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Author Barenboim, G.; Chen, J.Z.; Hannestad, S.; Oldengott, I.M.; Tram, T.; Wong, Y.Y.Y.
Title Invisible neutrino decay in precision cosmology Type Journal Article
Year 2021 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 03 Issue 3 Pages 087 - 53pp
Keywords (up) cosmological neutrinos; neutrino properties; CMBR theory; cosmological parameters from CMBR
Abstract We revisit the topic of invisible neutrino decay in the precision cosmological context, via a first-principles approach to understanding the cosmic microwave background and large-scale structure phenomenology of such a non-standard physics scenario. Assuming an effective Lagrangian in which a heavier standard-model neutrino nu(H) couples to a lighter one nu(l) and a massless scalar particle phi via a Yukawa interaction, we derive from first principles the complete set of Boltzmann equations, at both the spatially homogeneous and the firstorder inhomogeneous levels, for the phase space densities of nu(H), nu(l), and phi in the presence of the relevant decay and inverse decay processes. With this set of equations in hand, we perform a critical survey of recent works on cosmological invisible neutrino decay in both limits of decay while nu(H) is ultra-relativistic and non-relativistic. Our two main findings are: (i) in the non-relativistic limit, the effective equations of motion used to describe perturbations in the neutrino-scalar system in the existing literature formally violate momentum conservation and gauge invariance, and (ii) in the ultra-relativistic limit, exponential damping of the anisotropic stress does not occur at the commonly-used rate Gamma(T) = (1/tau(0))( m(nu H)/E-nu H)(3), but at a rate similar to (1/ tau(0))(m(nu H)/E-nu H)(5). Both results are model-independent. The impact of the former finding on the cosmology of invisible neutrino decay is likely small. The latter, however, implies a significant revision of the cosmological limit on the neutrino lifetime tau(0) from tau(old)(0) greater than or similar to 1.2 x 10(9) s (m(nu H)/50 meV)(3) to tau(0) greater than or similar to (4 x 10(5) -> 4 x 10(6)) s (m(nu H)/50 meV)(5).
Address [Barenboim, Gabriela; Oldengott, Isabel M.] Univ Valencia, Dept Fis Teor, CSIC, Burjassot 46100, Spain, Email: gabriela.barenboim@uv.es;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1475-7516 ISBN Medium
Area Expedition Conference
Notes WOS:000636717400082 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4782
Permanent link to this record
 

 
Author Villaescusa-Navarro, F.; Bird, S.; Pena-Garay, C.; Viel, M.
Title Non-linear evolution of the cosmic neutrino background Type Journal Article
Year 2013 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 03 Issue 3 Pages 019 - 30pp
Keywords (up) cosmological neutrinos; neutrino properties; neutrino masses from cosmology
Abstract We investigate the non-linear evolution of the relic cosmic neutrino background by running large box-size, high resolution N-body simulations which incorporate cold dark matter (CDM) and neutrinos as independent particle species. Our set of simulations explore the properties of neutrinos in a reference Lambda CDM model with total neutrino masses between 0.05-0.60 eV in cold dark matter haloes of mass 10(11) – 10(15) h(-1) M-circle dot, over a redshift range z = 0 – 2. We compute the halo mass function and show that it is reasonably well fitted by the Sheth-Tormen formula, once the neutrino contribution to the total matter is removed. More importantly, we focus on the CDM and neutrino properties of the density and peculiar velocity fields in the cosmological volume, inside and in the outskirts of virialized haloes. The dynamical state of the neutrino particles depends strongly on their momentum: whereas neutrinos in the low velocity tail behave similarly to CDM particles, neutrinos in the high velocity tail are not affected by the clustering of the underlying CDM component. We find that the neutrino (linear) unperturbed momentum distribution is modified and mass and redshift dependent deviations from the expected Fermi-Dirac distribution are in place both in the cosmological volume and inside haloes. The neutrino density profiles around virialized haloes have been carefully investigated and a simple fitting formula is provided. The neutrino profile, unlike the cold dark matter one, is found to be cored with core size and central density that depend on the neutrino mass, redshift and mass of the halo, for halos of masses larger than similar to 10(13.5) h(-1) M-circle dot. For lower masses the neutrino profile is best fitted by a simple power-law relation in the range probed by the simulations. The results we obtain are numerically converged in terms of neutrino profiles at the 10% level for scales above similar to 200 h(-1) kpc at z = 0, and are stable with respect to box-size and starting redshift of the simulation. Our findings are particularly important in view of upcoming large-scale structure surveys, like Euclid, that are expected to probe the non-linear regime at the percent level with lensing and clustering observations.
