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Author  |
Bjorkeroth, F.; de Medeiros Varzielas, I.; Lopez-Ibañez, M.L.; Melis, A.; Vives, O. |
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Title |
Leptogenesis in Delta(27) with a universal texture zero |
Type |
Journal Article |
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Year |
2019 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
09 |
Issue |
9 |
Pages |
050 - 24pp |
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Keywords |
Beyond Standard Model; GUT; Neutrino Physics |
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Abstract |
We investigate the possibility of viable leptogenesis in an appealing Delta(27) model with a universal texture zero in the (1,1) entry. The model accommodates the mass spectrum, mixing and CP phases for both quarks and leptons and allows for grand unification. Flavoured Boltzmann equations for the lepton asymmetries are solved numerically, taking into account both N-1 and N-2 right-handed neutrino decays. The N-1-dominated scenario is successful and the most natural option for the model, with M-1 is an element of [10(9), 10(12)] GeV, and M-1/M-2 is an element of [0.002, 0.1], which constrains the parameter space of the underlying model and yields lower bounds on the respective Yukawa couplings. Viable leptogenesis is also possible in the N-2-dominated scenario, with the asymmetry in the electron flavour protected from N-1 washout by the texture zero. However, this occurs in a region of parameter space which has a stronger mass hierarchy M-1/M-2< 0.002, and M-2 relatively close to M-3, which is not a natural expectation of the Delta(27) model. |
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Address |
[Bjorkeroth, Fredrik] INFN, Lab Nazl Frascati, CP 13, I-100044 Frascati, Italy, Email: fredrik.bjorkeroth@lnf.infn.it; |
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Springer |
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English |
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ISSN |
1029-8479 |
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Notes |
WOS:000485053000001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4139 |
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Author |
Calibbi, L.; Lopez-Ibañez, M.L.; Melis, A.; Vives, O. |
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Title |
Implications of the Muon g-2 result on the flavour structure of the lepton mass matrix |
Type |
Journal Article |
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Year |
2021 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
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Volume |
81 |
Issue |
10 |
Pages |
929 - 11pp |
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Keywords |
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Abstract |
The confirmation of the discrepancy with the Standard Model predictions in the anomalous magnetic moment by theMuon g-2 experiment at Fermilab points to a low scale of new physics. Flavour symmetries broken at low energies can account for this discrepancy but these models are much more restricted, as they would also generate offdiagonal entries in the dipole moment matrix. Therefore, if we assume that the observed discrepancy in the muon g – 2 is explained by the contributions of a low-energy flavor symmetry, lepton flavour violating processes can constrain the structure of the lepton mass matrices and therefore the flavour symmetries themselves predicting these structures. We apply these ideas to several discrete flavour symmetries popular in the leptonic sector, such as Delta(27), A(4), and A(5) proportional to CP. |
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Address |
[Calibbi, Lorenzo] Nankai Univ, Sch Phys, Tianjin 300071, Peoples R China, Email: calibbi@nankai.edu.cn; |
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Springer |
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English |
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ISSN |
1434-6044 |
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Notes |
WOS:000709829900003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5017 |
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Author |
Calibbi, L.; Lopez-Ibañez, M.L.; Melis, A.; Vives, O. |
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Title |
Muon and electron g – 2 and lepton masses in flavor models |
Type |
Journal Article |
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Year |
2020 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
06 |
Issue |
6 |
Pages |
087 - 23pp |
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Keywords |
Precision QED; Beyond Standard Model; Effective Field Theories; Quark Masses and SM Parameters |
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Abstract |
The stringent experimental bound on μ-> e gamma is compatible with a simultaneous and sizable new physics contribution to the electron and muon anomalous magnetic moments (g – 2)(l) (l = e, mu), only if we assume a non-trivial flavor structure of the dipole operator coefficients. We propose a mechanism in which the realization of the (g – 2)(l) correction is manifestly related to the mass generation through a flavor symmetry. A radiative flavon correction to the fermion mass gives a contribution to the anomalous magnetic moment. In this framework, we introduce a chiral enhancement from a non-trivial O(1) quartic coupling of the scalar potential. We show that the muon and electron anomalies can be simultaneously explained in a vast region of the parameter space with predicted vector-like mediators of masses as large as M chi is an element of [0.6, 2.5] TeV. |
