tag:blogger.com,1999:blog-7315236707728759521.post5409306111278213522..comments2024-03-27T22:28:06.861-06:00Comments on Dispatches From Turtle Island: Distinguishing the SM and SUSY With Running Coupling Constants At The LHCAndrew Oh-Willekehttp://www.blogger.com/profile/02537151821869153861noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-7315236707728759521.post-52707304815890195562014-10-28T08:45:27.806-06:002014-10-28T08:45:27.806-06:00An up to date discussion of these prospects at LHC...An up to date discussion of these prospects at LHC with respect to the electromagnetic and weak force coupling constants is found <a href="http://arxiv.org/pdf/1410.6810.pdf" rel="nofollow">here</a>. It confirms that accuracy to the percent level in the 1 TeV-10 TeV energy scale range would be sufficient to distinguish many models including supersymmetric models with reasonably light superpartners from the SM.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-23535172610687888322014-01-31T17:47:41.857-07:002014-01-31T17:47:41.857-07:00The gist of the argument is that we start out in a...The gist of the argument is that we start out in a low, perhaps even minimal entropy state at the big bang and that the Heisenberg uncertainty principal and the stochastic rather than deterministic character of the laws of nature is what disturbs the symmetry. This is certainly what conventional wisdom uses to explain the ansisotropic distribution of matter in the universe and there is an analogy to symmetry breaking in forces.<br /><br />It is really hard to see gauge coupling unification as an argument against supersymmetry and GUTs. It is one axiom among many possible ones that one could choose, but not an implausible axiom, given the reasonably close approximation to it seen in the SM and the already deep connections that exist between the electric and weak forces.<br /><br />Some very interesting arguments focus on unifying gravity and the weak force before trying to unify the strong force with the electroweak.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-92025134868647969752014-01-31T08:42:20.056-07:002014-01-31T08:42:20.056-07:00Thanks for the summary of the present state of tes...Thanks for the summary of the present state of testing the coupling constants as well as discussion of what's likely to be measurable in the near at the LHC.<br /><br />I just want to point out my own opinion, which is that I see no reason why all of the force coupling constant should be exactly equal at really high energies.<br />Like physicist Joe Rosen, I don't believe in the concept of "symmetry breaking." For example, a ball on a Mexican hat is an often given example in which a ball starts in a symmetry state and then ends up in state that is not rotationally symmetry. However, this is not a good example because if the ball really were in a symmetric state, it could rest on top of the hat. It's only because there is some force (such as the wind) that is not rotationally symmetric or because the ball wasn't actually located at the center of the hat that could cause ball to have a non-rotationally symmetric end state.<br />In words, there much have been something asymmetric long before the ball ended in an asymmetric state. Or put another way, the symmetric state of the total system can't decrease. On the hand, there are cases when the symmetry of the system increases with time, such as when a group of molecules is started in one corner of a box, and over time, the molecules reach a symmetric distribution across the box. The same holds for electrical charges places on the surface of a metal sphere.<br /><br />As Joe Rosen puts it, the symmetry of the universe can only increase. And as such, I'm highly skeptical of the concept of symmetry breaking. Small asymmetries can turn into large asymmetries, but something perfectly symmetric can't turn into something asymmetric.<br />As such, I'm skeptical that the laws of physics could start out with higher symmetry in the past than they have in the future. For example, if the symmetry of space-time translation existed in the past, then I don't see how it could be broken in the future. Space-time translation symmetry (i.e. momentum-energy conservation) either is a symmetry of the universe or it isn't. I think that the same goes for the symmetry of the laws themselves. If the current laws have symmetries of U(1), SU(2) and SU(3), then in the past the symmetry state of the laws couldn't have been higher in the past (i.e. some Grand Unified Symmetry state like E8 or SU(6).) The symmetry state of the past could only have been less symmetric than the future.<br /><br />Here's another example. Right now, there is no space-time reflection symmetry, but it's entirely possible that the universe could reach a global equilibrium and there would be space reflection symmetry. As such, the overall symmetry of the universe would have increased. It appears that we live in a universe in which the total symmetry of the universe can increase (or remain constant), but can't decrease.<br /><br />And hence, one of the "arguments" supposedly for supersymmetry & GUT is, in my opinion, actually an argument against supersymmetry & GUT.Anonymousnoreply@blogger.com