Eur. Phys. J. C (2016) 76: 170
https://doi.org/10.1140/epjc/s10052-016-4026-8

Regular Article - Theoretical Physics

The 750 GeV di-photon LHC excess and extra s in heterotic-string derived models

¹ Department of Mathematical Sciences, University of Liverpool, Liverpool, L69 7ZL, UK
² Department of Physics, University of Ioannina, 45110, Ioannina, Greece

^* e-mail: alon.faraggi@liv.ac.uk

Received: 7 February 2016
Accepted: 14 March 2016
Published online: 26 March 2016

Abstract

The ATLAS and CMS collaborations recently recorded possible di-photon excess at 750 GeV and a less significant di-boson excess around 1.9 TeV. Such excesses may be produced in heterotic string derived models, where the di-photon excess may be connected with the Standard Model singlet scalar responsible for the symmetry breaking, whereas the di-boson excess arises from production of the extra vector boson. Additional vector-like states in the string model are instrumental to explain the relatively large width of the di-photon events and mandated by anomaly cancellation to be in the vicinity of the breaking scale. Wilson line breaking of the non-Abelian gauge symmetries in the string models naturally gives rise to dark matter candidates. Future collider experiments will discriminate between the high-scale heterotic-string models, which preserve the perturbative unification paradigm indicated by the Standard Model data, versus the low scale string models. We also discuss the possibility for the production of the diphoton events with high scale breaking.