Related papers: Constraining the $g'_1$ coupling in the minimal $B…
We study constraints among coupling constants of the standard model obtained in the noncommutative geometry (NCG) method. First, we analyze the evolution of the Higgs boson mass under the renormalization group by adopting the idea of…
The field-theoretical renormalization group approach is used to estimate the universal critical value g_6^* of renormalized sextic coupling constant for the two-dimensional Ising model. Four-loop perturbative expansion for g_6 is calculated…
In this paper we develop perturbation theory on the reduced space of a principal $G-$bundle. This theory uses a multiscale method and is related to vibrodynamics. For a fast oscillating motion with the symmetry Lie group $G$, we prove that…
Despite much recent progress in model building with D-branes, it has been problematic to find a completely convincing explanation of gauge coupling unification. We extend the class of models by considering F-theory compactifications, which…
We reanalyze precision LEP data and coupling constant unification in the minimal supersymmetric $SU(5)$ model including the evolution of the gaugino masses. We derive general bounds on the primordial gaugino supersymmetry-breaking…
We study the renormalizable singlet-doublet fermionic extension of the Standard Model. In this model, the new vector-like fermions couple to the gauge bosons and to the Higgs via new Yukawa couplings, that allow for nontrivial mixing in the…
We revisit the question of gauge coupling unification at the string scale in orbifold compactifications of the heterotic string for the supersymmetric Standard Model. In the presence of discrete Wilson lines threshold corrections with…
We set up a numerical S-matrix bootstrap problem to rigorously constrain bound state couplings given by the residues of poles in elastic amplitudes. We extract upper bounds on these couplings that follow purely from unitarity, crossing…
We consider a class of minimal abelian extensions of the Standard Model with an extra neutral gauge boson $Z'$ at the TeV scale. In these scenarios an extended scalar sector and heavy right-handed neutrinos are naturally envisaged. We…
A distinctive feature of string unification is the possibility of unification by a non-simply-laced group. This occurs most naturally in four dimensional type~II string models where the gauge symmetry is realized by Kac-Moody algebras at…
We consider dominant 3-, 4-, and 5-loop contributions to $\lambda$, the quartic scalar coupling-constant's $\beta$-function in the Standard Model. We find that these terms accelerate the evolution of $\lambda$ to nonperturbative values,…
We study the generic features of minimal gauge extensions of the Standard Model in view of recent hints of lepton-flavor non-universality in semi-leptonic $b \to s \ell^+ \ell^-$ and $b \to c \ell \nu$ decays. We classify the possible…
The gauged $U(1)_{L_{\mu}-L_{\tau}}$ model can provide for additional contributions to the muon anomalous magnetic moment by means of a loop involving the $Z^{\prime}$ gauge boson. However, the parameter space of such models is severely…
We impose partial-wave unitarity on $2 \to 2$ tree-level scattering processes to derive constraints on the dimensions of large scalar and fermionic multiplets of arbitrary gauge groups. We apply our results to scalar and fermionic…
The scale invariant of the effective potential of the standard model at two-loop is used as a boundary condition under the assumption that the two-loop effective potential approximates the full effective potential. This condition leads with…
Motivated by a simultaneous explanation of the apparent discrepancies in the light charged lepton anomalous magnetic dipole moments, and the anomalous internal pair creation in $^8$Be nuclear transitions, we explore a simple New Physics…
In this talk I discuss extended Higgs sectors in which the 125 GeV Higgs boson couplings to W and Z bosons can be larger than in the Standard Model. Constraints from perturbative unitarity and the electroweak rho parameter limit the number…
We consider heterotic Calabi-Yau compactifications with S(U(4)xU(1)) background gauge fields. These models lead to gauge groups with an additional U(1) factor which, under certain conditions, can combine with hypercharge to a B-L symmetry.…
The difference between baryon number B and lepton number L is the only anomaly-free global symmetry of the Standard Model, easily promoted to a local symmetry by introducing three right-handed neutrinos, which automatically make neutrinos…
It is shown that the commonly accepted relationship between the Landau singularity in the running coupling constant of QED or QCD and the renormalon singularities in the Borel sums of perturbation theory expansions is only a particular…