https://doi.org/10.1140/epjc/s10052-014-2723-8
Regular Article - Theoretical Physics
Angular distributions of the polarized photons and electron in the decays of the 
state of charmonium
Department of Physics, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
* e-mail: wkmok@hkbu.edu.hk
Received:
2
October
2013
Accepted:
23
December
2013
Published online:
4
February
2014
We calculate the combined angular-distribution functions of the polarized photons (
and 
) and electron (
) produced in the cascade process 
, when the colliding 
and 
are unpolarized. Our results are independent of any dynamical models and are expressed in terms of the spherical harmonics whose coefficients are functions of the angular-momentum helicity amplitudes of the individual processes. Once the joint angular distribution of (, ) and that of (, ) with the polarization of either one of the two particles are measured, our results will enable one to determine the relative magnitudes as well as the relative phases of all the angular-momentum helicity amplitudes in the radiative decay processes 
and 
.
© The Author(s), 2014
