An example of how OPloT can be used, is shown below (to test the plot, go to "OPloT test" in the menu above). Here you can manually input invariant masses of dileptons or dimuons, and the tool plots them for you. You can adjust the number of bins and choose between logarithmic and linear x-axis. The four regions are also adjustable. The mean value and width of the four regions are shown in the table to the far right, for dielectrons and dimuons separately.