Einstein was right. We are pretty sure. The Universe is filled with massive things that interact by the gravitational force. Good. The Standard Model is predictive. It can be seen from the math in the Standard Model that there must be four particles that carry the Electro-Weak force. This seems true. Good.
The Standard Model is a quantum field theory. In quantum mechanics statistics play a central role. Objects have some probability to be in certain point in space-time carrying a mass within some mass-range and showing one out of many expected behaviors. Just like humans, in a way. The Standard Model predicts that these objects interact in particular patterns. By studying the different behaviors of an object, we can find out what particle we are dealing with and test the model.
The probabilities for a particular interaction to occur are only predicted in terms of the other parameters of the model. “If A happens ten times, B happens twenty times.” The numbers themselves need to be measured in experiments. The Standard Model has proven itself very believable when it predicted the Z-boson, which was later on explicitly measured in Geneva. A predictive model seems better than one that only explains Nature afterwards. You rather know the timetable of tomorrows than yesterdays trains.
But the Standard Model only works so well as long all the masses of the objects in the model are set to zero. But Einstein tells us mass exists in the Universe. And the Standard Model explains the fundamental particles of all. This does not go together. You could claim that we need to reinterpret General Relativity and set all masses in the Universe to zero. The outcome would highly interest me. No more diets ever! But physicists have tried to expand the Standard Model so that masses are allowed. This extension can be done and leaves the model unchanged enough to still explain Nature as far as we know it now. One iny-winy-tiny problem needs to be solved: the particle that is predicted in this extension, aka the Higgs-boson, needs to be found.
By the time it is found, don’t trust your physics friend who claims that (s)he is a little disappointed that Nature is as boring to do what we thought: we will be very relieved. We have no clue how to catch nature into formulas without the Standard Model and Higgs particle.
