Systematic Study of Diphoton Resonance at 750 GeV from Sgoldstino

The ATLAS and CMS Collaborations of the Large Hadron Collider (LHC) have reported an excess of events in diphoton channel with invariant mass of about 750 GeV. With low energy supersymmetry breaking, we systematically consider the sgoldstino scalar $S$ as the new resonance, which is a linear combination of the CP-even scalar $s$ and CP-odd pseudoscalar $a$. Because we show that $s$ and $a$ can be degenerated or have large mass splitting, we consider two cases for all the following three scenarios: (1) Single resonance. $s$ is the 750 GeV resonance decays to a pair of 1 GeV pseudoscalar $a$. With suitable decay length, these two $a$ decay into collimated pair of photons which cannot be distinguished at the LHC and may appear as diphotons instead of four photons. (2) Twin resonances. $m_{s}\approx m_{a}$ with a mass difference of about 40 GeV and both $s$ and $a$ decay into diphoton pairs. For productions, we consider three scenarios: (I) vector boson fusion; (II) gluon gluon fusion; (III) $q{\bar q}$ pair production. In all these scenarios with two kinds of resonances, we find the parameter space that satisfies the diphoton production cross section from 3 to 13 ${\rm fb}$ and all the other experimental constraints. And we address the decay width as well. In particular, in the third scenario, we observe that the production cross section is small but the decay width of $s$ or $a$ can be from 40 to 60 GeV.

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