Complementary bound on the W′ mass from Higgs boson to diphoton decays

Using the left-right symmetric model as an illustrative example, we suggest a simple and straightforward way of constraining the W′ mass directly from the decay of the Higgs boson to two photons. The proposed method is generic and applicable to a diverse range of models with a W′-boson that couples to the Standard Model-like Higgs boson. Our analysis exemplifies how the precision measurement of the Higgs to diphoton signal strength can have a pivotal role in probing the scale of new physics.