Quantum-hydrodynamical picture of the massive Higgs boson

The phenomenon of spontaneous symmetry breaking admits a physical interpretation in terms of the Bose condensation process of elementary spinless quanta. In this picture, the broken-symmetry phase emerges as a real physical medium, endowed with a hierarchical pattern of scales, supporting two types of elementary excitations for k→0: a massive energy branch Ea(k)→MH, corresponding to the usual Higgs boson field, and a collective gapless branch Eb(k)→0. This is similar to the coexistence of phonons and rotons in superfluid 4He that, in fact, is usually considered the condensed-matter analog of the Higgs condensate. After previous work dedicated to the properties of the gapless phonon branch, in this paper we use quantum hydrodynamics to propose a physical interpretation of the massive branch. On the base of our results, MH coincides with the energy gap for vortex formation and a massive Higgs boson is like a roton in superfluid 4He. Within this interpretation of the Higgs particle, there is no naturalness problem since MH remains a naturally intermediate, fixed energy scale, even for an ultimate ultraviolet cutoff Λ→∞. (orig.)