Radiative neutrino mass generation through vectorlike quarks

Babu, K. S.; Julio, J.

doi:10.1103/physrevd.85.073005

Cited by 25 publications

(23 citation statements)

References 72 publications

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“…Such R-parity violating SUSY models have not only PTBM diagrams, but also RB type 2-loop diagrams [62]. Then there are leptoquark models [63] and extensions of the SM with vector-like quarks [64], with scalar and SM W boson diagrams. In this case, both CLBZ and PTBM in various variants contribute to the neutrino mass.…”

Section: Jhep03(2015)040mentioning

confidence: 99%

Systematic classification of two-loop realizations of the Weinberg operator

Sierra

Degée

Dorame

et al. 2015

J. High Energ. Phys.

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We systematically analyze the d = 5 Weinberg operator at 2-loop order. Using a diagrammatic approach, we identify two different interesting categories of neutrino mass models: (i) Genuine 2-loop models for which both, tree-level and 1-loop contributions, are guaranteed to be absent. And (ii) finite 2-loop diagrams, which correspond to the 1-loop generation of some particular vertex appearing in a given 1-loop neutrino mass model, thus being effectively 2-loop. From the large list of all possible 2-loop diagrams, the vast majority are infinite corrections to lower order neutrino mass models and only a moderately small number of diagrams fall into these two interesting classes. Moreover, all diagrams in class (i) are just variations of three basic diagrams, with examples discussed in the literature before. Similarly, we also show that class (ii) diagrams consists of only variations of these three plus two more basic diagrams. Finally, we show how our results can be consistently and readily used in order to construct two-loop neutrino mass models.

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Section: Jhep03(2015)040mentioning

confidence: 99%

Systematic classification of two-loop realizations of the Weinberg operator

Sierra

Degée

Dorame

et al. 2015

J. High Energ. Phys.

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“…Among the F ij couplings F 33 is allowed to be large by the LQ searches since it leads to the not yet ruled-out tτ decay channel. Therefore we further assume the other F ij couplings are small and satisfy the constraints [49,50,74,75]. Further, if F 33 is the largest F ij coupling, χ to be the dominant χ 1 decay channel.…”

Section: Light Leptoquarksmentioning

confidence: 99%

“…As a mater of fact there are many models with various motivations including models of GUT remnants [32][33][34][35][36][37][38][39], composite models [40][41][42][43][44][45][46][47][48] or a radiative neutrino mass models [49][50][51] which may give such contributions. Among these the scalars are interesting as they may play crucial role in the spontaneous symmetry breaking through additional terms with large portal couplings in the scalar potential.…”

Section: Introductionmentioning

confidence: 99%

Light Leptoquarks and Higgs Pair Production

2016

Proc. Mong. Acad. Sci.

