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Author |
Caputo, A.; Hernandez, P.; Lopez-Pavon, J.; Salvado, J. |
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Title |
The seesaw portal in testable models of neutrino masses |
Type |
Journal Article |
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Year |
2017 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
06 |
Issue |
6 |
Pages |
112 - 20pp |
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Keywords |
Beyond Standard Model; Neutrino Physics |
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Abstract |
A Standard Model extension with two Majorana neutrinos can explain the measured neutrino masses and mixings, and also account for the matter-antimatter asymmetry in a region of parameter space that could be testable in future experiments. The testability of the model relies to some extent on its minimality. In this paper we address the possibility that the model might be extended by extra generic new physics which we parametrize in terms of a low-energy effective theory. We consider the effects of the operators of the lowest dimensionality, d = 5, and evaluate the upper bounds on the coefficients so that the predictions of the minimal model are robust. One of the operators gives a new production mechanism for the heavy neutrinos at LHC via higgs decays. The higgs can decay to a pair of such neutrinos that, being long-lived, leave a powerful signal of two displaced vertices. We estimate the LHC reach to this process. |
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Address |
[Caputo, A.; Hernandez, P.; Salvado, J.] Univ Valencia, Inst Fis Corpusc, Catedrat Jose Beltran 2, Valencia 46980, Spain, Email: andrea.caputo@cern.ch; |
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Springer |
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English |
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ISSN |
1029-8479 |
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Conference |
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Notes |
WOS:000404625300005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3196 |
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Permanent link to this record |
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Author |
Caputo, A.; Hernandez, P.; Kekic, M.; Lopez-Pavon, J.; Salvado, J. |
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Title |
The seesaw path to leptonic CP violation |
Type |
Journal Article |
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Year |
2017 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
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Volume |
77 |
Issue |
4 |
Pages |
258 - 7pp |
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Keywords |
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Abstract |
Future experiments such as SHiP and highintensity e(+)e(-) colliders will have a superb sensitivity to heavy Majorana neutrinos with masses below M-Z. We show that the measurement of the mixing to electrons and muons of one such state could establish the existence of CP violating phases in the neutrino mixing matrix, in the context of low-scale seesaw models. We quantify in the minimal model the CP reach of these future experiments, and demonstrate that CP violating phases in the mixing matrix could be established at 5 sigma CL in a very significant fraction of parameter space. |
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Address |
[Caputo, A.; Hernandez, P.; Kekic, M.; Salvado, J.] Univ Valencia, Inst Fis Corpuscular, Edificio Inst Invest,Catedrat Jose Beltran 2, Paterna 46980, Spain, Email: andrea.caputo@cern.ch; |
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Springer |
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English |
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ISSN |
1434-6044 |
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Conference |
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Notes |
WOS:000400079300002 |
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no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3111 |
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Author |
Abdullahi, A.M. et al; Lopez-Pavon, J. |
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Title |
The present and future status of heavy neutral leptons |
Type |
Journal Article |
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Year |
2023 |
Publication |
Journal of Physics G |
Abbreviated Journal |
J. Phys. G |
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Volume |
50 |
Issue |
2 |
Pages |
020501 - 100pp |
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Keywords |
Neutrinos; beyond the standard model; sterile neutrinos |
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Abstract |
The existence of nonzero neutrino masses points to the likely existence of multiple Standard Model neutral fermions. When such states are heavy enough that they cannot be produced in oscillations, they are referred to as heavy neutral leptons (HNLs). In this white paper, we discuss the present experimental status of HNLs including colliders, beta decay, accelerators, as well as astrophysical and cosmological impacts. We discuss the importance of continuing to search for HNLs, and its potential impact on our understanding of key fundamental questions, and additionally we outline the future prospects for next-generation future experiments or upcoming accelerator run scenarios. |
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Address |
[Abdullahi, Asli M.; Plestid, Ryan] Fermilab Natl Accelerator Lab, Theoret Phys Dept, POB 500, Batavia, IL 60510 USA, Email: shoemaker@vt.edu |
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Publisher |
IOP Publishing Ltd |
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Language |
English |
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ISSN |
0954-3899 |
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Conference |
