14,626 research outputs found
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
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.
The nature of states from a combined analysis of and
With a combined analysis of data on and in an effective field theory approach, we determine resonance
parameters of states in two scenarios. In one scenario we assume that
states are pure molecular states, while in the other one we assume that
states contain compact components. We find that the present data favor
that there should be some compact components inside associated
with the molecular components. By fitting the invariant mass spectra of
and , we determine that the probability of finding the
compact components in states may be as large as about .Comment: Discussions added, version published in EPJ
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