Related papers: Pion to photon transition form factor: Beyond vale…
We present the first calculation of the pion electromagnetic form factor at physical light quark masses. This form factor parameterises the deviations from the behaviour of a point-like particle when a photon hits the pion. These deviations…
Quantum Field Theory (QFT) is used to describe the physics of particles in terms of their fundamental constituents. The Light-Front Field Theory~(LFFT), introduced by Paul Dirac in 1949, is an alternative approach to solve some of the…
In this paper, we calculate the matrix element and form factors of vector-to-vector ($V'\to V'$) transition within the standard light-front~(SLF) and covariant light-front~(CLF) quark models~(QMs), and investigate the self-consistency and…
For the flavor-singlet heavy quark system of charmonia in the pseudoscalar ($\eta_c(1S)$) channel, we calculate the elastic (EFF) and transition form factors (TFF) ($\eta_c(1S) \rightarrow \gamma \gamma^*$) for a wide range of photon…
We propose an effective field theory (EFT) of fractional quantum Hall systems near the filling fraction $\nu=5/2$ that flows to pertinent IR candidate phases, including non-abelian Pfaffian, anti-Pfaffian, and particle-hole Pfaffian states…
We study the electromagnetic structure of the pion in terms of the quantum cromodynamic~(QCD) model on the Breit-frame. We calculated the observables, such as the electromagnetic form factor. The priori to have a calculation covariant need…
We propose a novel method to experimentally access the gravitational form factors (GFFs) of the charged pion $\pi^+$ through the Sullivan process in electron-proton scattering. We demonstrate that the cross sections of…
We calculate the form factors of $B\to\pi$ and $B\to\rho$ heavy to light transition matrix elements by using the factorization formalism of perturbative QCD. We obtain them at $q^2=0$ and show their dependences on the parameter $\epsilon$…
We complement studies of the neutral pion transition form factor pi^0 --> gamma^(*) gamma^(*) with calculations for the electromagnetic decay widths of the processes pi^0 --> e^+ e^-, pi^0 --> e^+ e^- gamma and pi^0 --> e^+ e^- e^+ e^-.…
In this talk it is reported on an analysis of the form factors for the transitions from a photon to one of the pseudoscalar mesons pi0, eta, eta', etac within the modified perturbative approach in which quark transverse degrees of freedom…
We update the theoretical framework for the QCD calculation of transition form factors $\gamma^*\gamma\to\eta$ and $\gamma^*\gamma\to\eta'$ at large photon virtualities including full next-to-leading order analysis of perturbative…
We discuss the nonleading, ``soft" contribution to the pion form factor at intermediate momentum transfer within operator product expansion approach. We argue, that the corresponding contribution can temporarily {\bf simulate} the leading…
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…
We calculate next-to-leading-order (NLO) corrections to the $B\to\pi$ transition form factors at leading twist in the $k_T$ factorization theorem. Light partons off-shell by $k_T^2$ are considered in the quark diagrams, in the effective…
We present an investigation of the electromagnetic pion form factor, $F_\pi(Q^2)$, at small values of the four-momentum transfer $Q^2$ ($\lesssim 0.25$ GeV$^2$), based on the gauge configurations generated by European Twisted Mass…
We perform a perturbative QCD analysis of the gravitational form factors (GFFs) of nucleon at large momentum transfer. We derive the explicit factorization formula of the GFFs in terms of twist-3 and twist-4 light-cone distribution…
Nucleon and pion electromagnetic form factors are evaluated in the spacelike region within a light-front constituent quark model, where eigenfunctions of a mass operator, reproducing a large set of hadron energy levels, are adopted and…
We investigate the scattering of a quark on a heavy nucleus at high energies using the time-dependent basis light-front quantization (tBLFQ) formalism, which is the first application of the tBLFQ formalism in QCD. We present the real-time…
The pion electromagnetic form factor is calculated at lower and higher momentum transfer in order to explore constituent quark models and the differences among those models. In particular, the light-front constituent quark model is utilized…
We apply the light-cone technique to electroproduction reaction $ep\to e\pi^+n$ long considered as a means of measuring the electromagnetic form factor of the pion. We show that the interpretation of the long-standing puzzle of large…