Measured Against Reality

Monday, September 17, 2007

Old notion of the distribution of charge inside the neutron overturned

Apparently the old notion of the distribution of charge inside the neutron has been overturned:

For two generations of physicists, it has been a standard belief that the neutron, an electrically neutral elementary particle and a primary component of an atom, actually carries a positive charge at its center and an offsetting negative charge at its outer edge.

The notion was first put forth in 1947 by Enrico Fermi, a Nobel laureate noted for his role in developing the first nuclear reactor. But new research by a University of Washington physicist shows the neutron's charge is not quite as simple as Fermi believed.

Using precise data recently gathered at three different laboratories and some new theoretical tools, Gerald A. Miller, a UW physics professor, has found that the neutron has a negative charge both in its inner core and its outer edge, with a positive charge sandwiched in between to make the particle electrically neutral.


This is pretty cool, but I wanted to know how the quarks arrange themselves inside the neutron in order for this to happen. It would seem that the down quarks are at the center and outside and the up quark is in the middle, but that doesn't make much sense (since then the up would be in the middle). But then again I don't know much of anything about quantum chromodynamics, perhaps this does make sense.

One of the reasons I mentioned it here is because it's a good example of something we've believed for a while (in this case 60 years) being suddenly overturned. This was published in PRL, so I doubt it's junk, and it will probably be well-received by the Physics community (again, provided it does have good evidence going for it). It's always good to have examples of when a long-held belief is just overturned; it demonstrates the power, flexibility, and nondogmatic nature of science.

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1 Comments:

  • I am a physicist and I think we can avoid this topics again. During the years we were discussing this elements and I think it's time to understand the main fact behind all this reactors and its researches.

    By Anonymous Viagra Online, at 10:45 AM, May 25, 2011  

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