We present the properties of the C parameter as an event shape variable. We calculate the coupling constants in the perturbative and also in the non perturbative part of the QCD theory, using the dispersive as well as the shape function model. By fitting the corresponding theoretical predictions to our data we find the values of coupling constant = 0.117 + 0.014 and , 0.491 + 0.043 for the dispersive model and the mean value of the coupling constant = 0.124 + 0.015 and lambda = 0.052 for the shape function model. our results are consistent with world average value of 0.118 + 0.002. We explain all these features in the main text.

Keywords