Address INAF Osservatorio Astron Trieste, I-34143 Trieste, Italy, Email: villaescusa@oats.inaf.it;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1475-7516 ISBN Medium
Area Expedition Conference
Notes WOS:000316989200020 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1435
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Author Gariazzo, S.; Martinez-Mirave, P.; Mena, O.; Pastor, S.; Tortola, M.
Title Non-unitary three-neutrino mixing in the early Universe Type Journal Article
Year 2023 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 03 Issue 3 Pages 046 - 18pp
Keywords (up) cosmological neutrinos; neutrino properties; neutrino theory
Abstract Deviations from unitarity in the three-neutrino mixing canonical picture are expected in many physics scenarios beyond the Standard Model. The mixing of new heavy neutral leptons with the three light neutrinos would in principle modify the strength and flavour structure of charged-current and neutral-current interactions with matter. Non-unitarity effects would therefore have an impact on the neutrino decoupling processes in the early Universe and on the value of the effective number of neutrinos, Neff. We calculate the cosmological energy density in the form of radiation with a non-unitary neutrino mixing matrix, addressing the possible interplay between parameters. Highly accurate measurements of Neff from forthcoming cosmological observations can provide independent and complementary limits on the departures from unitarity. For completeness, we relate the scenario of small deviations from unitarity to non-standard neutrino interactions and compare the forecasted constraints to other existing limits in the literature.
Address [Gariazzo, Stefano] INFN, Sez Torino, Via P Giuria 1, I-10125 Turin, Italy, Email: gariazzo@to.infn.it;
Corporate Author Thesis
Publisher IOP Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1475-7516 ISBN Medium
Area Expedition Conference
Notes WOS:000959757500008 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5516
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Author Di Valentino, E.; Melchiorri, A.; Mena, O.
Title Dark radiation sterile neutrino candidates after Planck data Type Journal Article
Year 2013 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 11 Issue 11 Pages 018 - 13pp
Keywords (up) cosmological neutrinos; neutrino properties; neutrino theory; dark energy theory
Abstract Recent Cosmic Microwave Background (CMB) results from the Planck satellite, combined with previous CMB data and Hubble constant measurements from the Hubble Space Telescope, provide a constraint on the effective number of relativistic degrees of freedom 3.62(-0.48)(+0.50) at 95% CL. New Planck data provide a unique opportunity to place limits on models containing relativistic species at the decoupling epoch. We present here the bounds on sterile neutrino models combining Planck data with galaxy clustering information. Assuming N-eff active plus sterile massive neutrino species, in the case of a Planck+WP+HighL+HST analysis we find m(nu,sterile)(eff) < 0.36 eV and 3.14 < N-eff < 4.15 at 95% CL, while using Planck+WP+HighL data in combination with the full shape of the galaxy power spectrum from the Baryon Oscillation Spectroscopic Survey BOSS Data Relase 9 measurements, we find that 3.30 < N-eff < 4.43 and m(nu,sterile)(eff) < 0.33 eV both at 95% CL with the three active neutrinos having the minimum mass allowed in the normal hierarchy scheme, i.e. Sigma m(nu) similar to 0.06 eV. These values compromise the viability of the (3 + 2) massive sterile neutrino models for the parameter region indicated by global fits of neutrino oscillation data. Within the (3 + 1) massive sterile neutrino scenario, we find m(nu,sterile)(eff) < 0.34 eV at 95% CL. While the existence of one extra sterile massive neutrino state is compatible with current oscillation data, the values for the sterile neutrino mass preferred by oscillation analyses are significantly higher than the current cosmological bound. We review as well the bounds on extended dark sectors with additional light species based on the latest Planck CMB observations.
Address [Di Valentino, Eleonora; Melchiorri, Alessandro] Univ Roma La Sapienza, Dept Phys, I-00185 Rome, Italy, Email: eleonora.divalentino@roma1.infn.it;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1475-7516 ISBN Medium
Area Expedition Conference
Notes WOS:000327843900019 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1672
Permanent link to this record
 

 
Author Gariazzo, S.; de Salas, P.F.; Pastor, S.
