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- Phenomenology of a flavored multiscalar Branco-Grimus-Lavoura-like model with three generations of massive neutrinosPublication . Ferreira, Pedro Miguel; Freitas, Felipe F.; Pino Gonçalves, João; Morais, António P.; Pasechnik, Roman; Vatellis, VasileiosIn this paper, we present several possible anomaly free implementations of the Branco-Grimus-Lavoura (BGL) model with two Higgs doublets and one singlet scalar. The model also includes three generations of massive neutrinos that get their mass via a type-I seesaw mechanism. A particular anomaly free realization, which we dub νBGL-1 scenario, is subjected to an extensive phenomenological analysis, from the perspective of flavor physics and collider phenomenology.
- Anomalies in B-meson decays and the muon g-2 from dark loopsPublication . Huang, Da; Morais, António P.; Santos, RuiWe explore a class of models which can provide a common origin for the recently observed evidence for lepton flavor universality violation in b -> sl(+)l(-) decays, the dark matter (DM) problem, and the long-standing muon (g - 2) anomaly. In particular, both anomalies in the B meson decays and the muon (g - 2) can be explained by the additional one-loop diagrams with DM candidates. We first classify several simple models according to the new fields' quantum numbers. We then focus on a specific promising model and perform a detailed study of both DM and flavor physics. A random scan over the relevant parameter space reveals that there is indeed a large parameter space which can explain the three new physics phenomena simultaneously, while satisfying all other flavor and DM constraints. Finally, we discuss some of the possible new physics signatures at the Large Hadron Collider.
- CP violating hW(+)W(-) coupling in the Standard Model and beyondPublication . Huang, Da; Morais, António P.; Santos, RuiInspired by the recent development in determining the property of the observed Higgs boson, we explore the CP-violating (CPV) -cCPVhW+mu nu Wmu nu-/upsilon coupling in the Standard Model (SM) and beyond, where W-+/- mu nu and W+/- mu nu denote the W-boson field strength and its dual. To begin with, we show that the leading-order SM contribution to this CPV vertex appears at two-loop level. By summing over the quark flavor indices in the two loop integrals analytically, we can estimate the order of the corresponding Wilson coefficient to be cCPVSMsimilar to O10-23, which is obviously too small to be probed at the LHC and planned future colliders. Then we investigate this CPV hW(+)W(-) interaction in two Beyond the Standard Model benchmark models: the left-right model and the complex 2-Higgs doublet model (C2HDM). Unlike what happens for the SM, the dominant contributions in both models arise at the one-loop level, and the corresponding Wilson coefficient can be as large as of O(10(-9)) in the former model and of O(10(-3)) for the latter. In light of such a large CPV effect in the hW(+)W(-) coupling, we also give the formulae for the leading one-loop contribution to the related CPV hZZ effective operator in the complex 2-Higgs doublet model. The order of magnitude of the Wilson coefficients in the C2HDM may be within reach of the high-luminosity LHC or planned future colliders.
- Collider phenomenology of new neutral scalars in a flavored multi-higgs modelPublication . Ferreira, Pedro; Gonçalves, João; de Aguiar e Pestana de Morais, António; Onofre, Antonio; Pasechnik, Roman; Vatellis, VasileiosIn this work, we propose and explore for the first time a new collider signature of heavy neutral scalars typically found in many distinct classes of multi-Higgs models. This signature, particularly relevant in the context of the Large Hadron Collider (LHC) measurements, is based on a topology with two charged leptons and four jets arising from first and second generation quarks. As an important benchmark scenario of the multi-Higgs models, we focus on a recently proposed Branco-Grimus-Lavoura (BGL) type model enhanced with an Abelian U(1) flavor symmetry and featuring an additional sector of right-handed neutrinos. We discuss how kinematics of the scalar fields in this model can be used to efficiently separate the signal from the dominant backgrounds and explore the discovery potential of the new heavy scalars in the forthcoming LHC runs. The proposed method can be applied for analysis of the statistical significance of heavy scalars' production at the LHC and future colliders in any multi-Higgs model.