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Address |
[Calibbi, Lorenzo] Nankai Univ, Sch Phys, Tianjin 300071, Peoples R China, Email: calibbi@nankai.edu.cn; |
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Springer |
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English |
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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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Area |
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Expedition |
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Conference |
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Notes |
WOS:000542705000001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4443 |
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Author |
de Medeiros Varzielas, I.; Lopez-Ibañez, M.L.; Melis, A.; Vives, O. |
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Title |
Controlled flavor violation in the MSSM from a unified Delta(27) flavor symmetry |
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 |
09 |
Issue |
9 |
Pages |
047 - 22pp |
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Keywords |
Beyond Standard Model; Supersymmetric Standard Model; Quark Masses and SM Parameters |
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Abstract |
We study the phenomenology of a unified supersymmetric theory with a flavor symmetry Delta(27). The model accommodates quark and lepton masses, mixing angles and CP phases. In this model, the Dirac and Majorana mass matrices have a unified texture zero structure in the (1, 1) entry that leads to the Gatto-Sartori-Tonin relation between the Cabibbo angle and ratios of the masses in the quark sectors, and to a natural departure from zero of the theta 13(l) angle in the lepton sector. We derive the flavor structures of the trilinears and soft mass matrices, and show their general non-universality. This causes large flavor violating effects. As a consequence, the parameter space for this model is constrained, allowing it to be (dis)proven by flavor violation searches in the next decade. Although the results are model specific, we compare them to previous studies to show similar flavor effects (and associated constraints) are expected in general in supersymmetric flavor models, and may be used to distinguish them. |
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Address |
[Varzielas, Ivo de Medeiros] Univ Lisbon, Inst Super Tecn, Dept Fis, CFTP, Ave Rovisco Pais 1, P-1049 Lisbon, Portugal, Email: ivo.de@udo.edu; |
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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:000444676300004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3735 |
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Author |
Gambino, P.; Melis, A.; Simula, S. |
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Title |
Extraction of heavy-quark-expansion parameters from unquenched lattice data on pseudoscalar and vector heavy-light meson masses |
Type |
Journal Article |
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Year |
2017 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
96 |
Issue |
1 |
Pages |
014511 - 17pp |
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Keywords |
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Abstract |
We present a precise lattice computation of pseudoscalar and vector heavy-light meson masses for heavy-quark masses ranging from the physical charm mass up to similar or equal to 4 times the physical b-quark mass. We employ the gauge configurations generated by the European Twisted Mass Collaboration (ETMC) with N-f = 2 + 1 + 1 dynamical quarks at three values of the lattice spacing (a similar or equal to 0.062; 0.082; 0.089 fm) with pion masses in the range M-pi similar or equal to 210-450 MeV. The heavy-quark mass is simulated directly on the lattice up to similar or equal to 3 times the physical charm mass. The interpolation to the physical b-quark mass is performed using the ETMC ratio method, based on ratios of the meson masses computed at nearby heavy-quark masses, and adopting the kinetic mass scheme. The extrapolation to the physical pion mass and to the continuum limit yields m(b)(kin) (1 GeV) = 4.61(20) GeV, which corresponds to (m) over bar (b) ((m) over bar (b)) 4.26(18) GeV in the (MS) over bar scheme. The lattice data are analyzed in terms of the heavy-quark expansion (HQE) and the matrix elements of dimension-four and dimension-five operators are extracted with a good precision, namely,(Lambda) over bar = 0.552(26) GeV, mu(2)(pi) = 0.321(32) GeV2, and mu(2)(G)(m(b)) = 0.253(25) GeV2. The data also allow for a rough estimate of the dimension-six operator matrix elements. As the HQE parameters play a crucial role in the inclusive determination of the Cabibbo-Kobayashi-Maskawa matrix elements V-ub and V-cb, their precise determination on the lattice may eventually validate and improve the analyses based on fits to the semileptonic moments. |
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Address |
[Gambino, P.] Univ Turin, Dipartimento Fis, Via P Giuria 1, I-10125 Turin, Italy |
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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 |
2470-0010 |
ISBN |
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Conference |
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Notes |
WOS:000406298500005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3224 |
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