Zobrazeno 1 - 10
of 540
pro vyhledávání: '"Stefanis, N."'
Autor:
Stefanis, N. G.
The data behavior of the pion-photon transition form factor (TFF) is discussed using a nonlinear mathematical model with two parameters $B$ and $C$. We show for the Belle data that the inherent inhibition of this model inevitably yields asymptoticall
Externí odkaz:
http://arxiv.org/abs/2412.03403
We study two versions of lightcone sum rules to calculate the $\gamma^*\gamma\rightarrow\pi^0$ transition form factor (TFF) within QCD. While the standard version is based on fixed-order perturbation theory by means of a power-series expansion in the
Externí odkaz:
http://arxiv.org/abs/2111.12469
Autor:
Mikhailov, S. V., Stefanis, N. G.
Publikováno v:
Phys. Rev. D 104, 096103 (2021)
We discuss cross-link relations between the $\pi$ and $\rho$-meson channels emerging from two different descriptions of the QCD vacuum: Instanton physics and QCD sum rules with nonlocal condensates (NLC). We derive in both schemes an intriguing linea
Externí odkaz:
http://arxiv.org/abs/2106.15522
Publikováno v:
Phys. Rev. D 103, 096003 (2021)
We show that using renormalization-group summation to generate the QCD radiative corrections to the $\pi-\gamma$ transition form factor, calculated with lightcone sum rules (LCSR), renders the strong coupling free of Landau singularities while preser
Externí odkaz:
http://arxiv.org/abs/2101.12661
Autor:
Stefanis, N. G.
Publikováno v:
Phys. Rev. D 102, 034022 (2020)
We study the pion-photon transition form factor (TFF) $F^{\gamma*\gamma\pi^0}(Q^2)$ using a state-of-the art implementation of light cone sum rules (LCSRs) within fixed-order QCD perturbation theory. The spectral density in the dispersion relation in
Externí odkaz:
http://arxiv.org/abs/2006.10576
Publikováno v:
EPJ Web Conf. 222 (2019) 03017
We consider the lightcone sum-rule (LCSR) description of the pion-photon transition form factor in combination with the renormalization group of QCD. The emerging scheme represents a certain version of Fractional Analytic Perturbation Theory and sign
Externí odkaz:
http://arxiv.org/abs/1911.02845
Autor:
Stefanis, N. G.
We discuss the evaluation of the transition form factor (TFF) $F^{\gamma*\gamma\pi^0}(Q^2)$ by means of QCD theory and by state-space reconstruction from topological data analysis. We first calculate this quantity in terms of quark-gluon interactions
Externí odkaz:
http://arxiv.org/abs/1904.02631
Publikováno v:
Phys. Rev. D 98, 096017 (2018); Erratum Phys. Rev. D 101, 059901(E)(2020)
We consider the lightcone sum-rule description of the pion-photon transition form factor, based on dispersion relations, in combination with the renormalization group of QCD, in terms of the formal solution of the Efremov-Radyushkin-Brodsky-Lepage ev
Externí odkaz:
http://arxiv.org/abs/1806.07790
Publikováno v:
EPJ Web of Conferences 137, 01003 (2017)
A survey is presented on the current status of 3D nucleon tomography. Several research frontiers are addressed that dominate modern physics from theory to current and future experiments. We have now a much more detailed spatial image of the nucleon t
Externí odkaz:
http://arxiv.org/abs/1612.03077
Publikováno v:
EPJ Web of Conferences 137, 05016 (2017)
We consider the pion-photon transition form factor at low to intermediate spacelike momenta within the theoretical framework of light-cone sum rules. We derive predictions which take into account all currently known contributions stemming from QCD pe
Externí odkaz:
http://arxiv.org/abs/1611.02086