| 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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| Publisher |
Springer |
Place of Publication |
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| Language |
English |
Summary Language |
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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 |
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| Author |
Reig, M. |
| Title |
On the high-scale instanton interference effect: axion models without domain wall problem |
Type |
Journal Article |
| Year |
2019 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
08 |
Issue |
8 |
Pages |
167 - 13pp |
| Keywords |
Cosmology of Theories beyond the SM; Beyond Standard Model; Gauge Symmetry |
| Abstract |
We show that a new chiral, confining interaction can be used to break Peccei-Quinn symmetry dynamically and solve the domain wall problem, simultaneously. The resulting theory is an invisible QCD axion model without domain walls. No dangerous heavy relics appear. |
| Address |
[Reig, Mario] Univ Valencia, AHEP Grp, Inst Fis Corpuscular, CSIC, Parc Cient Paterna,C Catedrat Jose Beltran 2, E-46980 Valencia, Spain, Email: mario.reig@ific.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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Series Title |
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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:000483916900002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
4137 |
| Permanent link to this record |
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| Author |
Reig, M. |
| Title |
The stochastic axiverse |
Type |
Journal Article |
| Year |
2021 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
09 |
Issue |
9 |
Pages |
207 - 40pp |
| Keywords |
Cosmology of Theories beyond the SM; Beyond Standard Model; Compactification and String Models |
| Abstract |
In addition to spectacular signatures such as black hole superradiance and the rotation of CMB polarization, the plenitude of axions appearing in the string axiverse may have potentially dangerous implications. An example is the cosmological overproduction of relic axions and moduli by the misalignment mechanism, more pronounced in regions where the signals mentioned above may be observable, that is for large axion decay constant. In this work, we study the minimal requirements to soften this problem and show that the fundamental requirement is a long period of low-scale inflation. However, in this case, if the inflationary Hubble scale is lower than around O(100) eV, no relic DM axion is produced in the early Universe. Cosmological production of some axions may be activated, via the misalignment mechanism, if their potential minimum changes between inflation and today. As a particular example, we study in detail how the maximal-misalignment mechanism dilutes the effect of dangerous axions and allows the production of axion DM in a controlled way. In this case, the potential of the axion that realises the mechanism shifts by a factor increment theta = pi between the inflationary epoch and today, and the axion starts to oscillate from the top of its potential. We also show that axions with masses m(a) similar to O(1 – 100) H-0 realising the maximal-misalignment mechanism generically behave as dark energy with a decay constant that can take values well below the Planck scale, avoiding problems associated to super-Planckian scales. Finally, we briefly study the basic phenomenological implications of the mechanism and comment on the compatibility of this type of maximally-misaligned quintessence with the swampland criteria. |
| Address |
[Reig, Mario] Univ Valencia, CSIC, Inst Fis Corpuscular, C Catedratico Jose Beltran 2, E-46980 Paterna, Valencia, Spain, Email: mario.reig@ifis.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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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:000702371800004 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
4977 |
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| Author |
Barenboim, G.; Rasero, J. |
| Title |
Structure formation during an early period of matter domination |
Type |
Journal Article |
| Year |
2014 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
04 |
Issue |
4 |
Pages |
138 - 17pp |
| Keywords |
Cosmology of Theories beyond the SM; Beyond Standard Model |
| Abstract |
In this work we show that modifying the thermal history of the Universe by including an early period of matter domination can lead to the formation of astronomical objects. However, the survival of these objects can only be possible if the dominating matter decays to a daughter particle which is not only almost degenerate with the parent particle but also has an open annihilation channel. This requirement translates in an upper bound for the coupling of such a channel and makes the early structure formation viable. |
| Address |
[Barenboim, Gabriela] Univ Valencia, CSIC, Dept Fis Teor, E-46100 Burjassot, Spain, Email: gabriela.barenboim@uv.es; |
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| Publisher |
Springer |
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English |
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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:000335452600003 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
1777 |
| Permanent link to this record |
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| Author |
Racker, J.; Rius, N. |
| Title |
Helicitogenesis: WIMPy baryogenesis with sterile neutrinos and other realizations |
Type |
Journal Article |
| Year |
2014 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
11 |
Issue |
11 |
Pages |
163 - 19pp |
| Keywords |
Cosmology of Theories beyond the SM; Beyond Standard Model |
| Abstract |
We propose a mechanism for baryogenesis from particle decays or annihilations that can work at the TeV scale. Some heavy particles annihilate or decay into a heavy sterile neutrino N (with M greater than or similar to 0.5 TeV) and a “light” one nu (with m << 100 GeV), generating an asymmetry among the two helicity degrees of freedom of nu. This asymmetry is partially transferred to Standard Model leptons via fast Yukawa interactions and reprocessed into a baryon asymmetry by the electroweak sphalerons. We illustrate this mechanism in a WIMPy baryogenesis model where the helicity asymmetry is generated in the annihilation of dark matter. This model connects the baryon asymmetry, dark matter, and neutrino masses. Moreover it also complements previous studies on general requirements for baryogenesis from dark matter annihilation. Finally we discuss other possible realizations of this helicitogenesis mechanism. |
| Address |
[Racker, J.; Rius, N.] Univ Valencia, Dept Fis Teor, Inst Fis Corpuscular IFIC, CSIC, Valencia 46071, Spain, Email: racker@ific.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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Series Title |
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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:000347909700009 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
2078 |
| Permanent link to this record |
