Very light posting recently, partly due to being busy keeping up with my class, but more due to just not noticing anything particularly newsworthy. Matt and Lubos have quite a lot to say about Time magazine’s not describing the Higgs mechanism accurately, but I find it hard to get too excited about that, with my sympathies lying with any poor journalist given the impossible task of explaining this in a few words to the public.
Today at CERN there’s an LHCC meeting, with status reports on the machine and the experiments available here. The 8 TeV proton-proton physics run has just about ended, with the next week or so to be devoted not to luminosity production, but to machine studies. The integrated luminosity for the run will be about 23 inverse femtobarns, significantly above the original plan for the year. A heavy-ion run will end in February, after which the machine will be shut down for a long period in order to fix the magnet interconnects and other problems, to allow running at or close to the design energy of 7 TeV/beam. The current plan has proton-proton physics at 6.5 TeV/beam starting again about April 2015.
It seems likely that there will be no new results about the Higgs until the Moriond conference in March. CMS and ATLAS will then have quite a while to work on doing the best possible analysis of their 7 and 8 TeV data for information about the Higgs. From now on, attention will focus on what CMS and ATLAS have to say about the signal sizes in the various channels where the Higgs is supposed to show up, as well as theoretical studies of how possible next generation accelerators would perform in terms of doing better at these measurements than the LHC. The LHC Higgs Cross Section working group is meeting today and tomorrow on this topic, talks are available here. Next week the KITP will host a similar workshop.
The continuing big story from the LHC is that of no SUSY or other BSM physics showing up. The LHCC ATLAS slides have
Physics beyond the SM did not show up yet. There is no need for preliminary conclusions. Let’s continue our work and look were we haven’t looked so far.
but theorists are definitely starting to draw preliminary conclusions, needed or not. At Scientific American, Glenn Starkman has a piece entitled At CERN: Down in the Mouth in Paradise which paints a sorry picture of the situation caused by SUSY not showing herself:
The Standard Model is absurdly fine-tuned, we were told – balanced on a knife-edge off which it has no right not to tumble. It has an un-natural hierarchy of scales. It has too many free parameters, and some of them are very, very small. Why, the electron mass is less than 0.00001 times the weak scale (the energy scale governing weak interactions such as the W and Z boson masses), which is itself 10-17 (that 0.0000000000000001) times the Planck scale (the energy scale governing gravity)! And speaking of gravity, the Standard Model can’t accommodate quantum gravity. We need Low-Energy Supersymmetry, or Technicolor, or Large Extra Dimensions, or … One of these MUST be found at the LHC!
Forty years of theoretical work has been based on these expectations. Papers with thousands of citations have been written. Courses taught. Textbooks published.
Prizes awarded! Illustrious careers navigated! And yet despite all this build up of theoretical expectations, there is no experimental hint of anything outside the Standard Model at the LHC. Hence the long faces and worried words wherever theorists gather to drink coffee. Hence the disappointment in the eyes of the young experimentalists looking forward to the next accelerator, the next frontier where their mark will be made…
Walk the halls, go to theory seminars, have lunch with a theorist, or an ambitious young experimentalist. Look for the classic symptoms of grief.
Denial. Vigorous debates about whether the fact that the dog did not bark in the night suggests that it is a Chihuahua or a Rottweiler. My friends – at some point if there is no barking, we must conclude there is no dog.
Anger. At those of us “misguided” enough to doubt the imminence or even the necessity of Beyond the Standard Model physics.
Bargaining. Perhaps BSM physics has not been discovered because we’ve been demanding too much explanatory power from science. If we just relax our expectations for the predictivity of science, and introduce a multitude of universes in which we occupy a particular one best suited to our existence, then we can let our extensions to the Standard Model be un-natural, many of their properties unpredictable, and explain why they haven’t been discovered yet!
We’re not ready for Acceptance! At least, sitting here listening to the LHC hum, I can still hope.
Last Updated on