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Author |
Abbas, G.; Celis, A.; Li, X.Q.; Lu, J.; Pich, A. |
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Title |
Flavour-changing top decays in the aligned two-Higgs-doublet model |
Type |
Journal Article |
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Year |
2015 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume  |
06 |
Issue |
6 |
Pages |
005 - 26pp |
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Keywords |
Rare Decays; Beyond Standard Model; Heavy Quark Physics |
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Abstract |
We perform a complete one-loop computation of the two-body flavour-changing top decays t --> ch and t --> cV (V = gamma, Z), within the aligned two-Higgs-doublet model. We evaluate the impact of the model parameters on the associated branching ratios, taking into account constraints from flavour data and measurements of the Higgs properties. Assuming that the 125 GeV Higgs corresponds to the lightest CP-even scalar of the CP-conserving aligned two-Higgs-doublet model, we find that the rates for such flavour-changing top decays lie below the expected sensitivity of the future high-luminosity phase of the LHC. Measurements of the Higgs signal strength in the di-photon channel are found to play an important role in limiting the size of the t --> ch decay rate when the charged scalar of the model is light. |
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Address |
[Abbas, Gauhar; Pich, Antonio] Univ Valencia, CSIC, IFIC, E-46071 Valencia, Spain, Email: Gauhar.Abbas@ific.uv.es; |
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Springer |
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English |
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ISSN |
1029-8479 |
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Conference |
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Notes |
WOS:000355745800001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2255 |
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Author |
Helo, J.C.; Hirsch, M.; Ota, T. |
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Title |
Long-range contributions to double beta decay revisited |
Type |
Journal Article |
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Year |
2016 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
06 |
Issue |
6 |
Pages |
006 - 32pp |
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Keywords |
Beyond Standard Model; Neutrino Physics |
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Abstract |
We discuss the systematic decomposition of all dimension-7 (d = 7) lepton number violating operators. These d = 7 operators produce momentum enhanced contributions to the long-range part of the 0 nu beta beta decay amplitude and thus are severely constrained by existing half-live limits. In our list of possible models one can find contributions to the long-range amplitude discussed previously in the literature, such as the left-right symmetric model or scalar leptoquarks, as well as some new models not considered before. The d = 7 operators generate Majorana neutrino mass terms either at tree-level, 1-loop or 2-loop level. We systematically compare constraints derived from the mass mechanism to those derived from the long-range 0 nu beta beta decay amplitude and classify our list of models accordingly. We also study one particular example decomposition, which produces neutrino masses at 2-loop level, can fit oscillation data and yields a large contribution to the long-range 0 nu beta beta decay amplitude, in some detail. |
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Address |
[Helo, J. C.] Univ Tecn Federico Santa Maria, Ctr Cient Tecnol Valparaiso, Casilla 110-5, Valparaiso, Chile, Email: juancarlos.helo@usm.cl; |
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Publisher |
Springer |
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English |
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Abbreviated Series Title |
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Series Volume |
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ISSN |
1029-8479 |
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Conference |
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Notes |
WOS:000377413400001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2721 |
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Author |
Gariazzo, S.; Giunti, C.; Laveder, M.; Li, Y.F. |
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Title |
Updated global 3+1 analysis of short-baseline neutrino oscillations |
Type |
Journal Article |
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Year |
2017 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
06 |
Issue |
6 |
Pages |
135 - 38pp |
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Keywords |
Neutrino Physics; Beyond Standard Model |
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Abstract |
