OF NEGATIVE MASSES, BARE MASSES & BARE CHARGES:
Consider Newton’s law of gravitation and Coulomb’s electrostatic charge equation:
Both look similar and state that the force F between two objects is proportional to the product of their masses m or charges q, divided by the square of the distance r between them. However, the minus sign in Newton's equation is accepted as suggesting that two massive bodies attract each other while its absence in Coulomb’s law is accepted as suggesting that two similarly charged bodies repel each other. Secondly, the magnitude of the Coulomb's constant C is a very large number, 8.988 × 109 Nm2/C2, implying a strong force whereas Newton's constant G is a very small number, 6.670 × 10-11 Nm2/kg2, implying a weak force. Further, in Coulomb's equation, charge can be assigned both positive and negative values, and the electrostatic force can be either attractive or repulsive. In Newton's equation, mass is always positive, and the force is always attractive.
One scientist (http://www.lucastechnologies.com/cosmo.html) thought of using negative mass in a computer simulation to see how it turns out. He took some particles - half with positive mass and half with negative mass - threw them together in a computer simulation, and watched where they went. The results were surprising. The like particles tended to clump together and segregate themselves from the unlike particles with both types evolving quickly into all sorts of structures including clusters, filaments, sheets, and large voids. Indeed, it looked exactly like the distribution of galaxies in the large-scale survey maps. A control simulation using only positive mass particles produced a very nice globular cluster demonstrating that both types of matter were necessary to form the kinds of structures seen through the telescope. While a positive mass cluster produces a converging lens, distorting the background galaxies into concentric arcs, negative mass would produce a diverging lens, distorting the background galaxies into radial spokes.