https://doi.org/10.1140/epjc/s10052-018-6438-0
Regular Article - Theoretical Physics
Helicity amplitudes in 
decay
1
Department of Physics, Liaoning Normal University, Dalian, 116029, China
2
Departamento de Física Teórica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigación de Paterna, Apartado 22085, 46071, Valencia, Spain
* e-mail: dailr@lnnu.edu.cn
Received:
6
September
2018
Accepted:
10
November
2018
Published online:
19
November
2018
We use a recent formalism of the weak hadronic reactions that maps the transition matrix elements at the quark level into hadronic matrix elements, evaluated with an elaborate angular momentum algebra that allows finally to write the weak matrix elements in terms of easy analytical formulas. In particular they appear explicitly for the different spin third components of the vector mesons involved. We extend the formalism to a general case, with the operator 
, that can accommodate different models beyond the Standard Model and study in detail the reaction for the different helicities of the 
. The results are shown for each amplitude in terms of the 
parameter that is different for each model. We show that 
is very different for the different components 
and in particular the magnitude 
is very sensitive to the parameter, which suggest to use this magnitude to test different models beyond the standard model. We show that our formalism implies the heavy quark limit and compare our results with calculations that include higher order corrections in heavy quark effective theory. We find very similar results for both approaches in normalized distributions, which are practically identical at the end point of 
.
© The Author(s), 2018
