Fitting procedures#
Fitting meson resonances#
Best overview of types of fits and theoretical motivations for each of those can be found in section “Resonances” of the PDG.
BESIII is a formation experiment.
See documentation for all RooFit parametrizations
here.
Single and double Gaussian#
Characterization of detector resolution(s).
Breit-Wigner parametrization#
Only works in case of narrow structure and if there are no other resonances nearby
Can be used to extract pole parameters such as particle width
Possible: energy dependent parameters
Convolution of a Breit-Wigner with a Gaussian is called a Voigtian (see RooVoigtian).
Flatté parametrization#
Analytical continuation of the Breit-Wigner parametrization
Does not allow for extraction of pole parameters, only ratios
Background shapes#
Polynomial ​
​Chebychev polynomial ​
​Argus background shape ​
Other literature#
Example scripts for RooFit (see overview of descriptions here)