, such a preference disappears if the sum of the three active neutrino masses is also considered as a free parameter in our numerical analyses, due to the strong correlation between the masses of these two hot thermal relics. |
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Address |
[Di Valentino, Eleonora] CNRS, UMR 7095, Inst Astrophys Paris, F-75014 Paris, France |
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Publisher |
Amer Physical Soc |
Place of Publication |
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English |
Summary Language |
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Original Title |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1550-7998 |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000355623400003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2253 |
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Author |
Vagnozzi, S.; Giusarma, E.; Mena, O.; Freese, K.; Gerbino, M.; Ho, S.; Lattanzi, M. |
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Title |
Unveiling nu secrets with cosmological data: Neutrino masses and mass hierarchy |
Type |
Journal Article |
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Year |
2017 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
96 |
Issue |
12 |
Pages |
123503 - 26pp |
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Keywords |
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Abstract |
Using some of the latest cosmological data sets publicly available, we derive the strongest bounds in the literature on the sum of the three active neutrino masses, M-nu, within the assumption of a background flat Lambda CDM cosmology. In the most conservative scheme, combining Planck cosmic microwave background temperature anisotropies and baryon acoustic oscillations (BAO) data, as well as the up-to-date constraint on the optical depth to reionization (tau), the tightest 95% confidence level upper bound we find is M-nu < 0.151 eV. The addition of Planck high-l polarization data, which, however, might still be contaminated by systematics, further tightens the bound to M-nu < 0.118 eV. A proper model comparison treatment shows that the two aforementioned combinations disfavor the inverted hierarchy at similar to 64% C.L. and similar to 71% C.L., respectively. In addition, we compare the constraining power of measurements of the full- shape galaxy power spectrum versus the BAO signature, from the BOSS survey. Even though the latest BOSS full-shape measurements cover a larger volume and benefit from smaller error bars compared to previous similar measurements, the analysis method commonly adopted results in their constraining power still being less powerful than that of the extracted BAO signal. Our work uses only cosmological data; imposing the constraint M-nu > 0.06 eV from oscillations data would raise the quoted upper bounds by O(0.1 sigma) and would not affect our conclusions. |
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Address |
[Vagnozzi, Sunny; Freese, Katherine; Gerbino, Martina] Stockholm Univ, Dept Phys, Oskar Klein Ctr Cosmoparticle Phys, SE-10691 Stockholm, Sweden, Email: sunny.vagnozzi@fysik.su.se; |
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Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2470-0010 |
ISBN |
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Medium |
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Area |
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Conference |
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Notes |
WOS:000416948100004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3396 |
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