| Records |
| Author |
Escudero, M.; Hooper, D.; Krnjaic, G.; Pierre, M. |
| Title |
Cosmology with a very light Lmu – Ltau gauge boson |
Type |
Journal Article |
| Year |
2019 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
Volume  |
03 |
Issue |
3 |
Pages |
071 - 29pp |
| Keywords |
Cosmology of Theories beyond the SM; Beyond Standard Model; Neutrino Physics |
| 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. |
| Address |
[Escudero, Miguel] Kings Coll London, Dept Phys, London WC2R 2LS, England, Email: miguel.escudero@kcl.ac.uk; |
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Thesis |
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| Publisher |
Springer |
Place of Publication |
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| Language |
English |
Summary Language |
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| Series Editor |
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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:000461295500006 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3945 |
| Permanent link to this record |
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| Author |
Bernabeu, J.; Segarra, A. |
| Title |
Do T asymmetries for neutrino oscillations in uniform matter have a CP-even component? |
Type |
Journal Article |
| Year |
2019 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
03 |
Issue |
3 |
Pages |
103 - 12pp |
| Keywords |
CP violation; Discrete Symmetries; Neutrino Physics |
| Abstract |
Observables of neutrino oscillations in matter have, in general, contributions from the effective matter potential. It contaminates the CP violation asymmetry adding a fake effect that has been recently disentangled from the genuine one by their different behavior under T and CPT. Is the genuine T-odd CPT-invariant component of the CP asymmetry coincident with the T asymmetry? Contrary to CP, matter effects in uniform matter cannot induce by themselves a non-vanishing T asymmetry; however, the question of the title remained open. We demonstrate that, in the presence of genuine CP violation, there is a new non-vanishing CP-even, and so CPT-odd, component in the T asymmetry in matter, which is of odd-parity in both the phase delta of the flavor mixing and the matter parameter a. The two disentangled components, genuine A(alpha beta)(T;CP) and fake A(alpha beta)(T;CPT), could be experimentally separated by the measurement of the two T asymmetries in matter (nu(alpha) <-> nu(beta)) and ((nu) over bar <-> (nu) over bar (beta)). For the (nu(mu) <-> nu(e)) transitions, the energy dependence of the new A(mu e)(T;CPT) component is like the matter-induced term A(mu e)(CP;CPT) of the CP asymmetry which is odd under a change of the neutrino mass hierarchy. We have thus completed the physics involved in all observable asymmetries in matter by means of their disentanglement into the three independent components, genuine A(alpha beta)(CP;T) and fake A(alpha beta)(CP;CPT) and A(alpha beta)(T;CPT). |
| Address |
[Bernabeu, Jose] Univ Valencia, Dept Fis Teor, CSIC, E-46100 Valencia, Spain, Email: Jose.Bernabeu@uv.es; |
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Thesis |
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| Publisher |
Springer |
Place of Publication |
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| Language |
English |
Summary Language |
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Abbreviated Series Title |
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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:000462327100001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
3961 |
| Permanent link to this record |
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| Author |
Barenboim, G.; Martinez-Mirave, P.; Ternes, C.A.; Tortola, M. |
| Title |
Sterile neutrinos with altered dispersion relations revisited |
Type |
Journal Article |
| Year |
2020 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
03 |
Issue |
3 |
Pages |
070 - 18pp |
| Keywords |
Beyond Standard Model; Neutrino Physics |
| Abstract |
In this paper we investigate neutrino oscillations with altered dispersion relations in the presence of sterile neutrinos. Modified dispersion relations represent an agnostic way to parameterize new physics. Models of this type have been suggested to explain global neutrino oscillation data, including deviations from the standard three-neutrino paradigm as observed by a few experiments. We show that, unfortunately, in this type of models new tensions arise turning them incompatible with global data. |
| Address |
[Barenboim, G.; Martinez-Mirave, P.; Ternes, C. A.; Tortola, M.] Univ Valencia, CSIC, Inst Fis Corpuscular, C Catedrat Jose Beltran 2, Paterna 46980, Spain, Email: Gabriela.Barenboim@uv.es; |
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| Publisher |
Springer |
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English |
Summary Language |
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Abbreviated Series Title |
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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:000520538500003 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
4333 |
| Permanent link to this record |
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| Author |
Barducci, D.; Bertuzzo, E.; Caputo, A.; Hernandez, P.; Mele, B. |
| Title |
The see-saw portal at future Higgs Factories |
Type |
Journal Article |
| Year |
2021 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
03 |
Issue |
3 |
Pages |
117 - 32pp |
| Keywords |
Beyond Standard Model; Higgs Physics; Neutrino Physics |
| Abstract |
We consider an extension of the Standard Model with two right-handed singlet fermions with mass at the electroweak scale that induce neutrino masses, plus a generic new physics sector at a higher scale Lambda. We focus on the effective operators of lowest dimension d = 5, which induce new production and decay modes for the singlet fermions. We assess the sensitivity of future Higgs Factories, such as FCC-ee, CLIC-380, ILC and CEPC, to the coefficients of these operators for various center of mass energies. We show that future lepton colliders can test the cut-off of the theory up to Lambda similar or equal to 500-1000 TeV, surpassing the reach of future indirect measurements of the Higgs and Z boson widths. We also comment on the possibility of determining the underlying model flavor structure should a New Physics signal be observed, and on the impact of higher dimensional d = 6 operators on the experimental signatures. |
| Address |
[Barducci, Daniele] Univ Roma Sapienza, Piazzale Aldo Moro 5, I-00185 Rome, Italy, Email: daniele.barducci@roma1.infn.it; |
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| Publisher |
Springer |
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English |
Summary Language |
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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:000629645800001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4766 |
| Permanent link to this record |
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| Author |
Escribano, P.; Vicente, A. |
| Title |
Ultralight scalars in leptonic observables |
Type |
Journal Article |
| Year |
2021 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
03 |
Issue |
3 |
Pages |
240 - 37pp |
| Keywords |
Beyond Standard Model; CP violation; Neutrino Physics |
| Abstract |
Many new physics scenarios contain ultralight scalars, states which are either exactly massless or much lighter than any other massive particle in the model. Axions and majorons constitute well-motivated examples of this type of particle. In this work, we explore the phenomenology of these states in low-energy leptonic observables. After adopting a model independent approach that includes both scalar and pseudoscalar interactions, we briefly discuss the current limits on the diagonal couplings to charged leptons and consider processes in which the ultralight scalar phi is directly produced, such as μ-> e phi, or acts as a mediator, as in tau -> μμmu. Contributions to the charged leptons magnetic and electric moments are studied as well. |
| Address |
[Escribano, Pablo; Vicente, Avelino] Univ Valencia, CSIC, Inst Fis Corpuscular, C Catedrat Jose Beltran 2, E-46980 Valencia, Spain, Email: pablo.escribano@ific.uv.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 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:000635264700005 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
4769 |
| Permanent link to this record |
