Study of four-jet events and evidence for double parton interactions inpp¯collisions ats=1.8TeV

Kinematic properties of four-jet events produced in $p\overline{p}$ collisions at $\sqrt{s}=1.8\mathrm{}$ TeV have been studied using data with an integrated luminosity of 325 ${\mathrm{nb}}^{-1\mathrm{}}$ collected using the Collider Detector at Fermilab during the 1988-1989 Fermilab Collider run. The individual jet $p_T$ spectra and the angles between each jet pair are compared to the predictions of leading-order quantum chromodynamics for the double gluon bremsstrahlung process and good agreement is observed. In addition, a search for double parton scattering has been undertaken using variables sensitive to the topology of four-jet events. A small double parton content provides the best description of the data. We find $\frac{N_{\mathrm{DP}}}{N_{\mathrm{DB}}}={5.4}_{-2.0\mathrm{}}^{+1.6\mathrm{}}\%$, where $N$ represents the number of events attributed to each process. We measure ${\sigma }_{\mathrm{DP}}={63}_{-28\mathrm{}}^{+32\mathrm{}}$ nb for jets having $p_T>25\mathrm{}$ GeV/c in the pseudorapidity interval $\left|\eta \right|<\mathrm{}3.5\mathrm{}$.