Abstract: It is well known that there is a tunneling effect in quantum mechanics．A particle can pass through
regions where its energy is lower than potential energy．In such a barrier region，the kinetic energy of the
particle is negative．The calculated transmission coefficient of the one-dimensional square barrier in quantum
mechanics textbooks have not yet been quantitatively verified experimentally．According to previous theoretical
analysis，in the barrier region，particles should follow the Schrdinger equation for negative kinetic energy，and
the expression of the negative kinetic energy of a particle is the usual expression of positive kinetic energy plus
a negative sign．In the barrier region，the momentum of the particle is still real rather than imaginary． We
propose an experimental scheme in which photons collide electrons in the barrier region to determine whether
the momenta of the electrons with negative kinetic energies in the barrier region are imaginary or real．
