Related papers: Light-by-light forward scattering sum rules for ch…
We derive a set of sum rules for the light-by-light scattering and fusion: $\gamma\gamma \to all$, and verify them in lowest order QED calculations. A prominent implication of these sum rules is the superconvergence of the…
We generalize a forward light-by-light scattering sum rule to the case of heavy quarkonium radiative transitions. We apply such sum rule to the bottomonium states, and use available data on radiative transitions in its evaluation. For the…
We present a set of sum rules relating the low-energy light-by-light scattering to integrals of \gamma\gamma-fusion cross sections and use them to study the hadronic contributions.
We apply a sum rule for the forward light-by-light scattering process within the context of the $\phi^4$ quantum field theory. As a consequence of the sum rule a stringent causality criterion is presented and the resulting constraints are…
We employ QCD sum rules, implemented with two numerical algorithms already tested in two different channels of Charmonium, in order to predict masses of resonances just above the ground states in the $^3 P$ channels. We find that such…
In the past decade, due to the experimental observation of many charmonium-like states, there has been a revival of hadron spectroscopy. In particular, the experimental observation of charged charmonium-like, $Z_c$ states, and…
We present our preliminary results on the calculation of hadronic light-by-light forward scattering amplitudes using vector four-point correlation functions computed on the lattice. Using a dispersive approach, forward scattering amplitudes…
The hadronic contribution to the eight forward amplitudes of light-by-light scattering ($\gamma^*\gamma^*\to \gamma^*\gamma^*$) is computed in lattice QCD. Via dispersive sum rules, the amplitudes are compared to a model of the…
The heavy-quark QCD sum rules are applied to a model of charmonium based upon the gauge/gravity duality. We find that there is strong agreement between the moments of the polarization function calculated from the holographic model and the…
Using the charmonium light-front wavefunctions obtained by diagonalizing an effective Hamiltonian with the one-gluon exchange interaction and a confining potential inspired by light-front holography in the basis light-front quantization…
In this work a comprehensive analysis of the mass spectrum and decay properties of charmonium states within a relativistic framework is carried out. The present experimental status of charmonium states is reviewed. Utilizing a screened…
In this study, we utilize light-cone QCD sum rules at twist-3 accuracy to compute the coupling parameters of the $\chi_{c1}(2P)$ state with $D$ and $D^*$ mesons. The analysis reveals that the observed $\chi_{c1}(3872)$ meson incorporates…
We bound EFT coefficients appearing in $2 \to 2$ photon scattering amplitudes in four dimensions. After reviewing unitarity and positivity conditions in this context, we use dispersion relations and crossing symmetry to compute sum rules…
We consider the problem of an harmonic oscillator coupled to a scalar field in the framework of recently introduced dressed coordinates. We compute all the probabilities associated with the decay process of an excited level of the…
The radiative decay $ B_{q}^*\to B_{q}\gamma(q=u,d, or s) $ is reexamined with a modified light-cone QCD sum rule method, in which adequate chiral operators are chosen as the interpolating fields in the correlators used for a sum rule…
We evaluate the light baryonium spectrum, viz. the baryon-antibaryon states, in the framework of QCD sum rules. The nonperturbative contributions up to dimension 12 are taken into account. Numerical results indicate that there might exist…
We evaluate the light-quark meson contributions to three exact light-by-light scattering sum rules in light of new data by the Belle Collaboration, which recently has extracted the transition form factors of the tensor meson $f_2(1270)$ as…
The method of QCD sum rules in the presence of the external electromagnetic $F_{\mu\nu}$ field is used to analyze radiative decays of charmed or bottomed mesons such as $D^{\ast}\to D\gamma$ and $B^{\ast}\to B\gamma$, with the…
Prompted by several potential tetraquark states that have been reported by the LHCb, CMS and ATLAS collaborations in the di-$J/\Psi$ and $J/\Psi \Psi(2S)$ spectra, we investigate their contribution to two-photon processes. Within a…
Infrared divergences have long been heralded to cancel in sufficiently inclusive cross-sections, according to the famous Kinoshita-Lee-Nauenberg theorem which mandates an initial and final state sum. While well-motivated, this theorem is…