arXiv subjects

Yannick Fischer

Publications and source records attributed to Yannick Fischer.

3 recordsLinked to original sources

arXiv2026

The Higgs boson through the lens of electroweak precision data

The global electroweak fit tests the quantum structure of the Standard Model by confronting precision measurements with high-order theoretical predictions. This paper presents an updated Gfitter analysis using the latest experimental inputs, notably the new world average of the $W$-boson mass, and state-of-the-art theoretical calculations. The fit yields indirect determinations of precision observables, including the $W$ and Higgs-boson masses, the top-quark mass, and the effective leptonic weak mixing angle, confirming the remarkable internal consistency of the Standard Model. The analysis is further extended to the Higgs sector by combining ATLAS and CMS signal-strength measurements with electroweak precision data in the $\kappa$ framework. The resulting electroweak constraints on the Higgs couplings to vector bosons allow a determination of the total Higgs-boson width with a precision of about 10\% or better within a leading-logarithmic oblique interpretation, and provide bounds on invisible and undetected Higgs-boson branching fractions without using direct searches for invisible Higgs decays. The paper also presents bounds on Wilson coefficients in the Standard Model Effective Field Theory together with projections for the precision of the global electroweak fit achievable at the FCC-ee.

hep-ph↗

arXiv2012

Some inverse problems around the tokamak Tore Supra

We consider two inverse problems related to the tokamak \textsl{Tore Supra} through the study of the magnetostatic equation for the poloidal flux. The first one deals with the Cauchy issue of recovering in a two dimensional annular domain boundary magnetic values on the inner boundary, namely the limiter, from available overdetermined data on the outer boundary. Using tools from complex analysis and properties of genereralized Hardy spaces, we establish stability and existence properties. Secondly the inverse problem of recovering the shape of the plasma is addressed thank tools of shape optimization. Again results about existence and optimality are provided. They give rise to a fast algorithm of identification which is applied to several numerical simulations computing good results either for the classical harmonic case or for the data coming from \textsl{Tore Supra}.

math.AP↗

arXiv2011

Dirichlet/Neumann problems and Hardy classes for the planar conductivity equation

We study Hardy spaces $H^p_ν$ of the conjugate Beltrami equation $\bar{\partial} f=ν\bar{\partial f}$ over Dini-smooth finitely connected domains, for real contractive $ν\in W^{1,r}$ with $r>2$, in the range $r/(r-1)<p<\infty$. We develop a theory of conjugate functions and apply it to solve Dirichlet and Neumann problems for the conductivity equation $\nabla.(σ\nabla u)=0$ where $σ=(1-ν)/(1+ν)$. In particular situations, we also consider some density properties of traces of solutions together with boundary approximation issues.

math.FA↗