Pion production at large transverse momentum

A constituent interchange model is used to give a natural explanation of the observed energy dependence of ISR data for π° production at 90°. It is predicted that at large fixed p_T and sufficiently high energy the cross section will become constant, with a p_T dependence of (p_T²)^?2.5. It is also tentatively suggested that the e⁺e^? annihilation structure function $\text{ν}\text{W}{}_2$ should behave like ω^?1.5 near ω = 0.