| Records |
| Author |
Aristizabal Sierra, D.; Staub, F.; Vicente, A. |
| Title |
Shedding light on the b -> s anomalies with a dark sector |
Type |
Journal Article |
Year  |
2015 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
92 |
Issue |
1 |
Pages |
015001 - 11pp |
| Keywords |
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| Abstract |
The LHCb Collaboration has recently reported on some anomalies in b -> s transitions. In addition to discrepancies with the Standard Model (SM) predictions in some angular observables and branching ratios, an intriguing hint for lepton universality violation was found. Here we propose a simple model that extends the SM with a dark sector charged under an additional U(1) gauge symmetry. The spontaneous breaking of this symmetry gives rise to a massive Z' boson, which communicates the SM particles with a valid dark matter candidate, while solving the b -> s anomalies with contributions to the relevant observables. |
| Address |
[Sierra, D. Aristizabal; Vicente, Avelino] Univ Liege, Dept Astrophys Geophys & Oceanog, IFPA, B-4000 Liege 1, Belgium, Email: daristizabal@ulg.ac.be; |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Physical Soc |
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 |
1550-7998 |
ISBN |
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Medium |
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| Area |
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Expedition |
|
Conference |
|
| Notes |
WOS:000357492700006 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
2297 |
| Permanent link to this record |
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| Author |
Aristizabal Sierra, D.; Tortola, M.; Valle, J.W.F.; Vicente, A. |
| Title |
Leptogenesis with a dynamical seesaw scale |
Type |
Journal Article |
| Year |
2014 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
| Volume |
07 |
Issue |
7 |
Pages |
052 - 20pp |
| Keywords |
leptogenesis; baryon asymmetry; particle physics – cosmology connection; neutrino theory |
| Abstract |
In the simplest type-I seesaw leptogenesis scenario right-handed neutrino annihilation processes are absent. However, in the presence of new interactions these processes are possible and can affect the resulting B – L asymmetry in an important way. A prominent example is provided by models with spontaneous lepton number violation, where the existence of new dynamical degrees of freedom can play a crucial role. In this context, we provide a model-independent discussion of the effects of right-handed neutrino annihilations. We show that in the weak washout regime, as long as the scattering processes remain slow compared with the Hubble expansion rate throughout the relevant temperature range, the efficiency can be largely enhanced, reaching in some cases maximal values. Moreover, the B – L asymmetry yield turns out to be independent upon initial conditions, in contrast to the “standard” case. On the other hand, when the annihilation processes are fast, the right-handed neutrino distribution tends to a thermal one down to low temperatures, implying a drastic suppression of the efficiency which in some cases can render the B – L generation mechanism inoperative. |
| Address |
[Sierra, D. Aristizabal; Vicente, A.] Univ Liege, IFPA, Dept Astrophys Geophys & Oceanog, B-4000 Liege, Belgium, Email: daristizabal@ulg.ac.be; |
| Corporate Author |
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Thesis |
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| Publisher |
Iop Publishing Ltd |
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 |
1475-7516 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
|
| Notes |
WOS:000339802700053 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1868 |
| Permanent link to this record |
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| Author |
Aristizabal Sierra, D.; Bazzocchi, F.; de Medeiros Varzielas, I.; Merlo, L.; Morisi, S. |
| Title |
Tri/Bi-maximal lepton mixing and leptogenesis |
Type |
Journal Article |
| Year |
2010 |
Publication |
Nuclear Physics B |
Abbreviated Journal |
Nucl. Phys. B |
| Volume |
827 |
Issue |
1-2 |
Pages |
34-58 |
| Keywords |
|
| Abstract |
In models with flavour symmetries added to the gauge group of the Standard Model the CP-violating asymmetry necessary for leptogenesis may be related with low-energy parameters. A particular case of interest is when the flavour symmetry produces exact Tri/Bi-maximal lepton mixing leading to a vanishing CP-violating asymmetry. In this paper we present a model-independent discussion that confirms this always occurs for unflavoured leptogenesis in type I see-saw scenarios, noting however that Tri/Bi-maximal mixing does not imply a vanishing asymmetry in general scenarios where there is interplay between type I and other see-saws. We also consider a specific model where the exact Tri/Bi-maximal mixing is lifted by corrections that can be parametrised by a small number of degrees of freedom and analyse in detail the existing link between low and high-energy parameters – focusing on how the deviations from Tri/Bi-maximal are connected to the parameters governing leptogenesis. |
| Address |
[Merlo, L.] Univ Padua, Dipartimento Fis G Galilei, Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy, Email: daristi@lnf.infn.it |
| Corporate Author |
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Thesis |
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| Publisher |
Elsevier Science Bv |
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 |
0550-3213 |
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 |
ISI:000272669900002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ elepoucu @ |
Serial |
512 |
| Permanent link to this record |
