The flavor-locked flavorful two Higgs doublet model

Abstract

We propose a new framework to generate the Standard Model (SM) quark flavor hierarchies in the context of two Higgs doublet models (2HDM). The 'flavorful' 2HDM couples the SM-like Higgs doublet exclusively to the third quark generation, while the first two generations couple exclusively to an additional source of electroweak symmetry breaking, potentially generating striking collider signatures. We synthesize the flavorful 2HDM with the 'flavor-locking' mechanism, that dynamically generates large quark mass hierarchies through a flavor-blind portal to distinct flavon and hierarchon sectors: Dynamical alignment of the flavons allows a unique hierarchon to control the respective quark masses. We further develop the theoretical construction of this mechanism, and show that in the context of a flavorful 2HDM-type setup, it can automatically achieve realistic flavor structures: The CKM matrix is automatically hierarchical with |V cb | and |V ub | generically of the observed size. Exotic contributions to meson oscillation observables may also be generated, that may accommodate current data mildly better than the SM itself.

Higgs bosons with large couplings to light quarks

“…• Flavorful 2HDMs [136][137][138][139][140][141][142]: there are also models in the literature where the SM-like…”

Probing flavor nonuniversal theories through Higgs physics at the LHC and future colliders

“…However, we can consider models where the operator under considerations applies to the first two generations universally, maintaining a U (2) 2 -flavor symmetry in the quark sector (benchmark theory 2). These types of models can be motivated due to the large mass gap between the second and third generation [23,24]. In this scenario, g ij = diag (1, 1, 0).…”

“…Note that the current studies and analyses of the Higgs physics at current and future colliders focus more on the universal theories, especially where electroweak precision observables (EWPO) enter. However, in general, BSM theories, such as supersymmetry, composite * wenhan@uchicago.edu † zliuphys@umd.edu ‡ liantaow@uchicago.edu Higgs, as well as quark flavor models, the third generation and the first two generations can be considerably different [15][16][17][18][19][20][21][22][23][24]. The constraints from LEP measurements on such new physics scenarios are rather weak.…”

Rare top decays as probes of flavorful Higgs bosons

“…The observed pattern of quark masses and mixing can be obtained by asserting suitable textures for the quark mass matrices, leading to a "flavorful" Two Higgs Doublet Model (F2HDM). The Yukawa structure of the F2HDM can be for example generated via the flavor-locking mechanism [23,24], and the implied collider phenomenology has been discussed in detail in [25]. Variations of the original F2HDM with alternative flavor structures were explored in [26] (for additional recent work on extended Higgs sectors with non-standard flavor structures see [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]).…”

“…Because the mass hierarchies in the up quark sector are rather different than those in the down quark sector, the flavor-locking mechanism [23,24] is not suitable for generating the CKM matrix in the up sector. Thus, we will consider a scenario where the required up Yukawa textures are dynamically generated by a Froggatt-Nielsen (FN) type mechanism [42].…”