Searching for lepton flavor violating flavon decays at hadron colliders

The search for flavons with a mass of O(1) TeV at current and future colliders might probe low-scale flavor models. We are interested in the simplest model that invokes the Froggatt-Nielsen mechanism with an Abelian flavor symmetry, which includes a Higgs doublet and a Froggatt-Nielsen complex singlet. Assuming a CP conserving scalar potential, there are a CP-even HF and a CP-odd AF flavons with lepton flavor violating (LFV) couplings. The former can mix with the standard-model-like Higgs boson, thereby inducing tree-level LFV Higgs interactions that may be at the reach of the LHC. We study the constraints on the parameter space of the model from low-energy LFV processes, which are then used to evaluate the flavon decay widths and the gg→ϕ→τμ (ϕ=HF,AF) production cross section at hadron colliders. After imposing several kinematic cuts to reduce the standard model main background, we find that for mHF about 200–350 GeV, the decay HF→τμ might be at the reach of the LHC for a luminosity in the range 1–3 ab−1, however, a luminosity of the order of 10 ab−1 would be required to detect the AF→τμ decay. On the other hand, a future 100 TeV pp collider could probe masses as high as O(10) TeV if it reaches an integrated luminosity of at least 20 ab−1. Therefore, the 100 TeV Collider could work as a flavon factory.