Title Thermalisation of sterile neutrinos in the early universe in the 3+1 scheme with full mixing matrix Type Journal Article
Year 2019 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 07 Issue 7 Pages 014 - 30pp
Keywords (up) cosmological neutrinos; neutrino properties; particle physics – cosmology connection; physics of the early universe
Abstract In the framework of a 3+1 scheme with an additional inert state, we consider the thermalisation of sterile neutrinos in the early Universe taking into account the full 4 x 4 mixing matrix. The evolution of the neutrino energy distributions is found solving the momentum-dependent kinetic equations with full diagonal collision terms, as in previous analyses of flavour neutrino decoupling in the standard case. The degree of thermalisation of the sterile state is shown in terms of the effective number of neutrinos, N-eff, and its dependence on the three additional mixing angles (theta(14), theta(24), theta(34)) and on the squared mass difference Delta m(41)(2) is discussed. Our results are relevant for fixing the contribution of a fourth light neutrino species to the cosmological energy density, whose value is very well constrained by the final Planck analysis. For the preferred region of active-sterile mixing parameters from short-baseline neutrino experiments, we find that the fourth state is fully thermalised (N-eff similar or equal to 4).
Address [Gariazzo, S.; Pastor, S.] Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain, Email: gariazzo@ific.uv.es;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1475-7516 ISBN Medium
Area Expedition Conference
Notes WOS:000474782100001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4076
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Author Bennett, J.J.; Buldgen, G.; de Salas, P.F.; Drewes, M.; Gariazzo, S.; Pastor, S.; Wong, Y.Y.Y.
Title Towards a precision calculation of the effective number of neutrinos N-eff in the Standard Model. Part II. Neutrino decoupling in the presence of flavour oscillations and finite-temperature QED Type Journal Article
Year 2021 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 04 Issue 4 Pages 073 - 33pp
Keywords (up) cosmological neutrinos; neutrino properties; particle physics – cosmology connection; physics of the early universe
Abstract We present in this work a new calculation of the standard-model benchmark value for the effective number of neutrinos, N-eff(SM), that quantifies the cosmological neutrinoto-photon energy densities. The calculation takes into account neutrino flavour oscillations, finite-temperature effects in the quantum electrodynamics plasma to O(e(3)), where e is the elementary electric charge, and a full evaluation of the neutrino-neutrino collision integral. We provide furthermore a detailed assessment of the uncertainties in the benchmark N(eff)(SM )value, through testing the value's dependence on (i) optional approximate modelling of the weak collision integrals, (ii) measurement errors in the physical parameters of the weak sector, and (iii) numerical convergence, particularly in relation to momentum discretisation. Our new, recommended standard-model benchmark is N-eff(SM) 3.0440 +/- 0.0002, where the nominal uncertainty is attributed predominantly to errors incurred in the numerical solution procedure (vertical bar delta N-eff vertical bar similar to 10(-4)), augmented by measurement errors in the solar mixing angle sin(2) theta(12) (vertical bar delta N-eff vertical bar similar to 10(-4)).
Address [Bennett, Jack J.; Wong, Yvonne Y. Y.] Univ New South Wales, Sch Phys, Sydney Consortium Particle Phys & Cosmol, Sydney, NSW 2052, Australia, Email: j.j.bennett@unsw.edu.au;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1475-7516 ISBN Medium
Area Expedition Conference
Notes WOS:000647827600001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4827
Permanent link to this record
 

 
Author Jeong, Y.S.; Palomares-Ruiz, S.; Reno, M.H.; Sarcevic, I.
Title Probing secret interactions of eV-scale sterile neutrinos with the diffuse supernova neutrino background Type Journal Article
Year 2018 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 06 Issue 6 Pages 019 - 43pp
Keywords (up) cosmological neutrinos; neutrino theory; supernova neutrinos
Abstract Sterile neutrinos with mass in the eV-scale and large mixings of order theta(0) similar or equal to 0.1 could explain some anomalies found in short-baseline neutrino oscillation data. Here, we revisit a neutrino portal scenario in which eV-scale sterile neutrinos have self-interactions via a new gauge vector boson phi. Their production in the early Universe via mixing with active neutrinos can be suppressed by the induced effective potential in the sterile sector. We study how different cosmological observations can constrain this model, in terms of the mass of the new gauge boson, M-phi, and its coupling to sterile neutrinos, g(s). Then, we explore how to probe part of the allowed parameter space of this particular model with future observations of the diffuse supernova neutrino background by the Hyper-Kamiokande and DUNE detectors. For M-phi similar to 5 – 10 keV and g(s) similar to 10-(4) – 10(-2), as allowed by cosmological constraints, we find that interactions of diffuse supernova neutrinos with relic sterile neutrinos on their way to the Earth would result in significant dips in the neutrino spectrum which would produce unique features in the event spectra observed in these detectors.
Address [Jeong, Yu Seon; Sarcevic, Ina] Univ Arizona, Dept Phys, 1118 E 4th St, Tucson, AZ 85704 USA, Email: ysjeong@email.arizona.edu;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1475-7516 ISBN Medium
Area Expedition Conference
Notes WOS:000434991300006 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3613
Permanent link to this record
 

 
Author de Salas, P.F.; Pastor, S.
