Implications of Gauge Invariance on a Heavy Diphoton Resonance
Assuming a heavy electroweak singlet scalar, which couples to the Standard Model gauge bosons only through loop-induced couplings, SU(2)_L x U(1)_Y gauge invariance imposes interesting patterns on its decays into electroweak gauge bosons, which are dictated by only two free parameters. Therefore experimental measurements on any two of the four possible electroweak channels would determine the remaining two decay channels completely. Furthermore, searches in the WW/ZZ channels probe a complimentary region of parameter space from searches in the gamma-gamma/Z-gamma channels. We derive a model-independent upper bound on the branching fraction in each decay channel, which for the diphoton channel turns out to be about 61%. Including the coupling to gluons, the upper bound on the diphoton branching fraction implies an upper bound on the mass scale of additional colored particles mediating the gluon-fusion production. Using an event rate of about 5 fb for the reported 750 GeV diphoton excess, we find the new colored particle must be lighter than O(1.7 TeV) and O(2.6 TeV) for a pure CP-even and a pure CP-odd singlet scalar, respectively.
- Publication Date:
- OSTI Identifier:
- Report Number(s):
- FERMILAB-PUB-15-583-T; arXiv:1512.09089
- DOE Contract Number:
- Resource Type:
- Journal Article
- Resource Relation:
- Journal Name: Phys.Rev.Lett.
- Research Org:
- Argonne National Laboratory (ANL), Argonne, IL (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
- Sponsoring Org:
- USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
- Country of Publication:
- United States
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
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