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Notes |
WOS:000918351600001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5486 |
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Permanent link to this record |
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Author |
Donini, A.; Hernandez, P.; Lopez-Pavon, J.; Maltoni, M.; Schwetz, T. |
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Title |
The minimal 3+2 neutrino model versus oscillation anomalies |
Type |
Journal Article |
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Year |
2012 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
07 |
Issue |
7 |
Pages |
161 - 20pp |
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Keywords |
Neutrino Physics; Beyond Standard Model |
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Abstract |
We study the constraints imposed by neutrino oscillation experiments on the minimal extension of the Standard Model that can explain neutrino masses, which requires the addition of just two singlet Weyl fermions. The most general renormalizable couplings of this model imply generically four massive neutrino mass eigenstates while one remains massless: it is therefore a minimal 3+2 model. The possibility to account for the confirmed solar, atmospheric and long-baseline oscillations, together with the LSND/MiniBooNE and reactor anomalies is addressed. We find that the minimal model can fit oscillation data including the anomalies better than the standard 3 nu model and similarly to the 3 + 2 phenomenological models, even though the number of free parameters is much smaller than in the latter. Accounting for the anomalies in the minimal model favours a normal hierarchy of the light states and requires a large reactor angle, in agreement with recent measurements. Our analysis of the model employs a new parametrization of seesaw models that extends the Casas-Ibarra one to regimes where higher order corrections in the light-heavy mixings are significant. |
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Address |
[Donini, A.; Hernandez, P.] Univ Valencia, Inst Fis Corpuscular, CSIC, E-46071 Valencia, Spain, Email: andrea.donini@uam.es; |
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Publisher |
Springer |
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Language |
English |
Summary Language |
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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 |
1126-6708 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000307299800039 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1161 |
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Permanent link to this record |
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Author |
Hernandez, P.; Kekic, M.; Lopez-Pavon, J.; Racker, J.; Salvado, J. |
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Title |
Testable baryogenesis is in seesaw models |
Type |
Journal Article |
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Year |
2016 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
08 |
Issue |
8 |
Pages |
157 - 29pp |
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Keywords |
Cosmology of Theories beyond the SM; CP violation; Neutrino Physics; Beyond Standard Model |
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Abstract |
We revisit the production of baryon asymmetries in the minimal type I seesaw model with heavy Majorana singlets in the GeV range. In particular we include “washout” effects from scattering processes with gauge bosons, Higgs decays and inverse decays, besides the dominant top scatterings. We show that in the minimal model with two singlets, and for an inverted light neutrino ordering, future measurements from SHiP and neutrinoless double beta decay could in principle provide sufficient information to predict the matter-antimatter asymmetry in the universe. We also show that SHiP measurements could provide very valuable information on the PMNS CP phases. |
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Address |
[Hernandez, P.; Kekic, M.; Racker, J.; Salvado, J.] Univ Valencia, Inst Fis Corpuscular, Edificio Inst Invest,Catedrat Jose Beltran 2, Valencia 46980, Spain, Email: m.pilar.hernandez@uv.es; |
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Publisher |
Springer |
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Language |
English |
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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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Area |
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Expedition |
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Conference |
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Notes |
WOS:000382398000004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2787 |
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Permanent link to this record |
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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 |
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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Area |
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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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Permanent link to this record |
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Author |
Sandner, S.; Hernandez, P.; Lopez-Pavon, J.; Rius, N. |
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Title |
Predicting the baryon asymmetry with degenerate right-handed neutrinos |
Type |
Journal Article |
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Year |
2023 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
11 |
Issue |
11 |
Pages |
153 - 37pp |
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Keywords |
Baryo-and Leptogenesis; Sterile or Heavy Neutrinos; Early Universe Particle Physics |
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Abstract |
