s-channel helicity conservation in elastic processes

The unitarity equation for elastic partial-wave amplitudes is considered. Defining helicity-total-flip elastic amplitudes as those in which both helicities change sign, it is observed that the unitarity equation strongly suggests that the imaginary part of the helicity-total-flip partial-wave amplitude is much smaller than that of the nonflip amplitude at high energies. Appealing to a plausibility argument, the ratio of helicity-total-flip to helicity-nonflip partial-wave amplitudes is estimated to be ${\left(\frac{1}{s}\right)}^{\frac{1}{2}}$ or smaller. The implications of this result for the full amplitude, the possibility of extending the result to other amplitudes if factorization is true, and the implications for Regge theory are discussed.