Universality of Short Range Nucleon Correlation in Deep Inelastic Proton and Antiproton Production off Nuclei

Despite significant progress made over the past decade, the structure of nuclear matter at short internucleon distances remains one of the least studied problems in nuclear physics. At distances of the order of the nucleon size, nuclear matter is represented by compact groups of correlated nucleons, called short range correlations, with relative momenta exceeding the Fermi momentum. These objects are produced for short periods of time by fluctuations in the average nuclear density when two or more nucleons get together within the distance of about 1 fermi. One of the important characteristics of the correlations is their universality, which implies the independence of their properties from the mass number of the nucleus. Therefore, the features of these nuclear structure objects reflect the properties of nuclear matter rather than specific nuclei. Information about short-range physics is mainly extracted from the analysis of processes with large energy-momentum transfers. In this letter we present the results of a reanalysis of data on the production of high momentum protons and antiprotons on nuclei in the virtually unexplored kinematic region of large energy-momentum transfers in the region where main contribution to the cross sections comes from three-nucleon correlation. For the first time in hadron induced reactions we observed the existence of the correlations universality in the creation of proton and antiprotons, which consist exclusively of quarks or antiquarks, respectively. The analysis conducted indicates a change in the proton formation mechanism from quasi-elastic to deep inelastic scattering with an increase in the energy-momentum transferred to the detected cumulative protons.