If a neutron weighs 1.6749293E-27kg, a proton 1.6262171E-27kg, an electron 9.1093826E-31kg and an antineutrino is assumed massless (~0 kg), and given:
-Neutron decay --> electron + proton + antineutrio
-Neutron composed of 2 down quarks/1 up quark
-Proton composed of 2 down quarks/1 up quark
What accounts for the mass difference of 4.7801252E-29kg (or 52.47 times the mass of an electron) between the mass of the neutron and the sum of the masses of the proton and electron (given that the antineutrino is massless)?
What is the other "stuff" that I seem to be missing?
2006-12-28 13:14:18 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Physics
OK, the energy portion I knew. But "what" part did the energy come from? And if the isolated neutron has such a long half life (indicating relative stability) then why is there so much energy released?
2006-12-30 14:21:20 · update #1
The missing mass was the binding energy, which was released during decay. You know, this E = mc^2 business, equivalence of mass and energy.
2006-12-28 13:17:10 · answer #1 · answered by Scythian1950 7 · 1⤊ 0⤋
A couple things. First basically all a neutron is is a proton and an electron. I see that you realized there is some mass that is missing if you added these together, and your realization is accually pretty well thought out. What you are missing is energy.
Remember that according to relativity matter=energy. they are interchangeable. When a proton and an electron do fuse to form a neutron there is some energy given off and this energy does equate for the missing mass. Mathematically in high energy particle physics you will deal with some of these energys and as well in general particle physics. Not that I remember many of the formulas from either of those classes, but that is what you are missing the energy which is also mass.
2006-12-28 21:26:50 · answer #2 · answered by travis R 4 · 0⤊ 0⤋
Interestingly enough this neutron decay process was known before Einstein came up with e=mc^2, and people wondered the same thing you do. Albert came up with this equation in a completely unrelated way, but the energy releases corresponds to exactly the missing mass time the speed of light squared!
2006-12-28 21:21:29 · answer #3 · answered by Tony O 2 · 0⤊ 0⤋
An up quark has a charge of + 2/3.
A down quark has a charge of - 1/3.
A proton contains 2 up quarks and 1 down quark.
+ 2/3 + 2/3 = 1/3 = 1.
A proton has a charge of +1.
A neutron contains 2 down quarks and 1 up quark.
- 1/3 - 1/3 + 2/3 = 0
A neutron has no charge.
2006-12-28 21:46:52 · answer #4 · answered by Kevin H 7 · 0⤊ 2⤋
A neutron is fat and lazy. A proton is positive and does its best to hold the nucleus together(Lot's of stress).
2006-12-28 21:28:22 · answer #5 · answered by Glenn B 7 · 1⤊ 3⤋