Study of production mechanisms at large transverse momentum in pp→ppπ+π- at 28.5GeV/c

In order to explain the experimentally observed energy dependence of the chargedparticle multiplicity distribution (i) in pp collisions, it has been suggested (2) that there are at least two mechanisms at work in multiparticle production. One is the multiperipheral (short-range correlation), the other is the diffractive (long-range correlation) production mechanism. According to this model, one populates the central, the other the boundary region of rapidi ty space. However, two recent buble-ehamber experiments (a.4) have shown that at intermediate energies and low momentum transfer the dominant features of singleand double-pion production are different from the above picture (5). They indicate that the shortand long-range (reggeon and pomeron) exchanges are intertwined in a double peripheral graph. To investigate this problem we have studied four-constraint four-body final states at large p~ (~ 1 GeV/e), a region heretofore unexplored. The experiment was carried out at the Brookhavea National Laboratory AGS with the ~ul t ipar t ic le Argo Spectrometer System (MASS) (e). Using two of the three spectre-