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The data collected by the LHC experiments at 7 and 8 TeV with ~5 and 20fb-1 respectively is refining the details of the Higgs like resonances found last year [1,2]. Many decay channels have been searched for and the individual channels so far have given us a consistent picture with what one expects from the SM Higgs. On the other hand, the self interaction of the Higgs, which is probed by the Higgs pair production [3-7], is too feeble in the SM to be detected with these early data set. Even at 14 TeV run, the luminosity required for probing this process is very high [7-17]. This fact, namely the smallness of the corresponding Higgs pair production cross-section, makes it sensitive to a presence of a new physics [18-31]. In particular, relatively light colored particles are known to affect the cross-section substantially [18-22]. As a mater of fact there are many models with various motivations including models of GUT remnants [32-39], composite models [40-48] or a radiative neutrino mass models [49-51] which may give such contributions. Among these the scalars are interesting as they may play crucial role in the spontaneous symmetry breaking through additional terms with large portal couplings in the scalar potential. In the present work we study the phenomenological consequences of the Standard Model extension by two or more colored scalar particles. As a case study we take several leptoquarks (LQ) since there is an active experimental program by both ATLAS and CMS [52-57] and the lower bounds on their masses have now reached impressive levels some as high as a TeV value. On the other hand simultaneous presence of several LQs, may open up additional channels and therefore weakens these bounds. Specific models where the LQs are introduced to explain a certain phenomenon usually requires more than one LQs as in the model we study here. I examine a possibility of the existence of LQs with masses as light as ~180 GeV and study their effect for the single and di Higgs productions. As we will see the Higgs pair production is substantially altered in the low mass range below 300 GeV without too much change in the Higss diphoton decay channel if portal couplings are large. These couplings are required to have opposite signs by the latest Higgs data or small in magnitude. The model I consider has two LQs, an SU(2) doublet ω and a singlet χ. As we will see their simultaneous presence still allows them to have relatively light masses and escape the current bounds. In particular, the current bounds do not include LQs decaying to τt the masses below 200 GeV. Such a scenario, for example, has appeared in a model considered by Babu and Julio [49], where the light neutrino masses are induced by two-loop effects from LQs. If their masses are only of order few hundred GeV, as it is required in this case, the scenario can be probed or even excluded with the data from the LHC. Therefore this is one of the easiest model which can be tested and is the subject of the current study. Although I consider a particular model, it should be stressed that other models with colored particles can affect the pair productions in a similar manner.In Section II, I briefly list the current experimental status on the Higgs production and decay rates. Then I introduce the model I examined in the paper. Section III contains main part of this work where the numerical results for the single and pair Higgs productions are presented. The conclusion is given in Section IV.

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“…Therefore, new interactions must be added to the SM in order to allow for 0νβ β . We illustrate the different 2 Operators involving leptons and quarks with no gauge bosons generate neutrino masses at 1 to 4 loops [25,26,15,27] and may receive enhancements from top Yukawa couplings. possibilities diagrammatically in Figure 4, where only one LNV vertex is considered at a time.…”

Section: Np Contributions To 0νβ βmentioning

confidence: 99%

“…Proceedings of the Corfu Summer Institute 2012 "School and Workshops on Elementary Particle Physics and Gravity" September [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]2012 Corfu, Greece…”

mentioning

confidence: 99%

Neutrinoless double b decay with small neutrino masses

Águila¹,

Aparici²,

Bhattacharya³

et al. 2013

Proceedings of Proceedings of the Corfu Summer Institute 2012 — PoS(Corfu2012)

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If the only contribution to neutrinoless double beta decay (0νβ β ) are neutrino masses its discovery may be very difficult, especially if neutrinos present a normal hierarchy spectrum. However, this is not the only possibility; 0νβ β can in general produce electrons of either chirality, in contrast with the neutrino induced 0νβ β which predicts two left-handed electrons. Using an effective Lagrangian approach we classify the lepton number violating (LNV) effective operators with two leptons of either chirality but no quarks, ordered according to the magnitude of their contribution to 0νβ β . We point out that, for each of the three chirality assignments, e L e L , e L e R and e R e R , there is only one LNV operator of the corresponding type to lowest order, and these have dimensions 5, 7 and 9, respectively. Neutrino masses are always induced by these extra operators but can be delayed to one (dimension 7) or two loops (dimension 9). Under the assumption that 0νβ β is dominated by the operators of dimension 7 or 9 we find that the scale of new physics should be relatively low ( 30 TeV). We also list the SM additions generating these operators upon integration of the heavy modes, and discuss simple realistic examples of renormalizable theories for each case. The phenomenology of a model giving rise to the dimension 9 operator has been analyzed with some detail: if 0νβ β is going to be seen in the next round of experiments, the doubly charged scalars of the model could be seen at the LHC and lepton flavour violating (LFV) rates could be at the reach of foreseen experiments. Moreover neutrino masses, which arise at two loops, display a very particular structure and are strongly constrained, in fact, sin 2 θ 13 0.008, when µ → eee is required to lie below its present experimental limit.

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Radiative neutrino mass generation through vectorlike quarks

Cited by 25 publications

References 72 publications

Systematic classification of two-loop realizations of the Weinberg operator

Systematic classification of two-loop realizations of the Weinberg operator

Light Leptoquarks and Higgs Pair Production

Neutrinoless double b decay with small neutrino masses

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