We consider the generation of a baryon asymmetry in an extension of the Standard Model with two singlet Majorana fermions that are degenerate above the electroweak phase transition. The model can explain neutrino masses as well as the observed matter-antimatter asymmetry, for masses of the heavy singlets below the electroweak scale. The only physical CP violating phases in the model are those in the PMNS mixing matrix, i.e. the Dirac phase and a Majorana phase that enter light neutrino observables. We present an accurate analytic approximation for the baryon asymmetry in terms of CP flavour invariants, and derive the correlations with neutrino observables. We demonstrate that the measurement of CP violation in neutrino oscillations as well as the mixings of the heavy neutral leptons with the electron, muon and tau flavours suffice to pin down the matter-antimatter asymmetry from laboratory measurements. |
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Address |
[Sandner, S.] Univ Valencia, Inst Fis Corpuscular, Edificio Inst Invest,Catedrat Jose Beltran 2, Paterna 46980, Spain, Email: stefan.sandner@ific.uv.es; |
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Publisher |
Springer |
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English |
Summary Language |
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ISSN |
1029-8479 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:001111979900002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
5869 |
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Permanent link to this record |
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Author |
Hernandez, P.; Kekic, M.; Lopez-Pavon, J. |
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Title |
N_eff in low-scale seesaw models versus the lightest neutrino mass |
Type |
Journal Article |
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Year |
2014 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
90 |
Issue |
6 |
Pages |
065033 - 12pp |
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Keywords |
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Abstract |
We evaluate the contribution to N_eff of the extra sterile states in low-scale type I seesaw models (with three extra sterile states). We explore the full parameter space and find that at least two of the heavy states always reach thermalization in the early Universe, while the third one might not thermalize provided the lightest neutrino mass is below O(10(-3) eV). Constraints from cosmology therefore severely restrict the spectra of heavy states in the range 1 eV-100 MeV. The implications for neutrinoless double beta decay are also discussed. |
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Address |
[Hernandez, P.; Kekic, M.] Univ Valencia, IFIC CSIC, E-46071 Valencia, Spain, Email: m.pilar.hernandez@uv.es; |
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Publisher |
Amer Physical Soc |
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Language |
English |
Summary Language |
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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 |
1550-7998 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000344108100004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2001 |
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Permanent link to this record |
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Author |
Fernandez-Martinez, E.; Lopez-Pavon, J.; No, J.M.; Ota, T.; Rosauro-Alcaraz, S. |
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Title |
nu Electroweak baryogenesis: the scalar singlet strikes back |
Type |
Journal Article |
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Year |
2023 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
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Volume |
83 |
Issue |
8 |
Pages |
715 - 23pp |
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Keywords |
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Abstract |
We perform a comprehensive scan of the parameter space of a general singlet scalar extension of the Standard Model to identify the regions which can lead to a strong first-order phase transition, as required by the electroweak baryogenesis mechanism. We find that taking into account bubble nucleation is a fundamental constraint on the parameter space and present a conservative and fast estimate for it so as to enable efficient parameter space scanning. The allowed regions turn out to be already significantly probed by constraints on the scalar mixing from Higgs signal strength measurements. We also consider the addition of new neutrino singlet fields with Yukawa couplings to both scalars and forming heavy (pseudo)-Dirac pairs, as in the linear or inverse Seesaw mechanisms for neutrino mass generation. We find that their inclusion does not alter the allowed parameter space from early universe phenomenology in a significant way. Conversely, there are allowed regions of the parameter space where the presence of the neutrino singlets would remarkably modify the collider phenomenology, yielding interesting new signatures in Higgs and singlet scalar decays. |
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Address |
[Fernandez-Martinez, E.; No, J. M.; Ota, T.] Univ Autonoma Madrid, CSIC, Dept Fis Teor, IFT UAM, Madrid 28049, Spain, Email: rosauro@ijclab.in2p3.fr |
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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 |
1434-6044 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:001045200700003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5609 |
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Permanent link to this record |
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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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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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Permanent link to this record |