Homework Help: Qns On Protons

1. May 17, 2006

Delzac

Hi,

Given that a " up " quark has charge of 2/3e ; a "down" quark has a charge of - 1/3e, where e is the elementary charge (+1.6 x 10^-19 C).

can is say that a proton contain 3 " up " quark and 1 "down" quark?

the charge in the end seems to add up to +1.

is what is have said correct?

p.s. i just started learning particle physics

2. May 17, 2006

neutrino

(3 x 2/3) + (1x(-1/3)) = 1?

Incase you meant 3 down quarks, then that doesn't work either - Add the masses of the quarks.

3. May 17, 2006

jhmar

Charge values are: u = +2/3; d = -1/3
2 up + 1 down = +1

Last edited: May 17, 2006
4. May 17, 2006

Delzac

sry i meant 2 " up" quarks and 1 " down" quark. does it work now?

5. May 17, 2006

Delzac

another thing i understand is that quarks isn't actually IN the proton itself isn't? so how can we say that to proton CONTAIN quarks IN it

6. May 21, 2006

disregardthat

7. May 21, 2006

dav2008

The proton is made up of quarks.

There aren't quarks "inside" of a proton because that implies there exists a structure called a proton independently of quarks.

Edit: Well I guess there are also gluons.

Last edited: May 21, 2006
8. May 21, 2006

Lyuokdea

Summing the masses wouldn't give you any useful information for finding the number of quarks in a proton or neutron, without a lot of extra information. The sum of the quark masses is only a small percentage of the mass of a proton.

~Lyuokdea

9. May 22, 2006

neutrino

I had this feeling that my teacher was wrong. :grumpy: I should've checked what he said, though. I stand corrected...Thanks.