Confirmed: E=mc^2 Validated Once Again, Despite Skepticism | PhysLink

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Actually, i don't quite get how the experiment tested E=mc². I am not at work this week so i cannot consult the Nature article, which i will be certainly doing next week.

Here is what i got out of the link:

When a neutron is captured by an atom, the total mass of the atom with one extra neutron is

[tex]m_{total} = m_{atom} + m_{neutron} - \frac{E_{binding}}{c^2}[/tex]

From experiment (with the magnetic traps, measuring the revolutions about the B field lines) they acquired the total mass (silicon ion with neutron) and the mass of a Silicon ion.

The [tex]E_{binding}[/tex] consists out of emitted gamma rays and a recoil energy of the nucleus. This is all straighforeward. They measured the gamma ray energy.

So from experiment we have both the gamma energy, the ionic mass and the mass of the ion WITH the neutron. In order to verify if E=mc², we need to have the [tex]E_{binding}[/tex], right ? Well, the one thing they are missing is the nuclear recoil. How did they deal with that ? Probably it was much smaller than their error margin ?

regards
marlon
 
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Am i the only guy that does not get the point of this article ?

marlon
 
the first experiment needed to know the recoil energy, I thought the second one didn't. I know nothing about this, and this is just a layman's guess.
 
tribdog said:
the first experiment needed to know the recoil energy, I thought the second one didn't. I know nothing about this, and this is just a layman's guess.

Well, i am thinking nearly the same thing. It must be that the recoil energy is smaller than the actual accuracy level (smaller spread in error) of the outcome of the experiment. Somehow, they must have proven that. If so, you do not need to know the actual value for this recoil energy.

Since nobody else is answering this, it seems i will have to wait until i obtain the Nature article on monday. This is very interesting though


regards
marlon
 
If the nuetron causes the nucleus to recoil wouldn't that heat the sample? Then, by knowiing the heat capacity, couldn't you measure the temperature to find out how much energy went into this process?