# Why do we assume a neutron has no electromagnetic charge?

If a neutron has a mass ($1.674929\times 10^{-27} kg$) and all mass is defined as energy in the formula $E=mc^2$, does that mean that a neutron has an electromagnetic charge but is overall neutral, or do we understand this as having absolutely no charge at all and only "nuclear" energy?

Is there any other evidence of this other than the fact that the electroweak force and electromagnetism does not effect the neutrons flow?

• As is, your questions is going to get down votes and votes to close (not mine) because we only deal with main stream physics, not unpublished personal theories. But "How do we know the neutron has no electric charge" is a good question. It get more answers if you remove all but the last sentence. – mmesser314 Jan 21 '17 at 13:35
• I have resolved this conclusively using various different methods of testing which have been proven more superior than general relativity measuring the nuclear decay in atomic clocks. Cold fission chamber producing fields with both negative and positive flows of energy. The explanation of polarization of movement on various ratios causing a skewed perspective of gravity, time and the nature of the universe. – Greg Goldberg Jan 29 '17 at 1:24
• @mmesser314 Good point. I think in general arguing for absolutely 0 charge is not possible without also invoking quantization of charge. I can't immediately see how Milikan's oil drop precludes a 'charge vacuum' of sorts between the electron charge and something much closer to zero. – Borun Chowdhury Feb 17 '17 at 15:13

It is an experimental fact that neutrons have no net charge. They have a magnetic dipole moment, which points to having charged constituents (quarks), the charges of which algebraically sum to $0$. (It is not the only evidence for constituents in the neutron: scattering experiments also indicate the presence of constituents, and exclude the possibility of the neutron as some kind of bound state of a proton-electron system.)

• No net charge in relation to what? I think you misunderstand the nature of "charge" and why we use it for both electrical charge, physical charge, a charge of heat etc. A charge is just movement at different ratios and all your deductions are theoretical. If anyone takes something of equal charge and run it down a split cable with positive on one end and negative on the other, the value of the charge will split too while harmonizing. I think you have a very skewed perspective on the physical world. – Greg Goldberg Jan 29 '17 at 0:33
• ??????????????? – ZeroTheHero Jan 29 '17 at 0:43
• This is mathematically evident and I have done the calculations which seem to make the atomic decay of a nuclear clock consistent with the time flow on earth. Just try the math with my equations and no universal constants, it is just a measure of the scalar height value which is a measure of entropy. – Greg Goldberg Jan 29 '17 at 1:22
• @GregGoldberg - What equations? You have provided no equations or evidence to support your arguments. – honeste_vivere Feb 17 '17 at 18:19

The fact that the electromagnetic force doesn't affect the neutron is precisely the evidence that the neutron has no charge, by definition. Electric charge is a measure of the interaction of an object with the electromagnetic field; if something has no charge then electromagnetism doesn't affect it, and vice verse. Someone else might be able to go into the experimental details, but this is the main point.

Regarding your first sentence: the formula $E=mc^2$ means that mass makes a contribution to energy, equal to $mc^2$ when the particle is at rest. This is completely unrelated to whatever charge the particle may have. And it makes no sense to say that something has a charge but is neutral: neutral means zero charge!

As an aside, your use of the words "assume" and "define" bothers me a little. We observe that the neutron has no charge. We observe (or deduce might be a better word) that the quarks have the charge they have and we also observe/deduce the quark composition of the neutron. But assumptions and definitions are math, not physics.

The standard model of particles was a theory which was hypothesized in middle of the 20th century. This theory has successfully predicted new particles as the theory improved and explained many experimental observations. Hence, it is deemed to be correct.

The standard model consists of 17 elementary particles (the particles cannot broken down further, i.e: these are fundamental and cannot be divided).

Source: Wikipedia

As you might have observed, the proton and neutron do not appear in the above diagram. This is because protons and neutrons are not elementary particles. These particles are made up of a combination of quarks.

If you go back to the table, you'll find that an up quark has $+\frac{2}{3}$ charge whereas a down quark has $-\frac{1}{3}$ charge.

A proton is made up of two up quarks and one down quark.

Net charge = $+2(\frac{2}{3}) - 1(\frac{1}{3}) = 1$

A neutron is made up of one up quark and two down quarks.

Net charge = $+1(\frac{2}{3}) - 2(\frac{1}{3}) = 0$

The proton has a net charge of $+1$ and then neutron has a net charge of $0$.