"Perfect" Electron Roundness Bruises Supersymmetry 150
astroengine writes "New measurements of the electron have confirmed, to the smallest precision attainable, that it has a perfect roundness. This may sounds nice for the little electron, but to one of the big physics theories beyond the standard model, it's very bad news. 'We know the Standard Model does not encompass everything,' said physicist David DeMille, of Yale University and the ACME collaboration, in a press release. 'Like our LHC colleagues, we're trying to see something in the lab that's different from what the Standard Model predicts.' Should supersymmetrical particles exist, they should have a measurable effect on the electron's dipole moment. But as ACME's precise measurements show, the electron still has zero dipole moment (as predicted by the standard model) and is likely very close to being perfectly round. Unfortunately for the theory of supersymmetry, this is yet another blow."
Re:Invisible unicorns in a garage (Score:5, Informative)
Re:What about size? (Score:2, Informative)
radius: 2.8179403267e-15 m
surface: 9.9786881e-29 m^2
volume: 9.3731159e-44 m^3
above in fuzzy logic: very tiny
Re:Time for some really new physics (Score:5, Informative)
Although there has long been a connection between math and physics, as people dig further into the math they are finding some unexpected things, and ways to better understand, simplify, or extend the equations.
Mathematicians Link Knot Theory to Physics [nytimes.com]
A Jewel at the Heart of Quantum Physics [simonsfoundation.org]
There are a number of seemingly promising developments out there that are sharpening the investigative tools as well as providing interesting new lines of investigation, as well as new data to chew on.
Spooky Connection: Wormholes and the Quantum World [discovery.com]
Physicists Create Quantum Link Between Photons That Don't Exist at the Same Time [sciencemag.org]
Schrodinger’s ‘Kitten’? Large-Scale Quantum Entanglement Achieved By Two Physics Labs [planetsave.com]
String theorists squeeze nine dimensions into three [sciencenews.org]
New work gives credence to theory of universe as a hologram [phys.org]
Now we are developing a growing understanding of the interplay between biology and physics.
Quantum biology: Do weird physics effects abound in nature? [bbc.co.uk]
Who knows where things may lead next? Of course people should be careful in performing experiments.
Collapse of the universe is closer than ever before [phys.org]
Re:Once again way over my head, but... (Score:5, Informative)
The deviations they are talking about aren't things like mountains or bumps, but a systematic non-spherical bias.
For example, the earth isn't spherical either, it's basically a bit fatter around the equator pretty close to an oblate spheroid (e.g., an M&M is a more exaggerated oblate spheroid). Like a baseball, if the electron isn't totally spherical, you can detect a systematic bias as it's being thrown around (you can think of the LHC as throwing an electron spit-ball or a knuckle-ball).
Although even in the standard model, the electron at some energy level probably has a detectable dipole moment (e.g., the charge wouldn't be uniformly spherically distributed in the electron), it is my understanding that it is predicted to be too small to be validated by current experiments. However, some versions of super-symmetry apparently would predict that the electron at some energy levels would have a larger detectable dipole moment . I guess these super-symmetry predictions didn't pan out.
Re:What about size? (Score:2, Informative)
radius: 2.8179403267e-15 m
That is the classical answer. It is generally considered to be a point particle today.
Re:Has Anything Ever Validated Supersymmetry? (Score:5, Informative)
It's a little more involved. We know that the standard model is unable to explain a few important observations (such as gravity) so it *can't* be the whole story. Any theory that accounts for gravity and dark matter/energy will be more elegant by virtue of not having holes in it.
Supersymmetry could explain those things and fortunately makes a few predictions that we are now capable of testing. However, those aren't panning out so it must be revised and tested again. At least until someone comes up with something better to test.
Bad news for string theory (Score:5, Informative)
http://en.wikipedia.org/wiki/Supersymmetry [wikipedia.org]
A whole lot of PhD dissertations, physics publications, and academic careers are on the line over this. String theory is the current favorite and loop quantum gravity the underdog. The direction of theoretical particle physics could be radically altered if the LHC doesn't find evidence of supersymmetry.
Re:Wait, it has a shape? (Score:4, Informative)
Yes in a way you are correct.
"Thus, at non-relativistic energies the EDM [electric dipole moment] corresponds to a shift of energy levels of the electron in an external electric field E that depends on the direction of electron's spin Se. "
More details:
http://resonaances.blogspot.com.au/2013/11/electric-dipole-moments-and-new-physics.html [blogspot.com.au]
Re:Invisible unicorns in a garage (Score:5, Informative)
This is a good question. There are a number of theoretical and empirical motivations for supersymmetry, including the existence of dark matter, the matter-antimatter asymmetry in the universe, and the hierarchy problem in particle physics. I don't fully understand all of these myself. However, this short video released by my collaboration tries to explain some of them at a basic level: http://www.youtube.com/watch?v=UIflReRmynk.
Re:Invisible unicorns in a garage (Score:5, Informative)
It says that supersymmertry predicts a larger dipole moment, that's why it would be in question.
If you want to know why supersymmetry makes that prediction then you aren't going to get that in a new article or a slashdot post. There are lots of resources available for learning SUSY, or jump in the deep end with something random like http://www.springer.com/physics/particle+and+nuclear+physics/book/978-4-431-54543-9 [springer.com]