Related papers: Annihilation Rate of Heavy 0^{++} P-wave Quarkoniu…
We present a relativistic calculation of two-photon decays for heavy and light mesons in the framework of the Salpeter equation for quark-antiquark states. The meson-photon-photon vertex is computed by reconstructing the Bethe-Salpeter…
Rigorous QCD predictions for decay rates of the P-wave states of heavy quarkonia are presented. They are based on a new factorization theorem which is valid to leading order in the heavy quark velocity and to all orders in the running…
In this work we calculate the mass spectrum of charmonium for $1P,...,3P$ states of $0^{++}$ , $1^{++}$, as well as for $1S,...,4S$ states of $0^{-+}$, and $1S, ...,5D$ states of $1^{--}$ along with the two-photon decay widths of ground and…
We study the charmonium ($c\bar{c}$) and bottomonium ($b\bar{b}$) spectra, using Cornell potential with additional constant potential term in a non-relativistic framework, with spin-dependent corrections corresponding to the spin-spin,…
We compute S-wave and P-wave electromagnetic quarkonium decays at order v^7 in the heavy-quark velocity expansion. In the S-wave case, our calculation confirms and completes previous findings. In the P-wave case, our results are in…
Contributions to the decay rates of P-wave charmonium states that are proportional to $n_f \alpha_s^3$, where $n_f$ is the number of flavors of light quarks, are calculated in the framework of nonrelativistic QCD using the threshold…
As double heavy quarkonia, charmonium and bottomonium are generally considered to have small relativistic corrections and can be treated using nonrelativistic models. However, this is not always the case. In this paper, we employ the…
Radiative E1 decay widths of $\rm X(3872)$ are calculated through the relativistic Salpeter method, with the assumption that $\rm X(3872)$ is the $\chi_{c1}$(2P) state, which is the radial excited state of $\chi_{c1}$(1P). We firstly…
The ratio of the photon mediated production or annihilation rates of spin triplet and spin singlet heavy quarkonium states is computed to the next-to-next-to-leading logarithmic accuracy within the nonrelativistic renormalization group…
We show that perturbation theory may give reasonable numbers for the decays of the bottomonium and charmonium ground states to $e^+e^-$ and to $\gamma\gamma$. To reach this conclusion it is important to perform the resummation of logs. In…
The light-front approach is a relativistic quark model and offers many insights to the internal structures of the hadronic bound states. In this study, we apply the covariant light-front approach to ground-state heavy quarkonium. The…
We study the correction to the radiative $\pi^0$ decay width due to finite light quark mass. Using lattice QCD with the overlap fermion formulation, we calculate the three-point function of the form $<PV_\mu V_\nu>$ in the (Euclidean)…
The $P$-wave charmonium decays $h_{c}\rightarrow\gamma\eta^{(\prime)}$ are revisited by taking into account relativistic corrections. The decay amplitudes are derived in the Bethe-Salpeter formalism, in which the involved one-loop integrals…
Rates of the two-, three-, four- and five-photon annihilations of the electron-positron pairs are determined numerically for the three-body positronium ion Ps$^-$ ($e^- e^+ e^-$) and four-body bi-positronium `molecule' Ps$_2$ ($e^- e^+ e^-…
Two-body open charm strong decays of the $2P$ and $3P$ charmonium states are studied by the Bethe-Salpeter(BS) method combined with the $^3P_0$ model. The wave functions and mass spectra of the $2P$ and $3P$ charmonium states are obtained…
Using a data sample of 24.5 million psi(2S) the reactions psi(2S)->gamma chi_cJ, chi_cJ->gamma gamma have been studied for the first time to determine the two-photon widths of the chi_cJ states of charmonium in their decay into two photons.…
Hadronic annihilation decay rates of P-wave heavy quarkonia are given to next-to-leading order in both $\alpha_s$ and $v^2$. They include ten nonperturbative parameters, which can be rigorously defined as the matrix elements of…
We present a new factorization theorem for the decay rates of P-wave states of heavy quarkonia. Infrared logarithms that had appeared in previous perturbative calculations of P-wave decays are absorbed into a quantity that is related to the…
Hadronic annihilation rate of $1^{+-}$ heavy quarkonium is given to next-to-leading order in $\alpha_s$ and leading order in $v^2$ using a recently developed factorization formalism which is based on NRQCD. The result includes both the…
The decay widths of S-wave quarkonia ($\etc,\etb\to \gg{~~and~~} \J,\U\to\ee$) are calculated on the basis of a quasipotential approach. The nontrivial dependence on relative quark motion of decay amplitude is taken into consideration via…