Heading to Oxford today, this evening I’ll give a talk there on Unified Theories of Physics. On Saturday I’ll try to find some way to get to the HTLGI Festival in London despite a national rail strike, where I’ll give a talk on Saturday and be on two panel discussions Sunday.
I’ll post slides after the talk tonight, one theme of which will be the failure of a series of attempts to extend the Standard Model, all of which were started in the mid-1970s (GUTs, SUSY, string theory). An opinion piece by Sabine Hossenfelder appeared yesterday in the Guardian, which takes a similar point of view on the current fate of extensions of the SM, but I strongly disagree with a lot of what she has to say.
The bad theory activity she points to has been going on for decades, but in recent years it seems to me to be a lot less popular. Most influential theorists have (quietly) agreed with her that particle physics is dead. In attacking bad model building in particle physics, I think she’s going after a small group of stragglers, not the center of theoretical activity (which has problems much more worth discussing).
What I most disagree with her about though is her treatment of HEP experiment and experimentalists. Yes, one can find people who have used bad theory to make bad arguments for building a new machine, but I don’t think those have been of much significance. For more on the current debate about this, see here. At the present time though, no one is spending money on building a new energy frontier machine any time soon. Money is being spent on running the LHC at high luminosity (CERN) and studying neutrinos (US), as well as studying the possibilities for going to higher energy. All of these activities are valuable and well-justified.
The LHC has been a huge success so far, with the old claims that it was going to see extra dimensions an embarrassment which doesn’t change the science that has happened. The discovery of the Higgs was a huge advance for the field, and the on-going effort to study its properties in detail is important. Another huge advance for the field has been the careful investigation of the new energy range opened up by the LHC, shooting down a lot of bad theory. Pre-LHC, the most influential theorists in the world heavily promoted dubious SUSY extensions of the SM, making these arguably the dominant paradigm in the field. LHC experimentalists have blown huge holes in that bandwagon, in some sense by doing exactly what Hossenfelder complains about (looking for evidence of badly motivated theories of new particles). In this story they’re not the problem, they’re the solution.
I’ll be busy this week with the talks mentioned and with attending math talks in Oxford, so little time to discuss more here or do a good job moderating a discussion. So, behave.
Update: The slides from the Oxford talk are here.
Update: Sabine has a blog entry more carefully explaining her point of view here.
Update: Some coverage of this at Physics World.