small particles

[Enoch]

can someone explain the smaller particles, such as the quark, that make up the neutrons, electrons, and protons. (explain how they work)

[swansont]

Google and Wiki. Your friends in the digital age.

 

http://en.wikipedia.org/wiki/Quark

 

electrons are leptons, and thus not comprised of quarks. The electron is a fundamental particle.

[Enoch]

The electron is a fundamental particle.

 

meaning that all other particles are made of electrons?

[Klaynos]

The electron is a fundamental particle.

 

meaning that all other particles are made of electrons?

 

No, meaning that electrons are not made up of anything.

 

Protons and neutrons are made from quarks so are not fundamental particles.

 

Quarks are not made up of anything so are fundemental...

[foodchain]

The electron is a fundamental particle.

 

meaning that all other particles are made of electrons?

 

I think he means you cant dived the electron into more subatomic particles. The most "fundemental" particles I think share in that discription, though I could be wrong of course.

 

Here is an example from wiki.

 

"The neutron experiences the weak interaction through beta decay into a proton, electron and electron antineutrino. It experiences the gravitational force as does any energetic body; however, gravity is so weak that it may be neglected in most particle physics experiments.

 

The most important force to neutrons is the strong interaction. This interaction is responsible for the binding of the neutron's three quarks (one up quark, two down quarks) into a single particle. The residual strong force is also responsible for the binding of nuclei: the nuclear force. The nuclear force plays the leading role when neutrons pass through matter. Unlike charged particles or photons, the neutron cannot lose energy by ionizing atoms. Rather, the neutron goes on its way unchecked until it makes a head-on collision with an atomic nucleus. For this reason, neutron radiation is extremely penetrating and dangerous."

 

http://en.wikipedia.org/wiki/Neutron

[Enoch]

ok. so does that mean that electrons and quarks are the same?

in a fundamental sence?

[Klaynos]

ok. so does that mean that electrons and quarks are the same?

in a fundamental sence?

 

No, but they are both fundemental particles.

[swansont]

ok. so does that mean that electrons and quarks are the same?

in a fundamental sence?

 

No. We'd probably not have named them differently if they were the same. Electrons are leptons; leptons and quarks have different properties (e.g. spins are quantized differently)

[Norman Albers]

Enoch is seeking with righteous curiosity. I have been working to describe photons and electrons as excitations of the vacuum, the laws of which we know, IMHO, only dimly. I grope with inhomogeneous field ideas, assuming Nature is indeed unified, and that only our understanding is not.

[timo]

Leptons and quarks have different properties (e.g. spins are quantized differently)

Err... I might have misunderstood you, but:

- The only thing leptons and quarks have in common is their spin: 1/2.

- The striking property allowing to cast the spin-1/2 particles (the SM fermions) into the two distinct groups "leptons" and "quarks" is their color charge. Leptons carry a color charge of zero and therefore do not interact with the QCD gauge field (the gluons).

[Norman Albers]

I could show you one of my favorite lines in Dirac's little black book on QM. The first third of the book is his exposition, tight mathematical prose, followed by math presentation. Right in the middle of the first part he says, "I give here the quantum mechanics of things of mass m and charge e. These are the eigenvalues we always measure and so I use them!" (I paraphrase only lightly.)

[Severian]

I could show you one of my favorite lines in Dirac's little black book on QM. The first third of the book is his exposition, tight mathematical prose, followed by math presentation. Right in the middle of the first part he says, "I give here the quantum mechanics of things of mass m and charge e. These are the eigenvalues we always measure and so I use them!" (I paraphrase only lightly.)

 

Why is that line interesting? it sounds pretty ordinary to me.

[Norman Albers]

Dirac makes it clear that he is clueless as to why there are such entities. It seems to me that quantization of angular momentum, spin, is the easier phenomenon to understand because it comes out of spherical harmonic analysis. Dirac expressed his pleasure that the mechanics of spin-1/2 came out of his fermion wave mechanics: "This was a great surprise to me. I thought that simplest particle would naturally have a zero spin, and that a spin of a half would have to be brought in later as a complication..." He goes on to describe the Klein-Gordon equation developed by Pauli and Weisskopf as one dealing with several particles which are bosons.

[swansont]

Err... I might have misunderstood you, but:

- The only thing leptons and quarks have in common is their spin: 1/2.

- The striking property allowing to cast the spin-1/2 particles (the SM fermions) into the two distinct groups "leptons" and "quarks" is their color charge. Leptons carry a color charge of zero and therefore do not interact with the QCD gauge field (the gluons).

 

 

Mea culpa, I was thinking of the fractional charge of quarks. No idea of why my hands typed spin.

[Severian]

"This was a great surprise to me. I thought that simplest particle would naturally have a zero spin, and that a spin of a half would have to be brought in later as a complication..."

 

This is really a aesthetic question as to the definition of 'simplest'. The electron is perhaps the most 'obvious' particle in the world, but I am not sure I would call it the simplest. We have never seen a particle with zero spin, but if the Higgs boson exists, I think it is a much simpler particle than the electron. Indeed, any spin zero particle is simpler than the electron, in agreement with Dirac's original prejudice.