The P-Brane Theory is similar to the string theory, but more complicated. It states that the fabric of space in our universe is not one dimensional, like the string theory, but is present in 10 or 11 dimensions. Most of these are said to be curled up into very small, invisible shapes that we do not notice due to their small sizes. We only notice the ones that are large, flat, and are present in 1st, 2nd, 3d, and 4th dimensions. P- Brane's can also explain the black hole emissions. As a particle enters a black hole, it excites the p-branes present around the event-horizon and makes them ripple outwards. As the crest of one ripple meets the crest of another, they reinforce each other to form one large crest. A small piece of this crest breaks off and is thought to be emitted from the black hole.
Not enough is known about the P-Brane theory and so many people do not accept it. For now, without any substantial proof, it will remain just another one of the many exotic theories.