Diphoton excess at 750 GeV: Singlet scalars confront triviality

Abstract

We suggest that the recently observed diphoton excess at 750 GeV comes from a quasi-degenerate bunch of gauge singlet scalars produced and decaying through one or more vector-like fermions. This explains the broad nature of the resonance, even though the decay is loop-mediated. At the same time, the model keeps the new Yukawa couplings in the perturbative region, which is necessary for the stability of the potential.

Comments: 7 pages, 4 figures, uses pdflatex. v2: Slight change in the title, the naturalness argument in the text as well as Fig. 1(b) removed, the rest remains unchanged. More references added. Version to be published in Phys. Rev. D