Transverse-Momentum Correlations in Production Processes

A simple method to analyze two-particle correlations of transverse momenta in multiparticle final states is described. A clear physical interpretation of such correlations is presented, and a preliminary analysis of several reactions involving three and four body final states is reported. (Submitted to Phys . Rev.) * Work supported by the U. S. Atomic Energy Commission. Increasing machine energies have recently stimulated intense experimental and theoretical interest in multiparticle production processes. Much of this interest, however, has been focused on measuring multiplicities and studying similar properties of inclusive (a + b 4 c + anything) reactions. Theoretical models for production processes (parton, multiperipheral, multiregge, limiting fragmentation, etc.) have been used primarily to make either structural predictions such as scaling behavior or global and integrated predictions such as mean multiplicity as a function of energy, longitudinal distributions, and so forth. 1 Inclusive experiments do not generally allow direct detailed tests of basic model assumptions. The surfeit of information in these processes is difficult to digest because of the lack of a clear choice among the large number of possible sets of variables with uncertain physical interpretations. 2 The purpose of this letter is to indicate how study of two particle corrections in multiparticle production processes can yield new insights into, and experimental tests of, the underlying production mechanisms. Although the method can be applied to quite general processes, in particular, the bi-inclusive type (a + b -+ d + d + anything), we limit ourselves to three and four particle (exclusive) final state events for purposes of illustration. The generalization of the analysis to higher multiplicities and inclusive reactions will be clear and the details will be the subject of a future communication. A simple extension and combination of the multiperipheral and absorption models, in an impact parameter picture, will be used to suggest and parameterize correlations in the transverse momenta of two final state particles in the nonasymptotic region. 3 Our model is not meant to be taken very literally and it is probably not the only model that fits the data, but it does seem to work