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Author |
Anamiati, G.; Castillo-Felisola, O.; Fonseca, R.M.; Helo, J.C.; Hirsch, M. |
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Title |
High-dimensional neutrino masses |
Type |
Journal Article |
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Year |
2018 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
12 |
Issue |
12 |
Pages |
066 - 26pp |
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Keywords |
Beyond Standard Model; Neutrino Physics |
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Abstract |
For Majorana neutrino masses the lowest dimensional operator possible is the Weinberg operator at d = 5. Here we discuss the possibility that neutrino masses originate from higher dimensional operators. Specifically, we consider all tree-level decompositions of the d = 9, d = 11 and d = 13 neutrino mass operators. With renormalizable interactions only, we find 18 topologies and 66 diagrams for d = 9, and 92 topologies plus 504 diagrams at the d = 11 level. At d = 13 there are already 576 topologies and 4199 diagrams. However, among all these there are only very few genuine neutrino mass models: At d = (9, 11, 13) we find only (2,2,2) genuine diagrams and a total of (2,2,6) models. Here, a model is considered genuine at level d if it automatically forbids lower order neutrino masses without the use of additional symmetries. We also briefly discuss how neutrino masses and angles can be easily fitted in these high-dimensional models. |
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Address |
[Anamiati, Gaetana; Hirsch, M.] Univ Valencia, CSIC, Inst Fis Corpuscular, AHEP Grp, Edificio Inst Paterna,Apartado 22085, E-46071 Valencia, Spain, Email: anamiati@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:000453296100001 |
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no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3845 |
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Author |
ATLAS Collaboration (Aaboud, M. et al); Alvarez Piqueras, D.; Aparisi Pozo, J.A.; Bailey, A.J.; Barranco Navarro, L.; Cabrera Urban, S.; Castillo, F.L.; Castillo Gimenez, V.; Cerda Alberich, L.; Costa, M.J.; Escobar, C.; Estrada Pastor, O.; Ferrer, A.; Fiorini, L.; Fullana Torregrosa, E.; Fuster, J.; Garcia, C.; Garcia Navarro, J.E.; Gonzalez de la Hoz, S.; Higon-Rodriguez, E.; Jimenez Pena, J.; Lacasta, C.; Lozano Bahilo, J.J.; Madaffari, D.; Mamuzic, J.; Marti-Garcia, S.; Melini, D.; Miñano, M.; Mitsou, V.A.; Rodriguez Bosca, S.; Rodriguez Rodriguez, D.; Ruiz-Martinez, A.; Salt, J.; Santra, A.; Soldevila, U.; Sanchez, J.; Valero, A.; Valls Ferrer, J.A.; Vos, M. |
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Title |
Search for the Higgs boson produced in association with a vector boson and decaying into two spin-zero particles in the H -> aa -> 4b channel in pp collisions at root s=13 TeV with the ATLAS detector |
Type |
Journal Article |
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Year |
2018 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
10 |
Issue |
10 |
Pages |
031 - 48pp |
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Keywords |
Beyond Standard Model; Hadron-Hadron scattering (experiments); Higgs physics |
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Abstract |
A search for exotic decays of the Higgs boson into a pair of spin-zero particles, H -> aa, where the a-boson decays into b-quarks promptly or with a mean proper lifetime c tau(a) up to 6 mm and has a mass in the range of 20-60GeV, is presented. The search is performed in events where the Higgs boson is produced in association with a W or Z boson, giving rise to a signature of one or two charged leptons (electrons or muons) and multiple jets from b-quark decays. The analysis is based on the dataset of proton-proton collisions at root s = 13TeV recorded in 2015 and 2016 by the ATLAS detector at the CERN Large Hadron Collider, corresponding to an integrated luminosity of 36: 1 fb(-1). No significant excess of events above the Standard Model background prediction is observed, and 95% confidence-level upper limits are derived for the production cross-sections for pp -> WH, ZH and their combination, times the branching ratio of the decay chain H -> aa -> 4b. For a-bosons which decay promptly, the upper limit on the combination of cross-sections for WH and ZH times the branching ratio of H -> aa -> 4b ranges from 3.0 pb for m(a) = 20 GeV to 1.3 pb for m(a) = 60 GeV, assuming that the ratio of WH to ZH cros-ssections follows the Standard Model prediction. For a-bosons with longer proper lifetimes, the most stringent limits are 1.8 pb and 0.68 pb, respectively, at c tau(a) similar to 0.4 mm. |
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Address |
[Duvnjak, D.; Jackson, P.; Oliver, J. L.; Petridis, A.; Qureshi, A.; Ruttinger, E. M.; Sharma, A. S.; White, M. J.] Univ Adelaide, Dept Phys, Adelaide, SA, Australia, Email: atlas.publications@cern.ch |
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Springer |
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English |
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1029-8479 |
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Expedition |
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Conference |
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Notes |
WOS:000447257400001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3790 |
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Permanent link to this record |
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Author |
Bordes, J.; Chan, H.M.; Tsun, S.S. |
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Title |
A closer study of the framed standard model yielding testable new physics plus a hidden sector with dark matter candidates |
Type |
Journal Article |
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Year |
2018 |
Publication |
International Journal of Modern Physics A |
Abbreviated Journal |
Int. J. Mod. Phys. A |
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Volume |
33 |
Issue |
33 |
Pages |
1850195 - 75pp |
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Keywords |
Gauge field theories; beyond the standard model; composite models; mass and mixing of fermions; dark matter |
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Abstract |
This closer study of the FSM (1) retains the earlier results of Ref. 1 in offering explanation for the existence of three fermion generations, as well as the hierarchical mass and mixing patterns of leptons and quarks; (II) predicts a vector boson G with mass of order TeV which mixes gamma with and Z of the standard model. The subsequent deviations from the standard mixing scheme are calculable in terms of the G mass. While these deviations for (i) mz – mw, (ii) Gamma(Z -> l (+)l( -)), and (iii) F(Z -> hadrons) are all within present experimental errors so long as mG > 1 TeV, they should soon be detectable if the G mass is not too much bigger; (III) suggests that in parallel to the standard sector familiar to us, there is another where the roles of flavour and colour are interchanged. Though quite as copiously populated and as vibrant in self-interactions as our own, it communicates but little with the standard sector except via mixing through a couple of known portals, one of which is the gamma – Z – G complex noted in (II), and the other is a scalar complex which includes the standard model Higgs. As a result, the new sectors paper. appears hidden to us as we appear hidden to them, and so its lowest members with masses of order 10 MeV, being electrically neutral and seemingly stable, but abundant, may make eligible candidates as constituents of dark matter. A more detailed summary of these results together with some remarks on the model's special theoretical features can be found in the last section of this paper. |
