
What's inside a proton? - georgecmu
http://physics.stackexchange.com/q/81190/25561
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elux
_You may have heard that a proton is made from three quarks. Indeed here are
several pages that say so. This is a lie — a white lie, but a big one. In fact
there are zillions of gluons, antiquarks, and quarks in a proton. The standard
shorthand, “the proton is made from two up quarks and one down quark”, is
really a statement that the proton has two more up quarks than up antiquarks,
and one more down quark than down antiquarks. To make the glib shorthand
correct you need to add the phrase “plus zillions of gluons and zillions of
quark-antiquark pairs.” Without this phrase, one’s view of the proton is so
simplistic that it is not possible to understand the LHC at all._

[http://profmattstrassler.com/articles-and-
posts/largehadronc...](http://profmattstrassler.com/articles-and-
posts/largehadroncolliderfaq/whats-a-proton-anyway/)

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mladenkovacevic
I've been having discussions about this with my brother about this recently
(who is a million times smarter than me) and it's remarkable to me that all
throughout school we think of matter at real, solid stuff we see around us
while subatomic particles are virtual abstractions used to describe the solid,
real stuff. I never could've understood quantum field theory in those days
(and still probably don't for the most part), but from what I do understand
it's turned my previous "knowledge" upside down - EVERYTHING is made up of
fields or pure mathematical structures, even the empty space around us, and
it's the matter and particles which we can see and feel that is a virtual
abstraction made up of those fields.

~~~
agumonkey
I recently came to this point of view. What surprised me is how much more
natural and organic fields feel to me. Much much closer to our perception of
the world than some geometrical abstraction you start with. Almost wish school
taught that first.

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acqq
The best answer is from David Z, which is still not the top one.

~~~
yk
The deleted answer was actually a great point, it was basically a nitpick on
the first sentence of David Z's answer.

    
    
        A proton is really made of quantum fields.
    

The problem with this statement is, that a observed object is said to be made
of a mathematical abstraction. So in a way, this is saying that a raytracer is
made of C. If we look into the ELF binary, we will find shell code, if we look
at the computer very closely we will find electrical signals, but we will only
find C in the reverse engineered source code. So similarly, the statement
should probably read:

    
    
        A proton is described as made of quantum fields. 
    

However, it is still important to remind everybody, that the popular analogy
of high energy physics, particles which interact much like billiard balls, is
a somewhat leaky abstraction. And this question is probably more a expression
of this leaking than a question of fundamental physics. If we would make the
classical analogy, that a proton is (described as) a stable field
configuration, then we would probably not have the question.

~~~
Sharlin
I think it depends on which philosophical school of though you subscribe to.
One could just as well argue that the concept of a "proton" is just a useful
abstraction and the quantum field is not just a mathematical tool but a more
fundamental model of the underlying reality - that ontologically, the field is
what actually exists.

~~~
yk
Actually I am a Kantian idealist, who experienced QFT calculations. On the
other hand, I have no first hand experience of a proton. So yes, I stand
corrected.

But empiricism dictates, that the experiment is correct and the theory is just
a description of the experiment. And if we discard empiricism, then we can not
really talk about physics anymore.

~~~
emmelaich
I love the idea of someone having "no first hand experience of a proton" :-)

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SaberTail
One of my professors was fond of saying, "the proton is a garbage dump," to
emphasize the mess of gluons and virtual quarks that you see when you start to
probe the proton.

It's also worth noting that the in the LHC, which collides protons, most of
the interesting collisions are due to gluons interacting, rather than the
quarks.

