Related papers: Analysis of strong coupling constant with machine …
In this work, we use the artificial neural network (ANN) method to study and predict the distribution of strong coupling constants by fitting the existing data. Our approach takes advantage of the ability of ANN to learn complex nonlinear…
We present recent developments on the role of the running coupling constant at the intersection of perturbative and nonperturbative QCD. A number of experiments show a smooth transition from small to large scales given by the four-momentum…
We present an analysis of the role of the running coupling constant at the intersection of perturbative and nonperturbative QCD. Although the approaches that have been considered so far in these two regimes appear to be complementary to…
We investigate the possibility that unification occurs at strong coupling. We show that, despite the fact the couplings pass through a strong coupling regime, accurate predictions for their low energy values are possible because the…
We extract an effective strong coupling constant using low-Q^2 data and sum rules. Its behavior is established over the full Q^2-range and is compared to calculations based on lattice QCD, Schwinger-Dyson equations and a quark model.…
The strong coupling constant is one of the fundamental parameters of the standard model of particle physics. In this review I will briefly summarise the theoretical framework, within which the strong coupling constant is defined and how it…
One of the main open questions in physics is the understanding of the internal structure of the strongly interacting particles, or hadrons. It is still a challenge to describe consistently the dynamics of scattering processes and hadronic…
We present a first attempt to experimentally extract an effective strong coupling constant that we define to be a low Q2 extension of a previous definition by S. Brodsky et al. following an initial work of G. Grunberg. Using Jefferson Lab…
We propose a novel method to determine the strong coupling of quantum chromodynamics (QCD) and fix its running behavior at all scales by using the Bjorken sum rules (BSR). The BSR defines an effective coupling $\alpha^{g_1}_s(Q)$ which…
We unify two widely different approaches to understanding the infrared behaviour of quantum chromodynamics (QCD), one essentially phenomenological, based on data, and the other computational, realised via quantum field equations in the…
We describe the coupling of the strong force. Denoted as $\alpha_s$, it sets the strength of that force, just as $G$ or $\alpha$ specify the strength of the gravity and electromagnetism. Its value depends on the scale at which phenomena are…
Recently, a number of intriguing results have been obtained for strongly coupled ${\cal N}=4$ Supersymmetric Yang-Mills theory in vacuum and matter, using the AdS/CFT correspondence. In this work, we provide a physical picture supporting…
A high precision determination of the strong coupling constant in the MS-bar scheme at the Z-mass scale, using low energy quantities, namely pion/kaon decay constants and masses, as experimental input is presented. The computation employs…
Following the successful prediction of an exact value for the fine structure constant later confirmed to differ numerically from the centre value of the latest experimental recommended CODATA range by 10^{-12}, further analysis and…
Theoretical predictions for particle production cross sections and decays at colliders rely heavily on perturbative Quantum Chromodynamics (QCD) calculations, expressed as an expansion in powers of the strong coupling constant $\alpha_s$.…
The prediction of the strong coupling constant in grand unified theories is reviewed, first in the standard model, then in the supersymmetric version. Various corrections are considered. The predictions in both supergravity-induced and…
The compatibility of theoretically calculated values for the strong coupling constant,through the renormalization group approach with experimental data is studied. There exist considerable divergence in-between theoretical and experimental…
Recently developed strong-coupling theory open up the possibility of treating quantum-mechanical systems with hard-wall potentials via perturbation theory. To test the power of this theory we study here the exactly solvable quantum…
Continuum strong QCD is the application of models and continuum quantum field theory to the study of phenomena in hadronic physics, which includes; e.g., the spectrum of QCD bound states and their interactions; and the transition to, and…
Strong and ultra-strong light-matter coupling are remarkable phenomena of quantum electrodynamics occurring when the interaction between a matter excitation and the electromagnetic field cannot be described by usual perturbation theory.…