Horseless carriages were not "realistic"
Light that didn't come from the fire or sun was not "realistic"
Flying was not "realistic"
The very notion of germs was not "realistic"
Splitting atoms (hell, the very notion of atoms) was not "realistc"
The first four are things that were able to be determined by a single person, because the technology needed to overcome those things was simple enough.
However, what you're asking for is simply not realistic. Nuclear fission is not something a single person can undertake, nor is it easy -- but it is easily one of the biggest discoveries of the last century. Breaking protons apart into their discrete pieces may turn out to yield the biggest discoveries of this century, but to do so cannot be done by one or two enterprising individuals.
The technology involved in science of this scale (and at this point in our technological development) is simply not possible without large funding and large groups of very knowledgeable people.
Ok so this particular problem requires large scale everything, understood, but again we're back to the same question. What is this big discovery of the century that you speak of?? And WHY would it be the discovery of the century? If it's because of the magnitude and scale of the experiment then no it wouldn't be revolutionary.
Regarding your examples as to what were realistic.
The horse carriage is certainly a realistic invention, just like a flying car is a realistic invention. We don't have a flying car yet, but we will.
Light, well if it comes from fire and from the sun and is associated with heat, all basic observable phenomenons, a normal intelligent person would conclude that maybe light could come from other "things" too and there might be heat involved.
Flying, well birds can fly and some others can almost fly like chickens, basic observations. If fish can swim maybe we can swim too? If birds can fly maybe we can fly too if not now maybe sometime in the future?
Germs, let's see we have big animals, small animals, and tiny insects...hmmm...is it possible that there a micro organisms aka germs? Very possible.
So basically colliding particles will yield a tiny piece of a large puzzle. This piece we don't even know what it is or if it exist hence this experiment. If we don't find it then we will need to do more experients because we still would not be able to conclude that it doesn't exist. In other words anyting we find would not realistic.....ok....is that an answer? No because an aswer is not possible...ok...thanks anyway.