15,002 research outputs found
Two-photon and two-gluon decays of p-wave heavy quarkonium using a covariant light-front approach
In this paper, a study of two-photon and two-gluon decays in the context of
p-wave heavy quarkonia is presented. Within the covariant light-front
framework, the annihilation rates of scalar and tensor quarkonium states are
derived. In the absence of free parameters in this case, the results for the
charmonium decay widths are consistent with the experimental data. However, in
comparison to other theoretical calculations, there are large discrepancies in
our results regarding bottomonia.Comment: 19 pages, 3 figures, 3 tables, some typos are corrected, version to
be published in Phys. Rev.
Heat-kernel approach for scattering
An approach for solving scattering problems, based on two quantum field
theory methods, the heat kernel method and the scattering spectral method, is
constructed. This approach converts a method of calculating heat kernels into a
method of solving scattering problems. This allows us to establish a method of
scattering problems from a method of heat kernels. As an application, we
construct an approach for solving scattering problems based on the covariant
perturbation theory of heat-kernel expansions. In order to apply the
heat-kernel method to scattering problems, we first calculate the off-diagonal
heat-kernel expansion in the frame of the covariant perturbation theory.
Moreover, as an alternative application of the relation between heat kernels
and partial-wave phase shifts presented in this paper, we give an example of
how to calculate a global heat kernel from a known scattering phase shift
- …