Left-right asymmetry and 750 GeV diphoton excess

We propose left-right models based on $SU(3{)}_C\otimes SU(M{)}_L\otimes SU(N{)}_R\otimes U(1{)}_X$ gauge symmetry for $(M,N)=(3,3),(2,3)$, and (3,2) that address the 750 GeV diphoton excess recently reported by the LHC. The fermion contents are minimally introduced, and the generation number must match the fundamental color number in order to cancel anomalies and ensure QCD asymptotic freedom. The diphoton excess arises from the field that breaks the left-right symmetry spontaneously in the first model, while for the other models it emerges as an explicit violation of the left-right symmetry. The neutrino masses, flavor-changing neutral currents, and new boson searches are also discussed.

Figure 1

The cross section for $pp\to S\to \gamma \gamma$ at the LHC $\sqrt{s}=13\mathrm{TeV}$ and $m_S=750\mathrm{GeV}$.

Figure 2

The cross section for $pp\to X\to \gamma \gamma$ at the LHC $\sqrt{s}=13\mathrm{TeV}$ and $m_X=750\mathrm{GeV}$.

Figure 3

The cross section for $pp\to X\to \gamma \gamma$ at the LHC $\sqrt{s}=13\mathrm{TeV}$ and $m_X=750\mathrm{GeV}$.

Figure 4

The cross section for $pp\to S\to \gamma \gamma$ at the LHC $\sqrt{s}=13\mathrm{TeV}$ and $m_X=750\mathrm{GeV}$. The $w$ scale is taken as $w=3\mathrm{TeV}$.