Related papers: Interpolating Axial Anomaly Induced Amplitudes
A consistent treatment of $B\rightarrow \pi l \nu$ decay is given on the light-front. The $B$ to $\pi$ transition form factors are calculated in the entire physical range of momentum transfer for the first time. The valence-quark…
We study an abstract model of an oscillator realized by an amplifier embedded in a positive feedback loop. The power and frequency stability of the output of such an oscillator are limited by quantum noise added by two elements in the loop:…
The transition pion-photon form factor is studied within the framework of Light-Cone QCD Sum Rules. The spectral density for the next-to-leading order corrections is calculated for any Gegenbauer harmonic. At the level of the…
A cosmic axion, via the electromagnetic anomaly, induces an oscillating electric dipole for the electron of frequency $m_a$ and strength $\sim$(few)$\times 10^{-32}$ e-cm, two orders of magnitude above the nucleon, and within a few orders…
We express the leading electromagnetic corrections in K-> pi pi amplitudes as integrals over the virtual photon squared-momentum Q^2. The high Q^2 behavior is obtained via the operator product expansion. The low Q^2 behavior is calculated…
We discuss the axial form factors of the nucleon within the context of the nonrelativistic chiral quark model. Partial conservation of the axial current (PCAC) imposed at the quark operator level enforces an axial coupling for the…
Bounds on the expansion coefficients of the strangeness changing $K\pi$ form factors were derived recently from analyticity and unitarity, using as input suitable correlation functions calculated by perturbative QCD in the Euclidian region.…
The transition form factor of a gamma into three pions $F_{3\pi}$ are studied in a framework of nonlocal chiral quark model. In local limit the result is agreement with chiral perturbative theory and reproduce Wess-Zumino-Witten anomaly.…
A general mechanism is presented by which topological physics arises in strongly correlated systems without flat bands. Starting from a charge transfer insulator, topology emerges when the charge transfer energy between the cation and anion…
The $\gamma^\ast N \to N(1520)$ transition has a property that differs from the other low-lying nucleon resonance amplitudes: the magnitude of the transverse helicity amplitudes.The transition helicity amplitudes are defined in terms of…
We report on the fully analytic calculation of the leading-power contribution to the photon-pion transition form factor $\gamma \, \gamma^{\ast} \to \pi^0$ at two loops in QCD. The applied techniques are based on hard-collinear…
We revisit the evaluations for the spacelike and timelike $\rho \pi$ transition form factors $F_{\rho\pi}(Q^2)$ and $G_{\rho\pi}(Q^2)$ with the inclusion of the the next-to-leading order (NLO) QCD contributions in the framework of the $k_T$…
We illustrate the progress of covariant QCD phenomenology for the description of meson coupling constants and form factors. As examples, we discuss the $\rho\pi\pi$ and $\gamma \pi\rho$ interactions, the $\rho$ contribution to the pion…
Electroproduction form factors describing the $\gamma^\ast p \to \Delta^+(1232), \Delta^+(1600)$ transitions are computed using a fully-dynamical diquark-quark approximation to the Poincar\'e-covariant three-body bound-state problem in…
This work presents a first study of a radiative calculation for the gravitational axial anomaly in the massless Abelian Higgs model. The two loop contribution to the anomalous correlation function of one axial current and two…
We discuss the reaction $\pi^- e^- \to \pi^- e^- \pi^{0}$ with the purpose of obtaining information on the $\gamma \pi \to \pi\pi$ anomalous amplitude ${\cal F}_{3\pi}$. We compare a full calculation at ${\cal O}(p^6)$ in chiral…
We propose to introduce the intrinsic transversal momentum distribution functions (iTMDs), in conjunction with the light-cone distribution amplitudes (LCDAs), to elucidate the probability amplitude of encountering a meson state wherein the…
The anomalous dimension $\gamma_m =1$ in the infrared region near conformal edge in the broken phase of the large $N_f$ QCD has been shown by the ladder Schwinger-Dyson equation and also by the lattice simulation for $N_f=8$ for $ N_c=3$.…
It is shown that a chiral quark model of the Nambu--Jona-Lasinio type can be used to describe "soft"-momenta parts of the amplitudes with large momentum transfer. As a sample, the processes \gamma^* --> \gamma (\pi,\eta,\eta') where one of…
We perform a chiral extrapolation of lattice data on the scalar K pi form factor and the ratio of the kaon and pion decay constants within Chiral Perturbation Theory to two loops. We determine the value of the scalar form factor at zero…