# Mass: Causes, Sources & Relativity Explored

• B
• Ganoash
In summary, The cause of mass is a complex topic that involves both the Higgs field and the principle of least action. Protons and neutrons acquire their mass from a combination of the Higgs field and the QCD vacuum condensate. The popular description of binding energy in protons is incorrect, as binding energy is negative in any bound system. The interaction strength between quarks tends to a small but nonzero value at short distances, according to recent lattice QCD results.
Ganoash
hey guys,

what is the cause of mass?

in my understanding the elementary particles directly derive their mass from the higgs-field, and protons and neutrons get their mass from the (potential?) energy in between the up and down particles chained up within the protons and neutrons. my question is: a. how much of this is correct
b. I need some sources on this, where can I find them
c. if this is correct does that mean that I'm heavier when I'm running than when I'm standing still?
d, and if c is true does that mean that mass is relative since there should not be a preferred frame of reference for things like velocity etc.
(I know there is such a thing as rest mass but what I mean is, if I measured the mass of something, and someone who is going at 0,1C relative to the measured object measures the mass of something, would they measure a difference?(

thanks!
-ganoash

bhobba and Ganoash
Last edited by a moderator:
Ganoash said:
protons and neutrons get their mass from the (potential?) energy in between the up and down particles chained up within the protons and neutrons.

I think this popular description is in fact incorrect. It basically says that binding energy of proton is positive. But binding energy of any bound system is negative.

I'd say that quarks acquire a bit of mass from Higgs (just like electron does), and additionally about 350 MeV of mass from QCD vacuum condensate. When uud quarks combine into a proton, they lose a bit of mass (as they should, since any bound system has negative binding energy).

nikkkom said:
I think this popular description is in fact incorrect. It basically says that binding energy of proton is positive. But binding energy of any bound system is negative
I think one has to be very careful with such generalisations. "Binding energy" usually refers to the energy required to separate the constituents, which is a meaningless concept in QCD.

dextercioby and bhobba
Jilang said:
Binding energy for nucleons reduces the mass, but works the opposite way for the colour charge and increases the mass.

"Increases the mass" of what? There is no such object as "bare u quark with ~3 MeV mass".

Last time I checked, we can't fully correctly calculate QCD yet.

For a long time it was long thought that quarks are asymptotically free, that their interaction strength goes to zero with energy increase (= decrease in distance), but recently lattice QCD results become sufficiently precise and they seem to indicate that at short distances, quark interaction strength tends to a small but nonzero value. And IIUC this is not a problem, actually. Past theories based on asymptotic freedom hypothesis don't actually need it to tend to exactly zero.

Do we know for sure that energy of proton goes to infinity if you pull its quarks apart? It seems to me that a large but finite value would work too, in practice this would cause the same hadronization as in infinite case, matching observed experimental results.

## 1. What is mass?

Mass is a measure of the amount of matter in an object. It is a fundamental property of an object and is often measured in kilograms (kg) or grams (g).

## 2. What causes mass?

Mass is caused by the presence of subatomic particles, such as protons, neutrons, and electrons, within an object. These particles have mass and contribute to the overall mass of an object.

## 3. What are the sources of mass?

The sources of mass are the subatomic particles that make up an object. These particles can originate from within the object itself or can be acquired through interactions with other objects or particles.

## 4. How is mass related to energy?

In accordance with Einstein's famous equation, E=mc², mass and energy are equivalent and can be converted into one another. This means that mass can be converted into energy and vice versa.

## 5. How does mass affect relativity?

Mass is a key component in Einstein's theory of relativity. The more massive an object is, the more it curves the space-time around it, affecting the motion of other objects in its vicinity. Additionally, the theory of relativity explains how mass and energy are related and how they can affect the fabric of space-time.

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