| Records |
| Author |
Aparici, A.; Herrero-Garcia, J.; Rius, N.; Santamaria, A. |
| Title |
Neutrino masses from new generations |
Type |
Journal Article |
| Year |
2011 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
07 |
Issue |
7 |
Pages |
122 |
| Keywords |
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| Abstract |
We reconsider the possibility that Majorana masses for the three known neutrinos are generated radiatively by the presence of a fourth generation and one right-handed neutrino with Yukawa couplings and a Majorana mass term. We find that the observed light neutrino mass hierarchy is not compatible with low energy universality bounds in this minimal scenario, but all present data can be accommodated with five generations and two right-handed neutrinos. Within this framework, we explore the parameter space regions which are currently allowed and could lead to observable effects in neutrinoless double beta decay, mu-e conversion in nuclei and μ-> e gamma experiments. We also discuss the detection prospects at LHC. |
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| ISSN |
1126-6708 |
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| Notes |
WOS:000293741500058 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ elepoucu @ |
Serial |
759 |
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| Author |
Herrero-Garcia, J.; Patrick, R.; Scaffidi, A. |
| Title |
A semi-supervised approach to dark matter searches in direct detection data with machine learning |
Type |
Journal Article |
| Year |
2022 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
| Volume |
02 |
Issue |
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Pages |
039 - 19pp |
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| Abstract |
The dark matter sector remains completely unknown. It is therefore crucial to keep an open mind regarding its nature and possible interactions. Focusing on the case of Weakly Interacting Massive Particles, in this work we make this general philosophy more concrete by applying modern machine learning techniques to dark matter direct detection. We do this by encoding and decoding the graphical representation of background events in the XENONnT experiment with a convolutional variational autoencoder. We describe a methodology that utilizes the `anomaly score' derived from the reconstruction loss of the convolutional variational autoencoder as well as a pre-trained standard convolutional neural network, in a semi-supervised fashion. Indeed, we observe that optimum results are obtained only when both unsupervised and supervised anomaly scores are considered together. A data set that has a higher proportion of anomaly score is deemed anomalous and deserves further investigation. Contrary to classical analyses, in principle all information about the events is used, preventing unnecessary information loss. Lastly, we demonstrate the reach of learning-focused anomaly detection in this context by comparing results with classical inference, observing that, if tuned properly, these techniques have the potential to outperform likelihood-based methods. |
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Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5495 |
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| Author |
Aparici, A.; Herrero-Garcia, J.; Rius, N.; Santamaria, A. |
| Title |
On the nature of the fourth generation neutrino and its implications |
Type |
Journal Article |
| Year |
2012 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
07 |
Issue |
7 |
Pages |
030 - 31pp |
| Keywords |
Beyond Standard Model; Neutrino Physics |
| Abstract |
We consider the neutrino sector of a Standard Model with four generations. While the three light neutrinos can obtain their masses from a variety of mechanisms with or without new neutral fermions, fourth-generation neutrinos need at least one new relatively light right-handed neutrino. If lepton number is not conserved this neutrino must have a Majorana mass term whose size depends on the underlying mechanism for lepton number violation. Majorana masses for the fourth-generation neutrinos induce relative large two-loop contributions to the light neutrino masses which could be even larger than the cosmological bounds. This sets strong limits on the mass parameters and mixings of the fourth-generation neutrinos. |
| Address |
[Aparici, Alberto] Univ Valencia, CSIC, Dept Fis Teor, Valencia 46071, Spain, Email: alberto.aparici@uv.es; |
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Springer |
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English |
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1126-6708 |
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| Notes |
WOS:000307298400030 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
1157 |
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| Author |
Bas i Beneito, A.; Herrero-Garcia, J.; Vatsyayan, D. |
| Title |
Multi-component dark sectors: symmetries, asymmetries and conversions |
Type |
Journal Article |
| Year |
2022 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
10 |
Issue |
10 |
Pages |
075 - 31pp |
| Keywords |
Models for Dark Matter; Particle Nature of Dark Matter |
| Abstract |
We study the relic abundance of several stable particles from a generic dark sector, including the possible presence of dark asymmetries. After discussing the different possibilities for stabilising multi-component dark matter, we analyse the final relic abundance of the symmetric and asymmetric dark matter components, paying special attention to the role of the unavoidable conversions between dark matter states. We find an exponential dependence of the asymmetries of the heavier components on annihilations and conversions. We conclude that having similar symmetric and asymmetric components is a natural outcome in many scenarios of multi-component dark matter. This has novel phenomenological implications, which we briefly discuss. |
| Address |
[Bas I Beneito, Arnau] Univ Valencia, Dept Fis Teor, C Catedrat Jose Beltran 2, E-46980 Paterna, Spain, Email: arnau.bas@ific.uv.es; |
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Springer |
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English |
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1029-8479 |
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| Notes |
WOS:000866484800002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
5380 |
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| Author |
Beniwal, A.; Herrero-Garcia, J.; Leerdam, N.; White, M.; Williams, A.G. |
| Title |
The ScotoSinglet Model: a scalar singlet extension of the Scotogenic Model |
Type |
Journal Article |
| Year |
2021 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
06 |
Issue |
6 |
Pages |
136 - 34pp |
| Keywords |
Beyond Standard Model; Higgs Physics; Neutrino Physics |
| Abstract |
The Scotogenic Model is one of the most minimal models to account for both neutrino masses and dark matter (DM). In this model, neutrino masses are generated at the one-loop level, and in principle, both the lightest fermion singlet and the lightest neutral component of the scalar doublet can be viable DM candidates. However, the correct DM relic abundance can only be obtained in somewhat small regions of the parameter space, as there are strong constraints stemming from lepton flavour violation, neutrino masses, electroweak precision tests and direct detection. For the case of scalar DM, a sufficiently large lepton-number-violating coupling is required, whereas for fermionic DM, coannihilations are typically necessary. In this work, we study how the new scalar singlet modifies the phenomenology of the Scotogenic Model, particularly in the case of scalar DM. We find that the new singlet modifies both the phenomenology of neutrino masses and scalar DM, and opens up a large portion of the parameter space of the original model. |
| Address |
[Beniwal, Ankit] Catholic Univ Louvain, Ctr Cosmol Particle Phys & Phenomenol CP3, B-1348 Louvain La Neuve, Belgium, Email: ankit.beniwal@uclouvain.be; |
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Springer |
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English |
Summary Language |
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| ISSN |
1029-8479 |
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| Area |
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Conference |
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| Notes |
WOS:000668611300001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4881 |
| Permanent link to this record |
