>>      Particle Physics, although not LHC :-) Neutrino Physics.

     Something like 10^18 neutrinos cross everyone of us ( depends on 
individual size :-) ), comming from the thermonuclear reactor at the 
core of the sun. We catch a few hundreds of them per day in a 100t 
detector (depends on energy threshold we can reach). They essentially 
cross everything, including the big mass of the sun so that they reach 
us 8mn after they have been emitted. Similarly, nuclear power plants 
emit a lot of antineutrinos, so that we can detect a few of them. In 
both cases they get transformed on their way - which is a simple proof 
that they have a mass.

     Didier