Related papers: One-loop fermionic corrections to the instanton tr…
We discuss the phase structure of a lattice Higgs-Yukawa system in the variational mean field approximation with contributions of fermionic determinant being calculated in a ladder approximation. In particular, we demonstrate that in this…
We calculate the $O(p^6)$ corrections to the anomalous form factors appearing in $\pi^+$, $K^+ \to e^+ \nu \gamma,\ \mu^+\nu\gamma$ and $K_{l4}$ decays in Chiral Perturbation Theory. The relevant dimension $6$ terms of the lagrangian are…
We classify all the phenomenologically viable fermion mass matrices coming from a spontaneously broken abelian symmetry $ U(1)_X, $ with one and two additional chiral fields of opposite charges $ X=\pm 1. $ We find that the non-trivial…
We study a chirally invariant Higgs-Yukawa model regulated on a space-time lattice. We calculate Higgs boson resonance parameters and mass bounds for various values of the mass of the degenerate fermion doublet. Also, first results on the…
We extend our previous results on the evolution of quantum fermi fields in Minkowski gauge field backgrounds to the case of spontaneously broken gauge theories. We obtain a selection rule which relates the amount of fermion number violation…
We compute the fermionic radiative contributions to the decay $H^+ \to W^{+(*)} A^0$ in the framework of models with two Higgs doublets (2HDM), for the case of an on-shell and off-shell W. We show that, in the majority of the cases, current…
We propose a novel way to break grand unified gauge symmetries via the Hosotani mechanism in models that can accommodate chiral fermions. Adjoint scalar fields are realized through the so-called diagonal embedding method which is often used…
We study the continuum limit of the $2D$ U(1)--Higgs model with variable scalar field length, which is qualitatively different from the fixed length case. Our simulations concentrate on the scaling behaviour of the topological…
We present the complete one-loop corrected Higgs mass within the Standard Model. It is crucial to identify the observable mass as the renormalized one that depends on the external momentum. The correction is finite and dominated by the…
The Higgs-mass dependence of the Standard Model contributions to the correlation between the gauge-boson masses is studied at the two-loop level. Exact results are given for the Higgs-dependent two-loop corrections associated with the…
Physical implications of a vector-like extension of the standard model for heavier quarks and leptons with $SU(2)\times U(1)$ gauge symmetry and only one Higgs doublet are discussed. This scheme incorporates infinitely many fermions, and…
We show that a version of the covariant gauge anomaly for a 3+1 dimensional chiral fermion interacting with a non-Abelian gauge field can be obtained from the classical Hamiltonian flow of its probability distribution in phase space. The…
We discuss instanton fermionic zero modes in the heterotic N=(0,2) modification of the CP(1) sigma model in two dimensions. By calculating its chiral anomaly we prove that the number of fermionic zero modes is same as in the standard…
Renormalizability of a lattice chiral fermion is studied at one loop level in the overlap formulation in four dimensions. The fermion chirality is examined including the self-energy corrections due to gauge interactions. Divergent terms…
We describe in some detail a computer evaluation of a 't Hooft vertex in a two dimensional model using the overlap. The computer result agrees with the known exact continuum value, and in this sense our work is a first successful fully…
We compute the two-loop corrections of O(alpha_s^2) to the Yukawa couplings in the framework of the Minimal Supersymmetric Standard Model (MSSM). The calculation is performed using the effective Lagrangian approach under the approximation…
Spontaneously broken Abelian gauge symmetries can explain the fermion mass hierarchies of the minimal supersymmetric standard model. In most cases it is assumed that the $U(1)_H$ symmetry is anomalous. However, non-anomalous models are also…
The type-I region of phase transitions at finite temperature of the U(1)-Higgs theory in 3+1 dimensions is investigated in detail using a Wilsonian renormalisation group. We consider in particular the quantitative effects induced through…
In the standard model, the Higgs boson $h$ couples to the quarks and charged leptons according to the well-known formula $(m_\psi/v) h \bar{\psi}\psi$, where $\psi$ = quark (q) or lepton (l) and $v$ = 246 GeV is its vacuum expectation…
We calculate radiative corrections to a full set of coupling constants for the 125 GeV Higgs boson at the one-loop level in two Higgs doublet models with four types of Yukawa interaction under the softly-broken discrete $Z_2$ symmetry. The…