In particle physics, energy is a measure of the ability of a particle or a system of particles to do work. It can exist in many forms, such as kinetic energy, potential energy, and rest energy.
In particle physics, the energy of a particle is typically measured in electron volts (eV) or joules (J). This can be done using various detection methods, such as calorimetry or particle tracking.
According to Einstein's famous equation, E = mc², there is a direct relationship between mass and energy. In particle physics, this means that particles with mass also have energy, and energy can be converted into mass and vice versa.
In some theories, particles can have negative energy. However, in most cases, the total energy of a system must remain positive to maintain stability and follow the laws of thermodynamics.
In particle interactions, energy is always conserved, meaning that the total energy before and after the interaction remains the same. This can involve the conversion of energy into different forms or the creation and annihilation of particles.