Related papers: Multi-scale Renormalisation Group Improvement of t…
For supersymmetric extensions of the Standard Model we construct some expressions that include Yukawa couplings for the third and second generations and receive relatively small quantum corrections. This implies that they slightly depend on…
We derive and solve flow equations for a general O(N)-symmetric effective potential including wavefunction renormalization corrections combined with a heat-kernel regularization. We investigate the model at finite temperature and study the…
The three-dimensional Abelian Chern-Simons theory coupled to a scalar and a fermionic field of arbitrary charge is considered in order to study conformal symmetry breakdown and the effective potential stability. We present an improved…
We study the effects of renormalisation group running of the Wilson coefficients in Standard Model Effective Field Theory, using the process $pp \to t \bar{t}h$ as a showcase. We consider both strong and top Yukawa running effects, since…
We argue that the linear sigma model at small external momenta is an effective theory for the leading logarithms of chiral perturbation theory. Based on this assumption an attempt is made to sum these leading logarithms using the standard…
I outline why the renormalisation group is needed to analyse the scale dependence and hence determine the power counting for effective theories of strongly interacting systems. I summarise the results of several such analyses for two- and…
We study the Yukawa model with one scalar and one axial scalar fields, coupled to $N$ copies of Dirac fermions, in curved spacetime background. The theory possesses a reach set of coupling constants, including the scalar terms with odd…
Exact Renormalization Group techniques are applied to supersymmetric models in order to get some insights into the low energy effective actions of such theories. Starting from the ultra-violet finite mass deformed N=4 supersymmetric…
We consider logarithmic contributions to the free energy, instanton effective action and Laplace sum rules in QCD that are a consequence of radiative corrections. Upon summing these contributions by using the renormalization group, all…
The flow equations of the Functional Renormalization Group are applied to the O(N)-symmetric scalar theory, for N=1 and N=4, in four Euclidean dimensions, d=4, to determine the effective potential and the renormalization function of the…
We consider the electroweak radiative corrections in the MSSM and study the purely Yukawa contributions ${\cal O}(\alpha^L y_t^{2p} y_b^{2q})$, $p+q=L$, where $y_{t,b}$ are the top and bottom quark Yukawa couplings. We show that these…
Using renormalization-group methods, we derive differential equations for the all-orders summation of logarithmic corrections to the QCD series for R(s) = sigma(e^+ e^- --> hadrons)/sigma(e^+ e^- --> mu^+ mu^-), as obtained from the…
It has been demonstrated that the effective potential V(\phi) in a massless O(N) \lambda \phi^4_4 model is determined completely by the renormalization group functions provided the renormalization condition \frac{d^4V}{d…
We obtain the renormalization group(RG) functions for the $O(N)$ scalar field theory and the Higgs-Yukawa field theory with the Coleman-Weinberg mechanism in which the symmetry breaking occurs radiatively by using the method proposed…
Using the hierarchy of scales between the mass, $M$, and the width, $\Gamma$, of a heavy, unstable particle we construct an effective theory that allows calculations for resonant processes to be systematically expanded in powers of the…
Leptoquarks are theoretically well-motivated and have received increasing attention in recent years as they can explain several hints for physics beyond the Standard Model. In this article, we calculate the renormalisation group evolution…
We present a novel way to compute the one-loop ring-improved effective potential numerically, which avoids the spurious appearence of complex expressions and at the same time is free from the renormalization ambiguities of the…
Effective quantum field theories that allow for the possibility of Lorentz symmetry violation can sometimes also include redundancies of description in their Lagrangians. Explicit calculations in a Lorentz-violating generalization of Yukawa…
The renormalization group (RG) is used to study the asymptotically free $\phi_6^3$-theory in curved spacetime. Several forms of the RG equations for the effective potential are formulated. By solving these equations we obtain the one-loop…
We study the distorted wave renormalisation group (DWRG), a tool for constructing power-counting schemes in systems where some diagrams must be summed to all orders. We solve the DWRG eqaution for a variety of long-range potentials…