Apr 11, 2023 04:47 PM
(This post was last modified: Apr 11, 2023 04:55 PM by C C.)
https://www.quantamagazine.org/the-elect...-20230410/
INTRO: Imagine an electron as a spherical cloud of negative charge. If that ball were ever so slightly less round, it could help explain fundamental gaps in our understanding of physics, including why the universe contains something rather than nothing.
Given the stakes, a small community of physicists has been doggedly hunting for any asymmetry in the shape of the electron for the past few decades. The experiments are now so sensitive that if an electron were the size of Earth, they could detect a bump on the North Pole the height of a single sugar molecule.
The latest results are in: The electron is rounder than that.
The updated measurement disappoints anyone hoping for signs of new physics. But it still helps theorists to constrain their models for what unknown particles and forces may be missing from the current picture.
“I’m sure it’s hard to be the experimentalist measuring zero all the time, [but] even a null result in this experiment is really valuable and really teaches us something,” said Peter Graham, a theoretical physicist at Stanford University. The new study is “a technological tour de force and also very important for new physics.” (MORE - details)
From 2011: "After three months of experiments in a basement laboratory in London, scientists can confirm – with more confidence than ever – that the electron is very, very round. [...] The concept of shape might seem obscure when it comes to a subatomic particle, but the rules are the same as for everyday objects. Pick up a pen, for example, and you feel its shape because electrons in the pen push back against the electrons in your hand. And so it is with the electron itself. The particle is negatively charged, and the more evenly distributed the charge is around the centre of the particle, the more spherical it appears to be."
From 2019: "That electrons have both positive and negative charges puzzled reader Bruce Mason. 'Is the electron a composite particle? Where do the positive parts come from?' he asked. The electron is negatively charged, but the elementary particle never exists by itself, says Yale University physicist David DeMille. Electrons are always surrounded by clouds of 'virtual' particles that constantly wink in and out of existence. Such clouds contain particles with positive and negative charges. Researchers look at the electron and its cloud as one composite object. 'My favorite analogy is the Pig Pen character from Charlie Brown — if you see him from far away, you can’t see the cloud of flies and dust around him, but you might notice that his shape is different than that of a typical person,' DeMille says."
INTRO: Imagine an electron as a spherical cloud of negative charge. If that ball were ever so slightly less round, it could help explain fundamental gaps in our understanding of physics, including why the universe contains something rather than nothing.
Given the stakes, a small community of physicists has been doggedly hunting for any asymmetry in the shape of the electron for the past few decades. The experiments are now so sensitive that if an electron were the size of Earth, they could detect a bump on the North Pole the height of a single sugar molecule.
The latest results are in: The electron is rounder than that.
The updated measurement disappoints anyone hoping for signs of new physics. But it still helps theorists to constrain their models for what unknown particles and forces may be missing from the current picture.
“I’m sure it’s hard to be the experimentalist measuring zero all the time, [but] even a null result in this experiment is really valuable and really teaches us something,” said Peter Graham, a theoretical physicist at Stanford University. The new study is “a technological tour de force and also very important for new physics.” (MORE - details)
From 2011: "After three months of experiments in a basement laboratory in London, scientists can confirm – with more confidence than ever – that the electron is very, very round. [...] The concept of shape might seem obscure when it comes to a subatomic particle, but the rules are the same as for everyday objects. Pick up a pen, for example, and you feel its shape because electrons in the pen push back against the electrons in your hand. And so it is with the electron itself. The particle is negatively charged, and the more evenly distributed the charge is around the centre of the particle, the more spherical it appears to be."
From 2019: "That electrons have both positive and negative charges puzzled reader Bruce Mason. 'Is the electron a composite particle? Where do the positive parts come from?' he asked. The electron is negatively charged, but the elementary particle never exists by itself, says Yale University physicist David DeMille. Electrons are always surrounded by clouds of 'virtual' particles that constantly wink in and out of existence. Such clouds contain particles with positive and negative charges. Researchers look at the electron and its cloud as one composite object. 'My favorite analogy is the Pig Pen character from Charlie Brown — if you see him from far away, you can’t see the cloud of flies and dust around him, but you might notice that his shape is different than that of a typical person,' DeMille says."