Аннотация
In this work, the mixing angle of the vector [Formula: see text] and [Formula: see text] mesons is estimated in the framework of Nambu–Jona-Lasinio model. The decay [Formula: see text] is considered as a basic process to determine this angle. The obtained value is compared with the results of the other authors. Besides, the width of the decay [Formula: see text] and the cross-section of the process [Formula: see text] are calculated by using this angle.