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Author  |
Escudero, M.; Hooper, D.; Krnjaic, G.; Pierre, M. |
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Title |
Cosmology with a very light Lmu – Ltau gauge boson |
Type |
Journal Article |
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Year |
2019 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
03 |
Issue |
3 |
Pages |
071 - 29pp |
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Keywords |
Cosmology of Theories beyond the SM; Beyond Standard Model; Neutrino Physics |
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Abstract |
In this paper, we explore in detail the cosmological implications of an abelian L – L gauge extension of the Standard Model featuring a light and weakly coupled Z. Such a scenario is motivated by the longstanding approximate to 4 sigma discrepancy between the measured and predicted values of the muon's anomalous magnetic moment, (g – 2), as well as the tension between late and early time determinations of the Hubble constant. If sufficiently light, the Z population will decay to neutrinos, increasing the overall energy density of radiation and altering the expansion history of the early universe. We identify two distinct regions of parameter space in this model in which the Hubble tension can be significantly relaxed. The first of these is the previously identified region in which a approximate to 10 – 20 MeV Z reaches equilibrium in the early universe and then decays, heating the neutrino population and delaying the process of neutrino decoupling. For a coupling of g (-) similar or equal to (3 – 8) x 10(-4), such a particle can also explain the observed (g – 2) anomaly. In the second region, the Z is very light (mZ approximate to 1eV to MeV) and very weakly coupled (g (-) approximate to 10(-13) to 10(-9)). In this case, the Z population is produced through freeze-in, and decays to neutrinos after neutrino decoupling. Across large regions of parameter space, we predict a contribution to the energy density of radiation that can appreciably relax the reported Hubble tension, N-eff similar or equal to 0.2. |
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Address |
[Escudero, Miguel] Kings Coll London, Dept Phys, London WC2R 2LS, England, Email: miguel.escudero@kcl.ac.uk; |
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Springer |
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English |
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ISSN |
1029-8479 |
ISBN |
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Expedition |
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Conference |
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Notes |
WOS:000461295500006 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3945 |
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Author |
Escudero, M.; Lopez-Pavon, J.; Rius, N.; Sandner, S. |
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Title |
Relaxing cosmological neutrino mass bounds with unstable neutrinos |
Type |
Journal Article |
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Year |
2020 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
12 |
Issue |
12 |
Pages |
119 - 44pp |
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Keywords |
Beyond Standard Model; Cosmology of Theories beyond the SM; Neutrino Physics |
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Abstract |
At present, cosmological observations set the most stringent bound on the neutrino mass scale. Within the standard cosmological model (Lambda CDM), the Planck collaboration reports Sigma m(v)< 0.12 eV at 95 % CL. This bound, taken at face value, excludes many neutrino mass models. However, unstable neutrinos, with lifetimes shorter than the age of the universe <tau>(nu) less than or similar to t(U), represent a particle physics avenue to relax this constraint. Motivated by this fact, we present a taxonomy of neutrino decay modes, categorizing them in terms of particle content and final decay products. Taking into account the relevant phenomenological bounds, our analysis shows that 2-body decaying neutrinos into BSM particles are a promising option to relax cosmological neutrino mass bounds. We then build a simple extension of the type I seesaw scenario by adding one sterile state nu (4) and a Goldstone boson phi, in which nu (i)-> nu (4)phi decays can loosen the neutrino mass bounds up to Sigma m(v) similar to 1 eV, without spoiling the light neutrino mass generation mechanism. Remarkably, this is possible for a large range of the right-handed neutrino masses, from the electroweak up to the GUT scale. We successfully implement this idea in the context of minimal neutrino mass models based on a U(1)(mu-tau) flavor symmetry, which are otherwise in tension with the current bound on Sigma m(v). |
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Address |
[Escudero, Miguel] Kings Coll London, Dept Phys, Theoret Particle Phys & Cosmol Grp, London WC2R 2LS, England, Email: miguel.escudero@kcl.ac.uk; |
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Publisher |
Springer |
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English |
Summary Language |
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Abbreviated Series Title |
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ISSN |
1029-8479 |
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Expedition |
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Conference |
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Notes |
WOS:000601400500005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4661 |
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Author |
Escudero, M.; Witte, S.J.; Rius, N. |
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Title |
The dispirited case of gauged U(1)(B-L) dark matter |
Type |
Journal Article |
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Year |
2018 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
08 |
Issue |
8 |
Pages |
190 - 30pp |
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Keywords |
