Searching for Nambu-Goldstone Bosons at the LHC

Understand

Phenomenological implications of a minimal extension to the Standard Model are considered, in which a Nambu-Goldstone boson emerges from the spontaneous breaking of a global U(1) symmetry.

• This is felt only by a scalar field which is a singlet under all Standard Model symmetries, and possibly by neutrinos.
• Mixing between the Standard Model Higgs boson field and the new singlet field may lead to predominantly invisible Higgs boson decays.
• The "natural" region in the Higgs boson mass spectrum is determined, where this minimally extended Standard Model is a valid theory up to a high scale related with the smallness of neutrino masses.