Jean-Francois Mathiot

arXiv2013

Aspects of fine-tuning of the Higgs mass within finite field theories

We reanalyze the perturbative radiative corrections to the Higgs mass within the Standard Model in the light of the Taylor-Lagrange renormalization scheme. This scheme naturally leads to completely finite corrections, depending on an arbitrary scale. The formulation avoids very large individual corrections to the Higgs mass. This illustrates the fact that the so-called fine-tuning problem in the Standard Model is just an artifact of the regularization scheme. It should therefore not lead to any physical interpretation in terms of the energy scale at which new physics should show up, nor in terms of a new symmetry. We analyze the intrinsic physical scales relevant for the description of these radiative corrections.

hep-ph↗

arXiv2010

Field theory on the light-front

We present a general framework to study relativistic compound systems in a Hamiltonian formalism. This formalism is based on the explicitly covariant formulation of light-front dynamics, with a decomposition of the state vector in Fock components. In order to be able to make definite predictions order by order in the truncation of the Fock expansion, we use an appropriate Fock sector dependent renormalization scheme. Our covariant formulation enables us to have a strict control of any violation of rotational invariance due to the choice of a given orientation of the light-front plane. This is mandatory in order to define the necessary renormalization conditions, and hence to be able to calculate physical observables. We emphasize the role played by antiparticle degrees of freedom in order to control, order by order in the Fock expansion, the scale invariance of physical observables. This nonperturbative framework demands also to use an appropriate regularization scheme. We show why the recently proposed Taylor-Lagrange regularization scheme is a very adequate scheme since it can be implemented very naturally, and from a systematic point of view, in light-front dynamics. As a direct application of this general framework, we settle the basis for a new formulation of chiral effective field theory in the baryonic sector based on light-front dynamics and a Fock decomposition of the state vector.

hep-th↗