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Address |
[Bordes, Jose] Univ Valencia, CSIC, Ctr Mixto, Dept Fis Teor, Calle Dr Moliner 50, E-46100 Burjassot, Valencia, Spain, Email: bordes@uv.es; |
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World Scientific Publ Co Pte Ltd |
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English |
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Series Volume |
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ISSN |
0217-751x |
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Conference |
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Notes |
WOS:000453027500004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3844 |
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Permanent link to this record |
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Author |
Bordes, J.; Hong-Mo, C.; Tsun, T.S. |
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Title |
The Z boson in the framed standard model |
Type |
Journal Article |
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Year |
2018 |
Publication |
International Journal of Modern Physics A |
Abbreviated Journal |
Int. J. Mod. Phys. A |
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Volume |
33 |
Issue |
32 |
Pages |
1850190 - 19pp |
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Keywords |
Beyond the Standard Model; Z mixing; mass and decay of the electroweak gauge bosons; LHC phenomenology |
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Abstract |
The framed standard model (FSM), constructed initially for explaining the existence of three fermion generations and the hierarchical mass and mixing patterns of quarks and leptons,(1,2) suggests also a “hidden sector” of particles(3) including some dark matter candidates. It predicts in addition a new vector boson G, with mass of order TeV, which mixes with the gamma and Z of the standard model yielding deviations from the standard mixing scheme, all calculable in terms of a single unknown parameter mG. Given that standard mixing has been tested already to great accuracy by experiment, this could lead to contradictions, but it is shown here that for the three crucial and testable cases so far studied (i) m(Z) – m(W), (ii) Gamma(Z -> l(+)l(-)), (iii) Gamma(Z -> hadrons), the deviations are all within the present stringent experimental bounds provided m(G) > 1 TeV, but should soon be detectable if experimental accuracy improves. This comes about because of some subtle cancellations, which might have a deeper reason that is not yet understood. By virtue of mixing, G can be produced at the LHC and appear as a l(+)l(-) anomaly. If found, it will be of interest not only for its own sake but serve also as a window on to the “hidden sector” into which it will mostly decay, with dark matter candidates as most likely products. |
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Address |
[Bordes, Jose] Univ Valencia, Ctr Mixto CSIC, Dept Fis Teor, Calle Dr Moliner 50, E-46100 Burjassot, Valencia, Spain, Email: bordes@uv.es; |
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Corporate Author |
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Publisher |
World Scientific Publ Co Pte 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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Abbreviated Series Title |
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Series Volume |
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ISSN |
0217-751x |
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Conference |
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Notes |
WOS:000451433900008 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3821 |
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Permanent link to this record |
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Author |
Cepedello, R.; Fonseca, R.M.; Hirsch, M. |
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Title |
Systematic classification of three-loop realizations of the Weinberg operator |
Type |
Journal Article |
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Year |
2018 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
10 |
Issue |
10 |
Pages |
197 - 34pp |
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Keywords |
Beyond Standard Model; Neutrino Physics |
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Abstract |
We study systematically the decomposition of the Weinberg operator at three-loop order. There are more than four thousand connected topologies. However, the vast majority of these are infinite corrections to lower order neutrino mass diagrams and only a very small percentage yields models for which the three-loop diagrams are the leading order contribution to the neutrino mass matrix. We identify 73 topologies that can lead to genuine three-loop models with fermions and scalars, i.e. models for which lower order diagrams are automatically absent without the need to invoke additional symmetries. The 73 genuine topologies can be divided into two sub-classes: normal genuine ones (44 cases) and special genuine topologies (29 cases). The latter are a special class of topologies, which can lead to genuine diagrams only for very specific choices of fields. The genuine topologies generate 374 diagrams in the weak basis, which can be reduced to only 30 distinct diagrams in the mass eigenstate basis. We also discuss how all the mass eigenstate diagrams can be described in terms of only five master integrals. We present some concrete models and for two of them we give numerical estimates for the typical size of neutrino masses they generate. Our results can be readily applied to construct other d = 5 neutrino mass models with three loops. |
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Address |
[Cepedello, Ricardo; Hirsch, Martin] Univ Valencia, CSIC, AHEP Grp, Inst Fis Corpuscular, Edificio Inst Paterna,Apartado 22085, E-46071 Valencia, Spain, Email: ricepe@ific.uv.es; |
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Corporate Author |
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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 |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000449260800013 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3792 |
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Permanent link to this record |