Beyond Standard Model; Cosmology of Theories beyond the SM |
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Abstract |
We explore the constraints and phenomenology of possibly the simplest scenario that could account at the same time for the active neutrino masses and the dark matter in the Universe within a gauged U(1)(B-L) symmetry, namely right-handed neutrino dark matter. We find that null searches from lepton and hadron colliders require dark matter with a mass below 900 GeV to annihilate through a resonance. Additionally, the very strong constraints from high-energy dilepton searches fully exclude the model for 150 GeV < m(z') < 3 TeV. We further explore the phenomenology in the high mass region (i.e. masses greater than or similar to O(1) TeV) and highlight theoretical arguments, related to the appearance of a Landau pole or an instability of the scalar potential, disfavoring large portions of this parameter space. Collectively, these considerations illustrate that a minimal extension of the Standard Model via a local U(1)(B-L) symmetry with a viable thermal dark matter candidate is difficult to achieve without fine-tuning. We conclude by discussing possible extensions of the model that relieve tension with collider constraints by reducing the gauge coupling required to produce the correct relic abundance. |
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Address |
[Escudero, Miguel] Univ Valencia, CSIC, Dept Fis Teor, C Catedrat Jose Beltran 2, E-46980 Paterna, Spain, Email: Miguel.Escudero@ific.uv.es; |
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Springer |
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English |
Summary Language |
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Abbreviated Series Title |
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ISSN |
1029-8479 |
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Conference |
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Notes |
WOS:000443008100006 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
3706 |
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Author |
Fernandez-Martinez, E.; Lopez-Pavon, J.; Ota, T.; Rosauro-Alcaraz, S. |
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Title |
nu electroweak baryogenesis |
Type |
Journal Article |
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Year |
2020 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
10 |
Issue |
10 |
Pages |
063 - 28pp |
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Keywords |
Beyond Standard Model; Cosmology of Theories beyond the SM; CP viola- tion; Neutrino Physics |
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Abstract |
We investigate if the CP violation necessary for successful electroweak baryo- genesis may be sourced by the neutrino Yukawa couplings. In particular, we consider an electroweak scale Seesaw realization with sizable Yukawas where the new neutrino singlets form (pseudo)-Dirac pairs, as in the linear or inverse Seesaw variants. We find that the baryon asymmetry obtained strongly depends on how the neutrino masses vary within the bubble walls. Moreover, we also find that flavour effects critically impact the final asymmetry obtained and that, taking them into account, the observed value may be obtained in some regions of the parameter space. This source of CP violation naturally avoids the strong constraints from electric dipole moments and links the origin of the baryon asymmetry of the Universe with the mechanism underlying neutrino masses. Interestingly, the mixing of the active and heavy neutrinos needs to be sizable and could be probed at the LHC or future collider experiments. |
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Address |
[Fernandez-Martinez, E.; Ota, T.; Rosauro-Alcaraz, S.] Univ Autonoma Madrid, Dept Fis Teor, IFT UAM CSIC, Madrid 28049, Spain, Email: enrique.fernandez-martinez@uam.es; |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
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 |
1029-8479 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000582727900001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4582 |
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Author |
Fileviez Perez, P.; Murgui, C.; Plascencia, A.D. |
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Title |
Axion dark matter, proton decay and unification |
Type |
Journal Article |
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Year |
2020 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
01 |
Issue |
1 |
Pages |
091 - 18pp |
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Keywords |
Beyond Standard Model; Cosmology of Theories beyond the SM; GUT |
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Abstract |
We discuss the possibility to predict the QCD axion mass in the context of grand unified theories. We investigate the implementation of the DFSZ mechanism in the context of renormalizable SU(5) theories. In the simplest theory, the axion mass can be predicted with good precision in the range m(a) = (2-16) neV, and there is a strong correlation between the predictions for the axion mass and proton decay rates. In this context, we predict an upper bound for the proton decay channels with antineutrinos, tau(p -> K+(nu) over bar) less than or similar to 4 x 10(37) yr and tau(p -> pi(+)(nu) over bar) less than or similar to 2 x 10(36) yr. This theory can be considered as the minimal realistic grand unified theory with the DFSZ mechanism and it can be fully tested by proton decay and axion experiments. |
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Address |
[Fileviez Perez, Pavel; Plascencia, Alexis D.] Case Western Reserve Univ, Phys Dept, Cleveland, OH 44106 USA, Email: pxf112@case.edu; |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
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 |
1029-8479 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000588065200001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4605 |
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| Permanent link to this record |
