Some things don't bounce like rubber balls do. For example, books don't bounce much when dropped.
Why is it that some things bounce while others don't?
[Physics] Why don’t all objects bounce like rubber balls
collisionnewtonian-mechanics
Related Solutions
When the player hits the ball with top spin, it makes the ball, well, spin.
By spinning, the ball will modify the airflow around itself and thus create an air pressure profile which will deflect the ball : this is the Magnus effect.
So by applying top spin on the ball the way tennis players do, the ball is rotating in the direction of the trajectory. This will bend the trajectory downwards. If you look at the ball's speed as a vector, the vertical component of the top-spun ball's velocity is greater than the normal served ball.
You simply direct the ball more vertically into the ground with a top spin. So after contact with the ground, the ball with top spin will leave the ground more vertically than a normal ball.
Since you are familiar with the sport, you might also have noticed that after contact, the top-spun ball will slightly accelerate towards you. This comes from the fact that part of its rotation has transfered itself into horizontal momentum. If you let a spinning ball fall vertically on the ground, after contact, it will fly out flat in some direction. I think this is also one of the reason why top spin serves are so hard to handle.
Elastic collisions do happen at the LHC. The TOTEM experiment measures the differential cross section (rate as a function of angle) for proton-proton elastic scattering at the LHC. Here is their latest result. They don't publish an estimate of the elastic cross section, but according to their data it must be at least 25 mb (millibarns) (my first version of this post had a mistake--the headline 100 mb number shown in the abstract is a measure of the total pp cross-section which includes both elastic and inelastic contributions). Compare this to the production cross-section of the Higgs boson at the same collision energy, which is about 20 pb (picobarns). This means that when two protons collide at 8 TeV, they are over a billion times more likely to bounce off each other than they are to produce a Higgs boson.
As others have pointed out, the general-purpose detectors like CMS and ATLAS are not designed to detect the elastic collisions. The elastic collisions occur mostly at forward angles, meaning the protons are just barely deflected from their original trajectory (think of a glancing collision between two billiard balls rather than a head-on collision), while the more exotic physics tends to produce particles that go more perpendicular to the beam direction.
Best Answer
Because bouncing requires the object to be elastic - shortly after it deforms, its shape should return to the one it had before deforming.
In order for an object to bounce1, the sequence of events would be following:
If all the above steps are passed, the object has to "un-deform" - internal energy gained because of deforming and not lost in the step 3 is turning back into the kinetic energy. Now it has its kinetic energy back, and thus has the speed to go up again.
In order to bounce, an object must "pass" all the steps above.
In other words, the objects bounces, if there is deformation and it's elastic, not plastic or viscous and most of the elastic potential energy is realised into acceleration of the whole object in the opposite direction.
Let's see consider three different objects - a rubber ball, a plasticine ball and a book, and see how they behave.
Well, any of them can pass the first step since they have got the speed. Now they will fall on the ground.
Balls pass the second step, they deform to a different degree. A book primarily fails to bounce because its shape favours other modes of energy propagation - dissipation via vibration. Thus, the book is not a contender anymore.
What about the third step? The plasticine ball fails it - its gained internal energy was mostly lost because of being transformed into thermal energy.
So, out of three objects, only the rubber ball will bounce.
As an additional example, you could consider the third, steel ball (not drawing it here :). It would certainly deform less than the rubber ball, but would still bounce pretty good.2
1 - This answer is considering a system where the surface of the floor doesn't deform itself. If there's a trampoline instead of the floor and an object won't stick to it once it falls on it, it will bounce back. If there's sand instead of hard surface, any object falling in sand would behave like an object which falls on the hard surface and fails the 3rd step
2 - See "Clarifying the actual definition of elasticity. Is steel really more elastic than rubber?"