Singlet scalar resonances and the diphoton excess

Abstract

ATLAS and CMS recently released the first results of searches for diphoton resonances in 13 TeV data, revealing a modest excess at an invariant mass of approximately 750 GeV. We find that it is generically possible that a singlet scalar resonance is the origin of the excess while avoiding all other constraints. We highlight some of the implications of this model and how compatible it is with certain features of the experimental results. In particular, we find that the very large total width of the excess is difficult to explain with loop-level decays alone, pointing to other interesting bounds and signals if this feature of the data persists. Finally we comment on the robust Zγ signature that will always accompany the model we investigate.

Scattering light by light at 750 GeV at the LHC

“…[14][15][16][17][18][19][20][21][22][23][24][25], an analogous coupling to gluons would be generated which would dominate the photon coupling by about an order of magnitude, and photon fusion would be subdominant. Hence an unavoidable consequence of a photon-fusion induced resonance would be the presence of uncolored new particles [26].…”

Diphoton excess at 750 GeV in leptophobic U(1)′ model inspired by E 6 GUT

“…We note that there are other diboson channels, h Φ → ZZ, W W . The bounds from LHC8 for the W W production [151] and ZZ production [152] are 27) respectively. In our model, h Φ does not interact with W and Z bosons at the tree-level directly so that the decay channels are suppressed by loop diagrams or Z-Z H mixing, which must be small.…”

Minimal Coleman-Weinberg theory explains the diphoton excess

“…Another implication of the new heavy quarks is that since S-boson is a real scalar [17][18][19][20][21][22][23][24][25][26][27][28][29], below the mass of M χ there can appear an effective gauge-invariant SM operator SB µν B µν with B µ the hypercharge gauge boson (in contrast to the pseudoscalar case, which instead couples to µνρσ B µν B ρσ [30][31][32][33][34][35][36][37]). This naturally implies S → γγ, ZZ, Zγ branchings that are roughly related as 1 : 0.09 : 0.6.…”