Title Relic neutrino decoupling with flavour oscillations revisited Type Journal Article
Year 2016 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 07 Issue 7 Pages 051 - 18pp
Keywords (up) cosmological neutrinos; particle physics – cosmology connection; physics of the; early universe; neutrino properties
Abstract We study the decoupling process of neutrinos in the early universe in the presence of three-flavour oscillations. The evolution of the neutrino spectra is found by solving the corresponding momentum-dependent kinetic equations for the neutrino density matrix, including for the first time the proper collision integrals for both diagonal and off-diagonal elements. This improved calculation modifies the evolution of the off-diagonal elements of the neutrino density matrix and changes the deviation from equilibrium of the frozen neutrino spectra. However, it does not vary the contribution of neutrinos to the cosmological energy density in the form of radiation, usually expressed in terms of the effective number of neutrinos, N-eff. We find a value of N-eff = 3.045, in agreement with previous theoretical calculations and consistent with the latest analysis of Planck data. This result does not depend on the ordering of neutrino masses. We also consider the effect of non-standard neutrino-electron interactions (NSI), predicted in many theoretical models where neutrinos acquire mass. For two sets of NSI parameters allowed by present data, we find that Neff can be reduced down to 3.040 or enhanced up to 3.059.
Address [de Salas, Pablo F.; Pastor, Sergio] Univ Valencia, CSIC, Inst Fis Corpuscular, Parc Cient UV,C Catedrat Jose Beltran 2, E-46980 Paterna, Valencia, Spain, Email: pabrerde@ific.uv.es;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1475-7516 ISBN Medium
Area Expedition Conference
Notes WOS:000381830000052 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 2784
Permanent link to this record
 

 
Author Barenboim, G.; Park, W.I.
Title Lepton number asymmetries and the lower bound on the reheating temperature Type Journal Article
Year 2017 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 12 Issue 12 Pages 037 - 13pp
Keywords (up) cosmological neutrinos; physics of the early universe
Abstract We show that the reheating temperature of a matter-domination era in the early universe can be pushed down to the neutrino decoupling temperature at around 2 MeV if the reheating takes place through non-hadronic decays of the dominant matter and neutrino-antineutrino asymmetries are still large enough, vertical bar L vertical bar greater than or similar to O(10(-2)) (depending on the neutrino flavor) at the end of reheating.
Address [Barenboim, Gabriela] Univ Valencia, Dept Fis Teor, CSIC, E-46100 Burjassot, Spain, Email: Gabriela.Barenboim@uv.es;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1475-7516 ISBN Medium
Area Expedition Conference
Notes WOS:000418672700001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3430
Permanent link to this record
 

 
Author Pena-Garay, C.; Verde, L.; Jimenez, R.
Title Neutrino footprint in large scale structure Type Journal Article
Year 2017 Publication Physics of the Dark Universe Abbreviated Journal Phys. Dark Universe
Volume 15 Issue Pages 31-34
Keywords (up) Cosmology; Neutrinos; Large scale structure
Abstract Recent constrains on the sum of neutrino masses inferred by analyzing cosmological data, show that detecting a non-zero neutrino mass is within reach of forthcoming cosmological surveys. Such a measurement will imply a direct determination of the absolute neutrino mass scale. Physically, the measurement relies on constraining the shape of the matter power spectrum below the neutrino free streaming scale: massive neutrinos erase power at these scales. However, detection of a lack of small-scale power from cosmological data could also be due to a host of other effects. It is therefore of paramount importance to validate neutrinos as the source of power suppression at small scales. We show that, independent on hierarchy, neutrinos always show a footprint on large, linear scales; the exact location and properties are fully specified by the measured power suppression (an astrophysical measurement) and atmospheric neutrinos mass splitting (a neutrino oscillation experiment measurement). This feature cannot be easily mimicked by systematic uncertainties in the cosmological data analysis or modifications in the cosmological model. Therefore the measurement of such a feature, up to 1% relative change in the power spectrum for extreme differences in the mass eigenstates mass ratios, is a smoking gun for confirming the determination of the absolute neutrino mass scale from cosmological observations. It also demonstrates the synergy between astrophysics and particle physics experiments.
Address [Verde, Licia; Jimenez, Raul] Univ Barcelona, ICREA, Marti & Franques 1, E-08028 Barcelona, Spain, Email: liciaverde@gmail.com
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2212-6864 ISBN Medium
Area Expedition Conference
Notes WOS:000401825700003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3138
Permanent link to this record