Backreaction: The LHC “nightmare scenario” has come true.
For the last ten years you’ve been told that the LHC must see some new physics besides the Higgs because otherwise nature isn’t “natural” – a technical term invented to describe the degree of numerical coincidence of a theory. I’ve been laughed at when I explained that I don’t buy into naturalness because it’s a philosophical criterion, not a scientific one. But on that matter I got the last laugh: Nature, it turns out, doesn’t like to be told what’s presumably natural. Now that the diphoton bump is gone, we’ve entered what has become known as the “nightmare scenario” for the LHC: The Higgs and nothing else. Many particle physicists thought of this as the worst possible outcome. It has left them without guidance, lost in a thicket of rapidly multiplying models. Without some new physics, they have nothing to work with that they haven’t already had for 50 years, no new input that can tell them in which direction to look for the ultimate goal of unification and/or quantum gravity. That the LHC hasn’t seen evidence for new physics is to me a clear signal that we’ve been doing something wrong, that our experience from constructing the standard model is no longer a promising direction to continue. We’ve maneuvered ourselves into a dead end by relying on aesthetic guidance to decide which experiments are the most promising. I hope that this latest null result will send a clear message that you can’t trust the judgement of scientists whose future funding depends on their continued optimism. Things can only get better.