We present the results of an updated fit of short-baseline neutrino oscillation data in the framework of 3+1 active-sterile neutrino mixing. We first consider v(e) and (v) over bar (e) disappearance in the light of the Gallium and reactor anomalies. We discuss the implications of the recent measurement of the reactor (v) over bar (e) spectrum in the NEOS experiment, which shifts the allowed regions of the parameter space towards smaller values of |U-e1|(2). The beta-decay constraints of the Mainz and Troitsk experiments allow us to limit the oscillation length between about 2 cm and 7 m at 3 sigma for neutrinos with an energy of 1 MeV. The corresponding oscillations can be discovered in a model-independent way in ongoing reactor and source experiments by measuring v(e) and (v) over bar (e), disappearance as a function of distance. We then consider the global fit of the data on short-baseline v(mu)((-)) -> v(e)((-)) transitions in the light of the LSND anomaly, taking into account the constraints from v(e)(( )) and v(mu)((-)) disappearance experiments, including the recent data of the MINOS and IceCube experiments. The combination of the NEOS constraints on |U-e4|(2) and the MINOS and IceCube constraints on |U-mu 4|(2) lead to an unacceptable appearance-disappearance tension which becomes tolerable only in a pragmatic fit which neglects the MiniBooNE low-energy anomaly. The minimization of the global chi(2) in the space of the four mixing parameters Delta m(41)(2), |U-e4|(2), |U-mu 4|(2) and |U-4 tau|(2) leads to three allowed regions with narrow Delta m(41)(2) widths at Delta m(41)(2) approximate to 1.7 (best-fit), 1.3 (at 2 sigma), 2.4 (at 3 sigma) eV(2). The effective amplitude of short-baseline v(mu)((-)) -> v(e)((-)) oscillations is limited by 0.00048 less than or similar to sin(2) 2 nu(e mu) less than or similar to 0.0020 at 3 sigma The restrictions of the allowed regions of the mixing parameters with respect to our previous global fits are mainly due to the NEOS constraints. We present a comparison of the allowed regions of the mixing parameters with the sensitivities of ongoing experiments, which show that it is likely that these experiments will determine in a definitive way if the reactor, Gallium and LSND anomalies are due to active-sterile neutrino oscillations or not. |
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Address |
[Gariazzo, S.] Univ Valencia, CSIC, Inst Fis Corpusc, Valencia, Spain, Email: gariazzo@ific.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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ISSN |
1029-8479 |
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Conference |
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Notes |
WOS:000404627200001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3190 |
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Author |
Caputo, A.; Hernandez, P.; Lopez-Pavon, J.; Salvado, J. |
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Title |
The seesaw portal in testable models of neutrino masses |
Type |
Journal Article |
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Year |
2017 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
06 |
Issue |
6 |
Pages |
112 - 20pp |
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Keywords |
Beyond Standard Model; Neutrino Physics |
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Abstract |
A Standard Model extension with two Majorana neutrinos can explain the measured neutrino masses and mixings, and also account for the matter-antimatter asymmetry in a region of parameter space that could be testable in future experiments. The testability of the model relies to some extent on its minimality. In this paper we address the possibility that the model might be extended by extra generic new physics which we parametrize in terms of a low-energy effective theory. We consider the effects of the operators of the lowest dimensionality, d = 5, and evaluate the upper bounds on the coefficients so that the predictions of the minimal model are robust. One of the operators gives a new production mechanism for the heavy neutrinos at LHC via higgs decays. The higgs can decay to a pair of such neutrinos that, being long-lived, leave a powerful signal of two displaced vertices. We estimate the LHC reach to this process. |
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Address |
[Caputo, A.; Hernandez, P.; Salvado, J.] Univ Valencia, Inst Fis Corpusc, Catedrat Jose Beltran 2, Valencia 46980, Spain, Email: andrea.caputo@cern.ch; |
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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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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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Series Issue |
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ISSN |
1029-8479 |
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Conference |
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Notes |
WOS:000404625300005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3196 |
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Author |
Helo, J.C.; Hirsch, M.; Ota, T. |
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Title |
Proton decay and light sterile neutrinos |
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 |
06 |
Issue |
6 |
Pages |
047 - 15pp |
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Keywords |
Beyond Standard Model; Neutrino Physics |
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Abstract |
Within the standard model, non-renormalizable operators at dimension six (d = 6) violate baryon and lepton number by one unit and thus lead to proton decay. Here, we point out that the proton decay mode with a charged pion and missing energy can be a characteristic signature of d = 6 operators containing a light sterile neutrino, if it is not accompanied by the standard pi(0)e(+) final state. We discuss this effect first at the level of effective operators and then provide a concrete model with new physics at the TeV scale, in which the lightness of the active neutrinos and the stability of the proton are related. |
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Address |
[Helo, Juan C.] Univ La Serena, Fac Ciencias, Dept Fis, Ave Cisternas 1200, La Serena, Chile, Email: jchelo@userena.cl; |
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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 |
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:000435023100004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3610 |
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