Recently, both ATLAS and CMS Collaborations report an excess at 750 GeV in the diphoton invariant mass spectrum at 13 TeV LHC. If it is a new (pseudo)scalar produced via a loop-induced gluon-gluon fusion process, it is important to know what the particle in the loop is. In this work, we investigate the possibility of determining the fraction of the contribution from the standard-model top quark in the loop.

• Received 23 February 2016

DOI:https://doi.org/10.1103/PhysRevD.93.114032