in a particle accelerator a proton and an antiproton, travelling at the same speed, undergo a head on collision and produce sub atomic particles a) the total kinetic energy of the two particles just before collision is 3.2 x 10^-10J I) what happens to the proton and anti proton during collision? my answer----Two pions are formed from an up anti down quark pair and an anti up down quark pair, leaving a down and an anti down quark which will annihilate to produce photon(s) is this right? it is just a guess. II) state why the total energy after the collision is more than 3.2 x 10^-10J i don't know. only thing i can think of is because some mass had been converted to energy, but i don't see how because when the photons are produced they are then travelling at the speed of light even if they have virtually 0 mass so by K.E=0.5mv^2 will K.E not be conserved? someone explain! (b) in another experiment the total K.E of the colliding proton and anti proton is greater than 3.2 x 10^-10J state two possible differences this could make to the subatomic particles produced. ths only thing i can think of is higher frequency photons but photons aren't subatomic particles so i am sunk=/. i don't know. Just so you know, this is a revision question i found myself, as opposed to homework ( i have exams in two weeks :surprise: ) so i am not just trying to find a cheap way of getting out of homework! i have looked in text books and notes but can't find anything useful and i'm worried!