Studying minijets and MPI with rapidity correlations

We propose and carry a detailed study of an observable sensitive to different mechanisms of minijet production. The observables measure how the transverse momenta of hadrons produced in association with various trigger objects are balanced as a function of rapidity. It is shown that the observables are sensitive to the model parameters relevant for the minijet production mechanisms: low-p _T cutoff regulating jet cross-section, transverse distribution of partons in protons and parton distribution functions. We perform our test at different charge-particle multiplicities and collision energies. The Monte Carlo models, which describe many features of the LHC data, are found to predict quite different results demonstrating high discriminating power of the proposed observables. We also review mechanisms and components of Herwig, Pythia, and Sherpa Monte Carlo models relevant to the minijet production.