# How is it then when you colide 2 protons

1. Feb 25, 2010

### clm321

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?

2. Feb 25, 2010

### Dmitry67

Re: protons

because the number of particles is not conserved.

3. Feb 25, 2010

### clm321

Re: protons

ok well that didnt help me at all. what does that even meen im no genious

4. Feb 25, 2010

### Dmitry67

Re: protons

then explain what exactly you see strange in "you find a bunch of different particles"

5. Feb 25, 2010

### SpectraCat

Re: protons

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.

6. Feb 25, 2010

### the_house

Re: protons

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.

7. Feb 25, 2010

### clm321

Re: protons

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

8. Feb 25, 2010

### Dmitry67

Re: protons

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 :)

9. Feb 25, 2010

### clm321

Re: protons

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

10. Feb 25, 2010

### SpectraCat

Re: protons

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).

11. Feb 25, 2010

### Dmitry67

Re: protons

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"

12. Feb 25, 2010

### clm321

Re: protons

ok so is it the heat created by colliding protons that forms other particels?

13. Feb 25, 2010

### clm321

Re: protons

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?

14. Feb 25, 2010

### Dmitry67

Re: protons

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.

15. Feb 25, 2010

### clm321

Re: protons

ok do they ever colide nuetrons?

16. Feb 25, 2010

### Dmitry67

Re: protons

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.

17. Feb 25, 2010

### clm321

Re: protons

can someone tell me what every thing stands for in that math?

18. Feb 25, 2010

### SpectraCat

Re: protons

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.

19. Feb 25, 2010

### Dmitry67

Re: protons

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

20. Feb 25, 2010

### Matterwave

Re: protons

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.