DecaysZ′→γγγandZ→γγγin the minimal 331 model

Abstract

The possibility of a significant effect of exotic particles on the Z ′ → γγγ and Z → γγγ decays is investigated in the context of the minimal 331 model. This model, which is based in the SUC (3) × SUL(3) × UX (1) gauge group, predicts the existence of many exotic charged particles that can significantly enhance the decay widths. It is found that the standard model prediction for the Z → γγγ decay remains essentially unchanged, as the new physics effects quickly decouples. On the other hand, it is found that the contributions of the new exotic quarks and gauge bosons predicted by this model lead to a branching fraction for the Z ′ → γγγ decay of about 10 −6 , which is about 3 orders of magnitude larger than that of the Z → γγγ decay.

Limits on the quartic couplingsZγγγandZZγγfrome+Gutiérrez‐Rodríguez1, Honorato2, Montaño3 et al. 2014Phys. Rev. DSelf Cite281180View full textAdd to dashboardCite

“…In particular, we present the connection among our quartic couplings G 1,2 and the results obtained in Ref. [5] for the branching ratio of the decay mode Z → γγγ in the SM and the 331 model.…”

“…(1) and (2), we include the connection of the G 1,2 couplings to the results obtained for the Z → γγγ decay in Ref. [5]. These form factors are dominated by the fermionic virtual contributions and they are essentially the same in both the SM and the 331 model, but unfortunately with rather low values, 1.63 × 10 −10 and 1.33 × 10 −10 , respectively.…”

“…All the couplings G 1,2 and a 0,c are CP conserving and within the SM all of them vanish at tree level. As far as we know, the a 0,c have not been computed explicitly in the SM, whereas the couplings G 1,2 can be extracted directly from the recent calculation performed in the SM and the 331 model [16] for the branching ratio of the rare decay mode Z → γγγ [5].…”

“…However, it has been found recently in a detailed calculation of the one-loop induced decay mode Z → γγγ, in both the SM and the 331 model, that the respective scalar contributions are suppressed with respect to the dominant virtual fermionic contributions [5]. This is also the case in the one-loop contributions to TNGC [3,6].…”

“…Since there is not a published account, as far as we know, of the calculation of the Zγγγ vertices in the SM, we present a brief analysis on the connection of the Zγγγ form factors to the analytical results obtained in Ref. [5] for the branching ratio of the decay mode Zγγγ in both the SM and the 331 model. However, a similar calculation for the ZZγγ form factors in the SM is not available in the published literature.…”