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Author Vincent, A.C.; Fernandez Martinez, E.; Hernandez, P.; Mena, O.; Lattanzi, M. url  doi
openurl 
  Title Revisiting cosmological bounds on sterile neutrinos Type Journal Article
  Year 2015 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.  
  Volume 04 Issue 4 Pages 006 - 23pp  
  Keywords (down) particle physics – cosmology connection; cosmological neutrinos; cosmology of theories beyond the SM  
  Abstract We employ state-of-the art cosmological observables including supernova surveys and BAO information to provide constraints on the mass and mixing angle of a non-resonantly produced sterile neutrino species, showing that cosmology can effectively rule out sterile neutrinos which decay between BBN and the present day. The decoupling of an additional heavy neutrino species can modify the time dependence of the Universe's expansion between BBN and recombination and, in extreme cases, lead to an additional matter-dominated period; while this could naively lead to a younger Universe with a larger Hubble parameter, it could later be compensated by the extra radiation expected in the form of neutrinos from sterile decay. However, recombination-era observables including the Cosmic Microwave Background (CMB), the shift parameter R-CMB and the sound horizon r(s) from Baryon Acoustic Oscillations (BAO) severely constrain this scenario. We self-consistently include the full time-evolution of the coupled sterile neutrino and standard model sectors in an MCMC, showing that if decay occurs after BBN, the sterile neutrino is essentially bounded by the constraint sin(2) theta less than or similar to 0.026(m(s)/eV)(-2).  
  Address [Vincent, Aaron C.] Univ Durham, Dept Phys, IPPP, Durham DH1 3LE, England, Email: aaron.vincent@durham.ac.uk;  
  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:000355742500007 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2261  
Permanent link to this record
 

 
Author Oldengott, I.M.; Barenboim, G.; Kahlen, S.; Salvado, J.; Schwarz, D.J. url  doi
openurl 
  Title How to relax the cosmological neutrino mass bound Type Journal Article
  Year 2019 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.  
  Volume 04 Issue 4 Pages 049 - 18pp  
  Keywords (down) neutrino masses from cosmology; cosmological neutrinos; cosmological parameters from CMBR; cosmological parameters from LSS  
  Abstract We study the impact of non-standard momentum distributions of cosmic neutrinos on the anisotropy spectrum of the cosmic microwave background and the matter power spectrum of the large scale structure. We show that the neutrino distribution has almost no unique observable imprint, as it is almost entirely degenerate with the effective number of neutrino flavours, N-eff, and the neutrino mass, m(nu). Performing a Markov chain Monte Carlo analysis with current cosmological data, we demonstrate that the neutrino mass bound heavily depends on the assumed momentum distribution of relic neutrinos. The message of this work is simple and has to our knowledge not been pointed out clearly before: cosmology allows that neutrinos have larger masses if their average momentum is larger than that of a perfectly thermal distribution. Here we provide an example in which the mass limits are relaxed by a factor of two.  
  Address [Oldengott, Isabel M.; Barenboim, Gabriela] Univ Valencia, Dept Fis Teor, CSIC, E-46100 Burjassot, Spain, Email: isabel.oldengott@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:000466578400003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4001  
Permanent link to this record
 

 
Author Farzan, Y.; Palomares-Ruiz, S. url  doi
openurl 
  Title Dips in the diffuse supernova neutrino background Type Journal Article
  Year 2014 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.  
  Volume 06 Issue 6 Pages 014 - 21pp  
  Keywords (down) dark matter theory; supernova neutrinos; cosmological neutrinos  
  Abstract Scalar (fermion) dark matter with mass in the MeV range coupled to ordinary neutrinos and another fermion (scalar) is motivated by scenarios that establish a link between radiatively generated neutrino masses and the dark matter relic density. With such a coupling, cosmic supernova neutrinos, on their way to us, could resonantly interact with the background (lark matter particles, giving rise to a dip in their redshift-integrated spectra. Current and future neutrino detectors, such as Super-Kamiokande. LENA and HyperKamiokande, could be able to detect this distortion.  
  Address [Farzan, Yasaman] Inst Res Fundamental Sci IPM, Sch Phys, Tehran, Iran, Email: yasaman@theory.ipm.ac.ir;  
  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:000346407200014 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2046  
Permanent link to this record
 

 
Author Moline, A.; Ibarra, A.; Palomares-Ruiz, S. url  doi
openurl 
  Title Future sensitivity of neutrino telescopes to dark matter annihilations from the cosmic diffuse neutrino signal Type Journal Article
  Year 2015 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.  
  Volume 06 Issue 6 Pages 005 - 34pp  
  Keywords (down) dark matter theory; dark matter simulations; cosmological neutrinos  
  Abstract Cosmological observations and cold dark matter N-body simulations indicate that our Universe is populated by numerous halos, where dark matter particles annihilate, potentially producing Standard Model particles. In this paper we calculate the contribution to the diffuse neutrino background from dark matter annihilations in halos at all redshifts and we estimate the future sensitivity to the annihilation cross section of neutrino telescopes such as IceCube or ANTARES. We consider various parametrizations to describe the internal halo properties and for the halo mass function in order to bracket the theoretical uncertainty in the limits from the modeling of the cosmological annihilation flux. We find that observations of the cosmic diffuse neutrino flux at large angular distances from the galactic center lead to constraints on the dark matter annihilation cross section which are complementary to ( and for some extrapolations of the astrophysical parameters, better than) those stemming from observations of the Milky Way halo, especially for neutrino telescopes not pointing directly to the Milky Way center, as is the case of IceCube.  
  Address [Moline, Angeles] Univ Tecn Lisboa, Inst Super Tecn, CFTP, P-1049001 Lisbon, Portugal, Email: maria.moline@ist.utl.pt;  
  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:000359215400006 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2369  
Permanent link to this record
 

 
Author Barenboim, G.; Park, W.I. url  doi
openurl 
  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 (down) 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 de Salas, P.F.; Pastor, S. url  doi
openurl 
  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 (down) 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 Jeong, Y.S.; Palomares-Ruiz, S.; Reno, M.H.; Sarcevic, I. url  doi
openurl 
  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 (down) 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 Gariazzo, S.; de Salas, P.F.; Pastor, S. url  doi
openurl 
  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 (down) 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  
Permanent link to this record
 

 
Author Bennett, J.J.; Buldgen, G.; de Salas, P.F.; Drewes, M.; Gariazzo, S.; Pastor, S.; Wong, Y.Y.Y. url  doi
openurl 
  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 (down) 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 Di Valentino, E.; Melchiorri, A.; Mena, O. url  doi
openurl 
  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 (down) 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  
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