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clm321
Feb25-10, 09:39 AM
if a proton is a particle itself how is it then when you colide 2 protons in hte large hadron colider you find a bunch of different particles?

Dmitry67
Feb25-10, 09:51 AM
because the number of particles is not conserved.

clm321
Feb25-10, 09:52 AM
ok well that didnt help me at all. what does that even meen im no genious

Dmitry67
Feb25-10, 10:04 AM
then explain what exactly you see strange in "you find a bunch of different particles"

SpectraCat
Feb25-10, 10:07 AM
ok well that didnt help me at all. what does that even meen im no genious

Your statement indicates that you think a particle is a discrete object. A rock is also a discrete object .. but when you bang two rocks together, you can break them into smaller rocks if you hit them hard enough.

the_house
Feb25-10, 10:08 AM
It just means that the number of particles does not have to stay the same. Although particle number is often conserved in a non-relativistic system (not enough energy to break particles apart or create pairs of particles), it definitely is not conserved in a high energy collision at the LHC. This is unlike energy, which is conserved, so the total energy is the same before and after a collision.

Edit: Man, I'm slow! Two replies while I was typing this up.

clm321
Feb25-10, 10:11 AM
ok that helps a little more but ill try to explaine my question a bit better.

if protons are made up of 3 quarks how do all the other particles fit into the proton.
you can fit a boulder into pea. thats kinda what im getting at

Dmitry67
Feb25-10, 10:15 AM
they dont fit
you think about the collision as protons are breaking into smaller parts, previously existed inside them. this is incorrect

They are transformed into other particles.

For example, neutron can decay

n -> p + e- + neutrino

but at the same time, an opposite reaction is possible in some conditions

p -> n + e+ + (anti)neutrino

so if you try to think using your logic, proton consists of neutron and something, while neutron consists of proton and something :)

clm321
Feb25-10, 10:18 AM
that makes ALOT more sence thank you but how can they transform into other particles? and could you explain the math that you just showed im really bad and stll trying to learn the math

SpectraCat
Feb25-10, 10:18 AM
ok that helps a little more but ill try to explaine my question a bit better.

if protons are made up of 3 quarks how do all the other particles fit into the proton.
you can fit a boulder into pea. thats kinda what im getting at

The words "boulder" and "pea" have definite implications about relative size .. what about the words "proton" and "quark" makes you think there are any similar size implications? Anyway, even if there *were* relative size implications .. the strong nuclear force is .. STRONG! Ever see a snake in a can trick? The snake is way bigger than the can, but you can still compress it and stuff it inside the can. So you could visualize the 3 quarks as being "stuffed inside" the protons, and the collision releases them (I am not saying this is physically correct .. it is just an analogy to help you visualize the situation).

Dmitry67
Feb25-10, 10:20 AM
In QM *all* kinds of reactions are possible
*unless* they are violate some laws.
So in QM it is more logical to ask "why this reaction is not possible" then "why that reaction is possible"

clm321
Feb25-10, 10:30 AM
ok so is it the heat created by colliding protons that forms other particels?

clm321
Feb25-10, 10:34 AM
so when 2 protons colide it basicly melts down for a very breif second and form the other particles? do these other particles also have there own set of quarks?

Dmitry67
Feb25-10, 10:40 AM
Well, quarks collide independently.
It is easier to analyze the collision of 2 electrons, because they are structure-less.
You also can get a bunch of new particles.

clm321
Feb25-10, 11:05 AM
ok do they ever colide nuetrons?

Dmitry67
Feb25-10, 11:16 AM
you are asking if electron can collide neutron?

take any reaction I wrote above, for example:

n -> p + (e-) + (anti-v)

move electron to the right part as if it was a variable. You get:

n + (e+) -> p + (anti-v)

note that electron must be very energetic to 'feel' individual quarks in normally neutral neutron.

clm321
Feb25-10, 11:22 AM
can someone tell me what every thing stands for in that math?

SpectraCat
Feb25-10, 11:25 AM
ok do they ever colide nuetrons?

Neutrons are harder because they are not charged particles, therefore it is very difficult to control their trajectories. I suspect neutron-neutron collisions have been recorded as secondary events, but I don't actually know if they have been able to "break apart" neutrons in such a fashion. Most of the information comes from proton-neutron collisions, where a slow-moving thermal neutron is impacted by a relativistic proton.

Dmitry67
Feb25-10, 11:38 AM
can someone tell me what every thing stands for in that math?

n neutron
p proton
e- electron
e+ positron
v - neutrino

Matterwave
Feb25-10, 04:17 PM
As one of my professors once put it, "In regular life, if you collide two cars together, you get 2 mashed up cars, but in QM you can collide two cars together and get out a goat..." (I'm paraphrasing here)

It's weird like that. As long as the energy, charge, lepton number, etc, are conserved.