What Causes Mass? | Recent Nobel Prize Winner

[mwinaz]

I heard Higgs recently say that the Higgs field is only responsible for 1 percent of an object's mass. I think I've also heard recently that gluon pairs popping into and out of existence is responsible for 80% of an object's mass. I think this discovery was awarded a recent Nobel Prize.

I want to know what are the different contributions or causes of an object's mass. Not an easy question, but please discuss.

 

[pallidin]

...I think I've also heard recently that gluon pairs popping into and out of existence is responsible for 80% of an object's mass. I think this discovery was awarded a recent Nobel Prize.

Could you provide a source for that claim? Not that it's wrong, just would like to read it.

 

[mwinaz]

In this lecture at time 20:40, Lawrence Krauss says that 90% of the mass of a proton is from virtual particles coming into and out of existence within the empty space between quarks. Because objects are mostly made of protons and neutrons, 90% of object's mass is from this empty space between quarks.

http://www.youtube.com/watch?v=7ImvlS8PLIo&feature=player_embedded

Also here...

http://www.newscientist.com/article/dn16095-its-confirmed-matter-is-merely-vacuum-fluctuations.html

 

[pallidin]

Thanks, I will view it.

 

[mwinaz]

OK. So I'm thinking 90% of an object's mass is due to virtual particles popping into and out of existence from nothing. 1% is from Higgs. What is responsible for the other 9%?

 

[DLuckyE]

I'm confused, wouldn't that mean empty space has mass as well? Thought virtual particles popped in and out everywhere.

 

[mwinaz]

I'm confused, wouldn't that mean empty space has mass as well? Thought virtual particles popped in and out everywhere.

That is true - Maybe Krauss is referring to gluons?

 

[Kevin_Axion]

He's referring to this: http://www.newscientist.com/article/dn16095-its-confirmed-matter-is-merely-vacuum-fluctuations.html and http://www.sciencemag.org/cgi/content/abstract/sci;322/5905/1224. A thread has already been created that addresses this idea: https://www.physicsforums.com/showthread.php?t=273814

 

[karan1114]

never thought of mass coming from inside quarks

 

[daschaich]

I'm fond of this article by Brian Hayes in American Scientist, which addresses this issue in a non-technical way, and doesn't seem to have been mentioned in the previous thread. I think it is publicly accessible (I can't tell because the site recognizes my ip as an "Institutional Licensee"), but if not, the author http://bit-player.org/bph-publications/AmSci-2008-11-Hayes-QCD/AmSci-2008-11-Hayes-QCD.pdf a pdf on his Web site as well.

QCD computations have shown that the three quarks inside a proton account for only about 1 percent of the proton's measured mass; all the rest of the mass comes from the energy that binds the quarks together.

The "recent Nobel prize" is presumably that awarded to Gross, Politzer and Wilczek in 2004 for the discovery of QCD (or, technically, "for the discovery of asymptotic freedom in the theory of the strong interaction").

 

[pallidin]

I'm fond of this article by Brian Hayes in American Scientist, which addresses this issue in a non-technical way, and doesn't seem to have been mentioned in the previous thread. I think it is publicly accessible (I can't tell because the site recognizes my ip as an "Institutional Licensee"), but if not, the author http://bit-player.org/bph-publications/AmSci-2008-11-Hayes-QCD/AmSci-2008-11-Hayes-QCD.pdf a pdf on his Web site as well.



The "recent Nobel prize" is presumably that awarded to Gross, Politzer and Wilczek in 2004 for the discovery of QCD (or, technically, "for the discovery of asymptotic freedom in the theory of the strong interaction").

Going out-on-the-limb here, but is this to suggest gluon's have a direct and definitive role in what we know as "mass"?

 

[daschaich]

Going out-on-the-limb here, but is this to suggest gluon's have a direct and definitive role in what we know as "mass"?

You could probably say that, depending on what you mean by "role", what you mean by "direct" and what you mean by "definitive".

I joke, but I'm really not sure what exactly you're asking. As was discussed in the older thread Kevin_Axion linked, the role of the strong interaction in the mass of hadrons has been well-known for a long time.

 

[Kevin_Axion]

The total vacuum energy of virtual gluons and quarks/anti-quarks - which manifest and combine to form mesons and baryons momentarily constitutes the majority of the mass.

 

[inflector]

The total vacuum energy of virtual gluons and quarks/anti-quarks - which manifest and combine to form mesons and baryons momentarily constitutes the majority of the mass.

So basically, does this mean that there is no mass there, there is only energy which is seen as mass at the level of the protons, neutrons, etc. because it is bound inside the baryon?

 

[daschaich]

E=mc^2... where there's energy, there's mass. But maybe that's what you meant by "energy which is seen as mass".

 

[inflector]

But maybe that's what you meant by "energy which is seen as mass".

Yes, of course.

But we have this idea of particles that HAVE rest mass as a concept distinct from energy and that mass can be converted to energy using the above formula.

It seems like in the case of baryons, for example, that the energy is trapped inside the baryon in an energy state rather than in a particle-with-mass state. This is very different than the mass for the quarks themselves which is supposed to be something intrinsic that comes from interactions with the Higg's field.

Makes one sort of wonder if all mass isn't really energy trapped in some fashion inside the particles, even in the case of the quarks themselves and fermions, and that perhaps the line between mass and energy is not so distinct as we once thought.