# Understanding the mass of ordinary matter

• I
Summary:
Conceptual and high level understanding of the mass to ordinary objects
Hello,
The periodic table contains 118 different elements which compose regular matter and the reality around us. On the other hand, "antimatter" is made of elements not included in the periodic table. As far as the periodic table, I think about 98 elements occur naturally while the other ones are man made. Now, ordinary objects are made of the different elements combined/bonded in different ways. Fundamentally, all elements are made of protons, neutrons, electrons. The total mass of an object is 45% from the neutron, 55% from protons and 0.03% from electrons. Neutrons and protons are made of quarks whose mass is only about 1% of the mass of the protons and neutrons. So all the mass that an object has is not due to the mass of the particles but to the energy stored in the fluctuations of the gluon field which binds quarks together (strong force).

The gluon field is essentially empty space (it has fluctuations) that it is not truly empty but filled with energy, correct? So, fundamentally, the mass of regular matter is mainly energy, as Einstein postulated. I read that the space between quarks has less fluctuations. Does that mean it contains more energy? Is my understanding correct?

Also, if most of the mass or ordinary things is truly a form of energy, what is the origin of the remaining mass? For example, if what is the 0.03% of the electrons' mass made of?

Thanks!

• Delta2

Paul Colby
Gold Member
Summary:: Conceptual and high level understanding of the mass to ordinary objects

On the other hand, "antimatter" is made of elements not included in the periodic table. As far as the periodic table,

Well, and anti-deuteron is made up of an antiproton and an antineutron. Take two anti-deuterons and two positrons and you make an anti-deuterium molecule. So, as far as I know, all elements of the periodic table have an anti- counterpart of the same mass.

Also an anti-X meets an X they may annihilate releasing energy equivalent to their mass.

• fog37
mfb
Mentor
Antimatter has the same periodic table with the same elements. Antihydrogen is routinely produced as neutral element (antiproton+positron), antihelium-nuclei have been produced as well.
The gluon field is essentially empty space
It's not empty. If it would be empty it wouldn't have energy.
I read that the space between quarks has less fluctuations.
I don't know what you read, it sounds strange, but without seeing the source I can't tell.

The mass of the elementary particles in matter comes from their interaction with the Higgs field.

• fog37 and vanhees71
vanhees71
Gold Member
Most of the mass of ordinary matter around us, concentrated mostly in the protons and neutrons of the atomic nuclei, does not come from the interaction with the Higgs field but through the not yet completely understood mechanism of confinement, i.e., via the strong interaction.

• Delta2, fog37 and Paul Colby
In special relativity, we call rest mass ##m_{rest}## the mass of an object that is at rest relative to the reference frame (observer). Rest mass and energy are related through the famous equation below: $$E=m_{rest} c^2$$ Based on our discussion above, the mass of any ordinary object is the rest mass. And the majority of the rest mass ##m_{rest}## is fundamentally energy related to gluon field, quark confinement, etc., Only a small portion of the rest mass is due to the Higgs field mechanism.

So also the small amount of rest mass due to the Higgs field mechanism is equivalent to energy, correct? The rest mass ##m_{rest}## in the above equation does not specify a particular type of mass and its origin and just includes all rest mass. Is that correct? So, in summary, the rest mass consists of a portion (the majority) due to the strong force and a minor portion due to the Higgs field mechanism. But both are fundamentally the same type of energy...

• Delta2
Delta2
Homework Helper
Gold Member
Allow me to jump in, the mass that generates gravity is from the Higgs mechanism, the confinement mechanism or from both?

vanhees71
Gold Member
The source of the gravitational field, according to general relativity, is not mass but the energy-momentum-stress tensor. In GR inertia and the source of the gravitational interaction are due to energy, momentum, and stress rather than due to inertial and gravitational mass as in Newtonian physics, which explains within GR, why inertia and sources of the gravitational field are the same by construction (implementing the strong equivalence principle).

Delta2
Homework Helper
Gold Member
The source of the gravitational field, according to general relativity, is not mass but the energy-momentum-stress tensor. In GR inertia and the source of the gravitational interaction are due to energy, momentum, and stress rather than due to inertial and gravitational mass as in Newtonian physics, which explains within GR, why inertia and sources of the gravitational field are the same by construction (implementing the strong equivalence principle).
I am not sure i understand this, and how exactly it answers my question. Since the source of the gravitational field is energy, this energy comes from the higg's field and from the strong force field?

• Imager
vanhees71
Gold Member
The source of the gravitational field is the energy-momentum tensor of all the non-gravitational fields, describing matter and radiation. Part of it is also the Higgs field. For the matter surrounding us the contribution of the Higgs field to the mass of the protons and neutrons is about 2% of their total mass. Most of the mass is due to the strong interaction, as already kind or explained above. One should, however, keep in mind that confinement of QCD is not fully understood yet.

• Imager and Delta2
Delta2
Homework Helper
Gold Member
the contribution of the Higgs field to the mass of the protons and neutrons is about 2% of their total mass.
Elementary particles have all their mass due to the higgs mechanism. Is that correct? But composite particles like proton and neutron, have most of their mass due to the confinement mechanism. Is that correct?

Staff Emeritus
No. Positronium gets its mass from the Higgs mechanism.

• vanhees71
Delta2
Homework Helper
Gold Member
Positronium is kinda of exotic. When i was saying composite particle i had in mind some sort of particle consisting of other particles held together by the strong force. But ok that was good to mention, you made me realize that there are composite particles that are hold together by other forces other than the strong force.

Thank you all. Just so I can follow, if a book has a mass of ##m_{rest}=5 Kg##, that represents its rest mass and we know it is equivalent to an amount of energy equal to ##E = m_{rest} c^2##. That different portions of that rest mass has two different origins which are the Higgs mechanism and QCD confinement.

While in SR, ##m_{rest}## represents a simple scalar parameter, in GR the concept of mass has a more sophisticated and different meaning...

Last edited:
vanhees71
Gold Member
All things discussed have very little to do with GR.

mfb
Mentor
Positronium is kinda of exotic. When i was saying composite particle i had in mind some sort of particle consisting of other particles held together by the strong force. But ok that was good to mention, you made me realize that there are composite particles that are hold together by other forces other than the strong force.
It's still not true in general. If you take particles that contain heavy quarks then most of their mass comes from these heavy quarks. Hadrons with only light quarks (like protons, neutrons and pions) are the outlier here.

• vanhees71