I was thinking about Alejandro’s minor mystery (which I’ve never heard stated before), and decided to make a plot, which can be found at

http://hepr8.physics.tamu.edu/pivarski/tmp/qcd.svg

It’s a histogram of all unflavored QCD meson masses (everything made of a pair of up and down quarks) known to the PDG. By the way, “GeV” ought to be “MeV.”

Indeed, the pion is a lightweight outlier, and it’s very close to the muon mass. Without chiral symmetry breaking, the pion’s mass would be zero, further singling it out as special.

The third generation of the electron family, tau, is in the middle of the unflavored QCD spectrum. I wouldn’t read anything from the fact that it’s in the middle: the shape of that distribution mostly depends on experimentalists’ ability to identify these as individual particles. Many of these “particles” are broad peaks and interfere strongly with their neighbors— two particles with the same mass can interfere constructively to look like one particle with a strong signal, destructively to look like nothing at all, or, more generally, make a very complicated curve that’s difficult to fit.

You know, if we expected electron (0.5 MeV), muon (105 MeV), and tau (1770 MeV) masses to resemble the down-type quark masses, down (5 MeV), strange (95 MeV), and bottom (4500 MeV), only the last one is rather far off. in fact, the down-type/lepton agreement is better than the down-type/up-type agreement: up (2 MeV), charm (1250 MeV), and top (175000 MeV). Both patterns diverge mostly in the third generation. In the Higgs mechanism, these patterns derive from Higgs coupling strengths, which looks about right to me, especially in supersymmetry, where there’s one Higgs for down-type and another for up-type particles.

Cheers,
T.

In my last experiment, I carefully measured decay constants of the well-known Upsilon particles. It was gratifying to see all the tiny effects fall into place— I still had a lingering doubt that physics somehow wasn’t real. But in this next project, I want to search for something unknown, because it’s more exciting that way. Everyone has to tune their preferred ratio of excitement to probability of wasting their time.

The arguments people make that they are not wasting their time, based on naturalness or quadratic divergences or unitarity, are valuable, because without these quantitative hints we would have no guide at all. But we all know that they are a different thing from evidence.

The qualitative imagery newspapers usually use to describe this process involves thinking about the Higgs field as molasses, with particles struggling to accelerate through it, thus explaining inertial mass. I’m uncomfortable with this analogy because drag forces are always a function of velocity, and will slow a particle to a stop, relative to the ambient fluid.

Even worse: the analogy of inertial mass increase and length contraction by the ’snowplow’ effect of a particle moving in the Higgs field which can’t quite get out of the way fast enough as the particle speed is increased. This nonsense is even more disconcerting, because it destroys the reliance on the mathematical beauty of special relativity, supplying a mechanism.

It’s a step backwards towards FitzGerald’s discovery of the contraction in 1889 and Lorentz’s development of it in 1893, whereby bodies get contracted for a physical reason (pressure in the direction of motion). It’s far better to pretend that special relativity is the basis of general relativity, instead of an approximation made by absurdly assuming in general relativity that the mass-energy of the universe is M = 0. Put M = 0 into the Schwartzchild metric and you get the Minkowski metric, thus general relativity is ‘built on special relativity’, by the same brilliant reasoning that ‘animals must be made of manure, since they produce manure.’ A very clever and useful deduction to make.

Moreover, the Higgs field is a key part of supersymmetry, grand unified theories, and almost everything that high-energy physicists are excited about.

Making superpartners conveniently too heavy to be observed is - like making extra spatial dimensions too small to be observed - an act of faith. We have to repect those who work as clowns, because they’re a hard act to follow.