Cutting-edge science builds upon the science that preceded it. It is disconcerting if such foundation science needs to be readjusted. The entire universe is composed of so-called fundamental particles, including the electron, neutron and proton.
Scientists have believed that simple parameters such as particle size, mass and charge were well-established for decades. Recent research, however, has called into question some of those set-in-stone parameters — what parameters are researchers questioning, and what are the consequences?
The Radius of the Proton
According to Discovery Communications, scientists believed the radius of a proton was 0.8768 femtometers (1 femtometer = 10⁻¹⁵ meters) for years. How did they measure this radius? It was no simple problem; they took indirect measurements via electrons. One fact that suggests this might not have been the best method of measurement is that electrons are extremely light in comparison to the proton.
We could compare the old method for measuring protons via electrons to using a foot-long ruler to measure miles; it’s not the most logical measuring device. Researchers have now devised a seemingly superior method, using another elementary particle; the much heavier, negatively charged, muon. Using the muon method, the proton’s radius measured only 0.84087 femtometers – a shocking 4 percent difference.
Measuring Protons: Out With The Old, In With The New?
Should texts replace the old result with the new result? Not without thorough investigation as to the reason for the changes. Researchers need to understand the reasons for the large difference, and fully prove that the new method is more accurate. The new measurements may represent an improvement, but the changes could possibly be due to experimental error, calculation error, inappropriate methodology, or even particle interaction discrepancies.
Additional testing and the use of an alternate method of measurement may resolve the difference. The consequence may be additional insight with readjustment to the Standard Model theory. Since scientists no longer consider the proton a fundamental particle, but think it represents the composite of three quarks and a gluon, there may be further implications affecting these, as well.
Supersymmetry and the Sphericity of the Electron
Late in the 20th Century, researchers proposed a theory that would expand the world of the particle physicist — ‘supersymmetry’. Additional particles that would come out of supersymmetry could help explain the astronomical puzzle of the missing matter or so-called ‘dark matter’, as it remains unseen. It is itself controversial. If the theory of supersymmetry is true, it means that the shape of the electron should be something less than perfectly spherical.
Scientists at the Large Hadron Collider have sought confirmation of supersymmetry. However, Harvard and Yale physicists have determined that the shape of the electron is even more spherical than might have been anticipated. In actuality, this was not the first blow to the theory. There was also the Large Hadron Collider discovery of an ultra-rare decay of so-called ‘beauty particles’ that supports the Standard Model but deprecates supersymmetry.
Lack of Supersymmetry, Protons and Electrons: Changes to Physics
Clearly one consequence of a lack of supersymmetry to the physicist and the astrophysicist alike must be the sobering thought that supersymmetry advocates may wish to expend future effort along different lines. It may be better not to spend further time trying to reinvent a theory that so far has not only failed, but has added evidence to support the Standard Model.