Related papers: The $\gamma^* \gamma^*\to\eta_c$ transition form f…
We show that the matrix element of a local quark-gluon operator in the photon state, $<\gamma(k\lambda)|\hat O| \gamma(k\lambda)>$, can be calculated in lattice QCD. The result is generalized to other quantities involving space-like…
We give an accurate determination of the vector (electromagnetic) form factor, $F(Q^2)$, for a light pseudoscalar meson up to squared momentum transfer $Q^2$ values of 6 $\mathrm{GeV}^2$ for the first time from full lattice QCD, including…
We use heavy quark effective theory (HQET) and perturbative QCD to study the heavy meson -- light vector meson transitions involved in D and B decays. HQET is used to relate the measured D -> K* l nu vector and axial-vector form factors at…
We compute the hadronic matrix element relevant to the physical radiative decay $\eta_{c}(2S)\to J/\psi\gamma$ by means of lattice QCD. We use the (maximally) twisted mass QCD action with Nf=2 light dynamical quarks and from the…
QCD sum rules are used to calculate the contribution of short-distance single-quark transition $s\rightarrow d \gamma$, to the amplitudes of the hyperon radiative decay, $\Omega^-\rightarrow \Xi^-\gamma$. We re-evaluate the Wilson…
In this paper, we calculate the Cabibbo-Kobayashi-Maskawa matrix element $|V_{ub}|$ by the semileptonic decay $B^+\to \omega\ell^+\nu$. For the transition form factors (TFFs) $A_1(q^2)$, $A_2(q^2)$, and $V(q^2)$ of $B^+\to \omega$, we…
In this paper, we study the $B \to K^*$ transition form factors (TFFs) within the QCD light-cone sum rules (LCSR) approach. Two correlators, i.e. the usual one and the right-handed one, are adopted in the LCSR calculation. The resultant…
A continuum approach to Quantum Chromodynamics (QCD), based upon Schwinger-Dyson (SD) and Bethe-Salpeter (BS) equations, is employed to provide a tightly constrained prediction for the $\gamma^{*} \gamma^{*} \rightarrow \{ \pi^0, \eta,…
We analyze the semileptonic $B \to a_1 \ell^+\ell^-$, $\ell=\tau, \mu, e$ transitions in the frame work of the three-point QCD sum rules in the standard model. These rare decays governed by flavor-changing neutral current transition of $b…
The tree level semileptonic $\Lambda_{b}\to pl\nu$ and $\Lambda_{c}\to nl\nu$ transitions are investigated using the light cone QCD sum rules approach in full theory. The spin--1/2, $\Lambda_{Q}$ baryon with $Q=b$ or $c$, is considered by…
The next-to-next-to-leading-order (NNLO) pQCD predictions for both the decay width and the transition form factor in the $\eta_c\rightarrow \gamma\gamma$ process, based on nonrelativistic QCD (NRQCD), deviate from precise experimental…
The axial N-> Delta(1232) transition form factors are calculated within the light cone QCD sum rules method. A comparison of our results with predictions of lattice theory and quark model calculations is pre- sented.
We consider the QCD sum rules approach for Delta-isobar magnetic form factor in the infra-red region $0<Q^2<1GeV^2$. The QCD sum rules in external variable field are used. The obtained formfactor is in agreement with quark model predictions…
In this work, we analyze the semileptonic decay processes of $\Lambda_b \to \Lambda_c$ in the light-cone sum rule approach. In order to calculate the form factors of the $\Lambda_b$ baryon transition matrix element, we use the light-cone…
The coupling constants g$_{\rho\eta\gamma}$ and g$_{\omega\eta\gamma}$ are calculated using QCD sum rules method by studying the three point ${\rho\eta\gamma}$ and ${\omega\eta\gamma}$ correlation functions. A comparison of the results with…
Relating the forward light-by-light scattering to energy weighted integrals of the \gamma* \gamma -fusion cross sections, with one real photon (\gamma) and one virtual photon (\gamma*), we find two new exact super-convergence relations.…
The leading Isgur-Wise form factor $\xi(y)$ parametrizing the semileptonic transitions $\Lambda_b\to\Lambda^{1/2}_{c1}\ell\bar\nu$ and $\Lambda_b\to\Lambda^{3/2}_{c1}\ell\bar\nu$ is calculated by using the QCD sum rules in the framework of…
The electromagnetic form factors of the nucleon, in the space-like region, are determined from three-point function Finite Energy QCD Sum Rules. The QCD calculation is performed to leading order in perturbation theory in the chiral limit,…
In this paper, we investigate the semileptonic decays $B_c \to \eta_c\ell\bar\nu_\ell$ using the quantum chromodynamics(QCD) sum rules within the framework of Standard Model (SM). We further explore the potential to probe signatures of new…
We present our recent results for the pion elastic form factor [1] obtained within a local-duality three-point sum rule (a Borel sum rule in the limit of an infinite Borel parameter). Our analysis includes the O(1) and O(\alpha_s)…