# Mass-Energy: Particle Behavior & Properties

• gamow99
The mass energy of a photon is 1*10^-18 eV/c^2, the mass energy of an electron is .5 MeV/c^2, the mass energy of an up quark is 2.3 MeV/c^2, and the mass energy of a down quark is 4.8 MeV/c^2. In summary, these quantities represent the potential for these particles to do work, such as participating in particle reactions or interacting with electromagnetic fields. However, the specific behavior of a particle cannot be inferred solely from its mass energy. Other factors, such as its momentum and interactions with other particles, also play a role.

#### gamow99

The mass energy of a photon is 1*10^-18 eV/c^2
The mass energy of an electron is .5 MeV/c^2
The mass energy of an up quark is 2.3 MeV/c^2
The mass energy of a down quark is 4.8 MeV/c^2

I don't understand what these quantities enable to the particle to do. If we know these quantities then what can we infer about the particles behavior?

gamow99 said:
The mass energy of a photon is 1*10^-18 eV/c^2

This looks like an experimental upper bound. Photons are assumed to have zero mass.

Particle masses can be used in several fashions, for example to see if a decay or a particle reaction is kinematically allowed or to compute the trajectory of a particle in an electromagnetic field.

Orodruin said:
Particle masses can be used ... to compute the trajectory of a particle in an electromagnetic field.

Could you go into more details? Are you saying that mass-energy can be used to predict motion? If a down quark nears an up quark what quantities predict its movement? Does a photon have zero mass or zero mass-energy? I'm pretty sure that the photon only interacts with an electron. If so what happens when a photon near an neutrino or a quark?

I think you need to ask a more specific question. Suppose I asked this:

The mass of a fly is about .01 g
The mass of a herring is about 500 g
The mass of a giraffe is about 1500 kg
The mass of a sperm whale is about 13000 kg

I don't understand what these quantities enable to the animal to do. If we know these quantities then what can we infer about the animals' behavior?

You probably wouldn't know where to begin, right? Same problem here.

gamow99 said:
I don't understand what these quantities enable to the particle to do.
It let's them do the same thing as any other form of energy: work.