| a proton comprises 3 different kinds of quark bound together |
Over the decades the mass and size of the proton has been
determined with increasing accuracy and the received view of physicists has
been that they are both constant. For proton mass, this still holds; but for
proton size the situation changed with a measurement made in 2010 by Pohl et al
(Max Planck Institute, Germany) and published in Nature.
It had been determined that the diameter
of a proton was 0.87 femtometres (1 fm = 1 metre divided by a quadrillion, i.e.
a 1 followed by 24 zeros). It was always assumed that this was a constant property
of a proton throughout space and time, independent of the measurement method,
which was normally done using a hydrogen atom, which comprises a proton and an orbital
electron.
The method used in
2010 was a new one and involved focusing a fine laser beam onto a muonic
hydrogen atom. Like ordinary hydrogen this comprises a central proton of
positive charge attended by a negatively charged particle. In the case of
normal hydrogen the negative particle is an electron whereas with muonic
hydrogen it is a similar but heavier particle called a muon. The larger mass of the muon, 200x that of an
electron, would indirectly result in a more accurate measurement of proton size
than the method employing the usual electron. That was the reason for using it;
but the result was entirely unexpected: a 4% smaller radius.
No one has been able to find any fault in the methodology of
these new measurements and existing physics does not explain why the size of
the proton depends on whether an electron or a muon is accompanying the proton.
Does this mean that the photons in the laser beam interact with muons in a
fundamentally different way than with electrons? Maybe the Large Hadron
Collider will give a clue. The chase is on, one of many in modern physics that will
hopefully converge to reveal more of the splendour of God’s creation.
see also
http://arstechnica.com/science/2013/01/hydrogen-made-with-muons-reveals-proton-size-conundrum/
http://www.nature.com/news/shrunken-proton-baffles-scientists-1.12289
Radioactivity half life is not contant
Author of 2077 AD
