Flavour-Changing Decays of a 125 GeV Higgs-like Particle

Understand

The ATLAS and CMS experiments at the LHC have reported the observation of a possible excess of events corresponding to a new particle $h$ with mass $\sim 125$ GeV that might be the long-sought Higgs boson, or something else.

• Decyphering the nature of this possible signal will require constraining the couplings of the $h$ and measuring them as accurately as possible.
• Here we analyze the indirect constraints on flavour-changing $h$ decays that are provided by limits on low-energy flavour-changing interactions.
• We find that indirect limits in the quark sector impose such strong constraints that flavour-changing $h$ decays to quark-antiquark pairs are unlikely to be observable at the LHC.