Thursday, May 10, 2018

Weak Nuclear Force Measured by Physicists For The First Time

 In an international effort between scientists called the Jefferson Lab Q-weak Collaboration, scientists have for the first time provided a precise measurement of the nuclear weak force. This the force between protons and electrons, capable of transforming neutrons into protons through nuclear decay.
 Through this experiment, the value of 0.0719 (plus or minus 0.0045) was measured from the asymmetry in the scattering of polarized electrons on protons. However, this task has been always been difficult considering how the weak force is so much more sparing than the electromagnetic force.
 To get an accurate measurement, the scientists took advantage of a discovery in the 1950s. Most aspects in physics follow a resemblance of symmetry or balance, where changing certain features of the Universe would not make a significant difference. However, the weak force demonstrates an inherent left and right bias in the breakdown of particles involved in this force.
 Spinning electrons in one of two directions and launching them at protons causes them to ricochet off in a precise fashion, depending on the direction or helicity of their spin. This difference between the two possible helicity configurations made it possible to get accurate measurement of the weak force.

Read more about this fascinating story at: https://www.sciencealert.com/proton-weak-force-measurement-experiment-uses-parity-violation
Or read the full study at: https://www.nature.com/articles/s41586-018-0096-0


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