question-What are the examples in which energy can be converted into mass?
answer-The first examples of energy turning into particles involved cosmic ray tracks in photographic emulsions. In order to increase the liklihood of an event, said emulsions were unusually heavy in silver bromide...the sensitive media. When it was determined fairly early on that the rays were bent in a magnetic field....indicating charged particles for at least some of them (they turned out to be mostly protons)...classification schemes began. Eventually they noticed that pairs of particles appeared at some collision vertices. The most common pair was electron/positron....energy creating matter pairs. Later, proton/ anti-proton pairs were found...then neutron/anti-neutron..etc.
What was never seen was sudden appearance of a single particle, or anti-particle....without it's commensurate partner. That's called associated production of pairs. In order to have the Big Bang create the universe as observed directly from energy, there has to be an asymmetry in the production of protons vs. anti-protons....and electrons vs. positrons...so that hydrogen atoms can form. As yet, nobody has ever seen this happen in a lab.
So from an experimental point of view there is scant evidence for the universe to exist...(the asymmetry in the decay rates of B mesons only points to a slight delay in BB theory getting down to the real problem....the exact match of one electron per proton observed in the universe). Your nuclear reactor comment is correct....some pairs(not solos) are seen there...more evidence for associated production.It's a problem asking for a more insightful answer.
jesmul again-The creation of atoms heavier than iron require that some energy be turned into mass. Usually the energy is provided by a supernova.
jesmul hiomself is confused-this question was rocking in my mind, not yet found example, but the activity in the nuclear reactor, there are some anti-particles, are they the example of it, that is energy converted into mass?
anurag jaib comments helped-Conversion of photon(energy) into electron-positron pair, two mass particles...
jesmul cont...-...yes , i am comming...just a trying to focus on the concept ''Annehilliation''----as Mr Aurang Zaib said Electron-Positron little mass will exist for little time......again the y wil turn to energy.......Particle physicists make this kind of reaction happen every day in laboratories. This accomplished by accelerating ordinary particles up to very high speeds, close to the speed of light, and smashing them into each other. In an interesting collision, the result is a spray of new particles, many of which may be heavier than the original pair that collided. The energy of motion of the original particles has contributed to creating new ones. Some of these new particles are very interesting and exotic! Most only live for a short time before decaying into more ordinary stuff.
It is in this way that scientists have found out what kinds of particles exist. The world is made up of stable particles, and we only know about the unstable ones because we have been able to create them in the laboratory out of the energy in the collisions.
There are rules of course. Whenever a particle is made, certain things have to add up. The energy has to add up, of course. The total electrical charge cannot change, and so when many kinds of particles are made, the same number of antiparticles must also be made (some particles are their own antiparticles so you can make one of these at a time. Photons are examples of this). Antimatter annihilates with corresponding matter particles, and the result is eventually photons, leaving no net new matter. ----I guess the examplle is correct....can we go for a better one..???
...yes , i am comming...just a trying to focus on the concept ''Annehilliation''----as Mr Aurang Zaib said Electron-Positron little mass will exist for little time......again the y wil turn to energy.......Particle physicists make this kind of reaction happen every day in laboratories. This accomplished by accelerating ordinary particles up to very high speeds, close to the speed of light, and smashing them into each other. In an interesting collision, the result is a spray of new particles, many of which may be heavier than the original pair that collided. The energy of motion of the original particles has contributed to creating new ones. Some of these new particles are very interesting and exotic! Most only live for a short time before decaying into more ordinary stuff.
It is in this way that scientists have found out what kinds of particles exist. The world is made up of stable particles, and we only know about the unstable ones because we have been able to create them in the laboratory out of the energy in the collisions.
There are rules of course. Whenever a particle is made, certain things have to add up. The energy has to add up, of course. The total electrical charge cannot change, and so when many kinds of particles are made, the same number of antiparticles must also be made (some particles are their own antiparticles so you can make one of these at a time. Photons are examples of this). Antimatter annihilates with corresponding matter particles, and the result is eventually photons, leaving no net new matter. ----I guess the examplle is correct....can we go for a better one..???
I spent a lot of time as an undergraduate working on an experiment in which Au197 nuclei were targeted with Gamma rays of various specific energies from 135MeV up to 160MeV, looking for Pions (140MeV) to be ejected from the Gold. We did observe this happening. Ultimately, this was a case where energy in the form of a gamma ray was converted into matter, in the form of a pion. There are MANY other experiments in which gammas hit something and new particles are released.
.............And SLAC and Fermilab and Brookhaven as well as several others. CERN isn't the only HEP lab out there.. The energy put into a particle by the accelerator is converted into new particles (mass) when the beam impacts the target or when a particle anti-particle collision occurs in a storage ring experiment. As an example, check out the live one event displays from Fermilab. All of those particles are created from the energy put into the colliding particle beams.
