Pion form factor and its asymptotic behaviour

A simple phenomenological formula is constructed, consistent with the basic principles, providing a definite freedom in the choice of asymptotic behaviour and reflecting all experimentally known features of the pion form factor. The formula is used to test the asymptotic behaviour of the pion form factor both in spacelike and timelike regions simultaneously. The present experimental data require the fall-off t^–2, which differs from the quark model prediction.On leave of absence fromInstitute of Physics, Slovak Acad. Sci., 899 30 Bratislava 1, Czechoslovakia.One of the authors (S. D.) would like to thank ProfessorAbdus Salam, the International Atomic Energy Agency and UNESCO for hospitality at the International Centre for Theoretical Physics, Trieste, where the final part of this work was done.