Higher-twist contribution to meson pair production in hadron collisions

The contribution of higher-twist mechanisms to π+ π−,K+K− and ρ° ρ° production in high-energy\(\bar p\)p collisions, with the two mesons emitted back to back at 90° in the c.m. frame and at moderate or largepT, has been calculated and compared with the minimal-twist contribution, i.e. double jet fragmentation. The signal/background ratio is shown to depend critically on Δp, a parameter defining the upper limit for non-detection of accompanying particles; and, to a lesser extent, on the meson wave function. It is shown that, while there is little hope for checking higher-twist contributions in pion pair production, such contributions may show up clearly in kaon and rho pair production. In the last case, it may be possible to use polarization effects, in addition to cross-section measurements, in order to show the occurrence of higher-twist mechanisms.