What is the definition of beam energy in particle physics?

For example, the proton beams in the LHC collider have 7 TeV energy. Does this mean that the individual protons in the beam have 7 TeV energy or that the energy of all the protons in the beam add up to 7 TeV?

Collision experiments are done to create particles that can not be studied under normal circumstances. Energy and momentum conservation as well as the famous Einstein equation $$E=mc^2$$ tell us that a heavier particle can not just "pop out of thin air". But if we let two particles with enough energy collide, they can create a new particle, if the incoming energy is high enough. Therefore the individual particles in the collision beam need to have a high energy.