On the LHC signatures of $$SU(5)\times U(1)'$$ F-theory motivated models

Abstract

We study low energy implications of F-theory GUT models based on SU(5) extended by a $$U(1)'$$ U ( 1 ) ′ symmetry which couples non-universally to the three families of quarks and leptons. This gauge group arises naturally from the maximal exceptional gauge symmetry of an elliptically fibred internal space, at a single point of enhancement, $$E_8\supset SU(5)\times SU(5)'\supset SU(5)\times U(1)^4.$$ E 8 ⊃ S U ( 5 ) × S U ( 5 ) ′ ⊃ S U ( 5 ) × U ( 1 ) 4 . Rank-one fermion mass textures and a tree-level top quark coupling are guaranteed by imposing a $$Z_2$$ Z 2 monodromy group which identifies two abelian factors of the above breaking sequence. The $$U(1)'$$ U ( 1 ) ′ factor of the gauge symmetry is an anomaly free linear combination of the three remaining abelian symmetries left over by $$Z_2$$ Z 2 . Several classes of models are obtained, distinguished with respect to the $$U(1)'$$ U ( 1 ) ′ charges of the representations, and possible extra zero modes coming in vector-like representations. The predictions of these models are investigated and are compared with the LHC results and other related experiments. Particular cases interpreting the B-meson anomalies observed in LHCb and BaBar experiments are also discussed.

Flavor and Lepton Universality Violation Phenomena in F-Theory Inspired GUTs

“…The Table shows the U(1) charges, the flux data and the SM content of each matter curve. Using the data displayed in the Table it is straightforward to write down analytical expressions for the MSSM anomaly cancellation conditions and gauge anomaly conditions for the extra U(1) factor, which have been analysed in detail in [18,17]. It turns out that the MSSM anomaly cancellation conditions coincide with the chirality condition (2.7) imposed by the fluxes.…”

“…Skipping further technical details, next we present only the properties of the general spectrum as shown in Table 1. For a complete analysis we refer to our work [18].…”

“…In this talk we discuss non-universal U(1) s in F-theory inspired models [17,18]. We perform a detailed classification of this kind of models that naturally appear in F-theory and we discuss their phenomenological implications at low energies with emphasis on flavor violation phenomena.…”

SU(5) × U(1)′ Models with a Vector-like Fermion Family

“…In a previous study [10] (see also [11]), we performed a systematic analysis of a class of semi-local F-theory models with SU(5) × U(1) gauge symmetry obtained from a covering E 8 gauge group through the chain E 8 ⊃ SU(5) × SU(5) ⊃ SU(5) × U(1) 4 ⊃ SU(5) × U(1) ,…”

“…Despite the rich structure and the variety of the non-universal U(1) factors, strong lower bounds coming from the K − K system [12] on the mass of the associated Z boson far outweigh any observable effects in B-meson anomalies and the non-universal contributions to Br(B → Kµ + µ − )/Br(B → Ke + e − ) are completely depleted. It was shown that in the so-derived effective F-theory models, only the existence of additional vector-like families could interpret the LHCb data [10].…”