Originally the blog was going to center on mesons, events, bubble chambers, training scanners (women – thought to be better at spotting such things as small objects colliding in complex multi-dimensional ways ) to transcribe “events” into data and now as we begin to look at the experimental world after 1923, we are almost to the first hints of the mesons. In fact, the blog has reached 1923, where atomic models are spectroscopically intricate and can account for many levels of emissions. We will progress on to 1928 when quantum theories begin to seem complete and coherent…and then Cosmic Rays open a whole new set of problems, making the 1930s a wonderful period for people working on approximations and experimentation and a painful period for theoreticians.
But here is an image of an event from 1971:
This bubble chamber event, described for “scanner” personnel, is from the Fermi Lab training materials in 1971:
You can go in many different directions from such images of “events.” You can move toward the imagery of theories such as Feynman diagrams reveal…you can look into the technology of bubble chambers and data transcription…the many layers of computational phenomenology…the background…how the first particles were discovered and separated in theory and experimental practice from the aether…
So…
At first, I planned on having the chronological starting point of the blog be about 1930 as the first problems with mesons began to emerge in Cosmic Ray studies.
But to get at these problems, I needed to elaborate on the Compton Effect (i.e. how light quanta, specifically X-rays, impact electrons) and C. T. R. Wilson (who with his cloud chamber won the 1927 Nobel Physics Prize along with Compton) and the semi-classical Klein-Nishina phenomenological approximation of how the Compton Effect and other effects worked in Cosmic Ray showers and how Hans Bethe, Compton, Millikan, Oppenheimer and others dealt with the implications of these effects and their approximations. The reception of the Compton Effect brought up some of Einstein’s final revolutionary contributions to understanding quanta and that led back to…well 1905, when Einstein first suggested something along the lines of quanta and special relativity.
Once you are looking at the world as people imagined it in 1905 (with for me mostly the help of A. I. Miller’s historical work)…you realize what an utterly different place it was. The mechanical world picture of the late nineteenth century – built up fundamentally out of the imagery of hydraulic vortices and acoustic analogies – was not just in crisis in itself, but well on its way to discrediting all that the sciences had seemed to promise. It was believed that neurology (along with nearly anything else you could name that you might actually want to know about) concealed mysterious regions that could never be (“mechanically” ie “scientifically”) resolved. In 1905, two things seemed to offer some hope of unraveling how the universe worked in a non-mechanical way: the aether (an imponderable substance that filled everything and that carried or conveyed or sustained all coordinate systems, fields and energies) and the electron (an accessible, isolatable “ion” with some characteristics that were not-too-mysterious ).
The vast number of things that the aether was supposed to do…was…yes, amazing in itself and all the more amazing since apparently the nineteenth century had started out happily with five or six aethers and managed to reduce all that to one: the luminiferous aether, the aether that carried light (but also probably the fields that light arose from or interacted with). This (for me at least) highly problematic (or “recalcitrant” as Jaume Navarro’s (ed)Ether and Modernity describes it) “Epistemic Object,” the aether, led me in several not-necessarily well-coordinated directions: 1) to find the point where the aether started to show signs of decisively and definitely losing plausibility (which turns out to be around 1880) 2) to re-imagine how the aether began to change its functions (following Buchwald’s story in From Maxwell to Microphysics), 3) to look at what functions the aether was thought to have and why (this turns out to include “aether dragging” and I found that to be extremely strange) 4) to look at how proto-particle physics left the aether rather quickly as Special Relativity was worked out from 1905 to 1911.
So far the blog runs from leaving the aether ( — which pretty much has happened after dealing with the fantasy of the purely electromagnetic electron and how it fitted into the aether or not) almost to Special Relativity and the quanta of action (Planck’s constant, phenomenologically derived, but not understood) and light. Coming up next, after that…a quick look at the traditional Thompson-Rutherford-Bohr-Sommerfeld narrative of atomic models and the parallel Einsteinian work on quanta. Which would get us to about 1922 and the Compton Effect and from there into mesons. This brings up another direction that I was hoping to cover in this blog: some specific phenomenological lineages, the principle one being the line of work pursued by the Sommerfeld-Bethe-Schweber line, but also some side lines such as the Born-Oppenheimer connections and the Pais-Gell-Mannian approaches. There’s an added bonus in that these approaches add some routes into historiography since Schweber and Pais wrote extensive histories of particle physics.
Added on March 10, 2021: Still haven’t looked into the traditional Thompson-Rutherford-Bohr-Sommerfeld narrative of atomic models, but we have somehow reached 1923 mostly by following the experimental background of the Compton Effect. As a growing acceptance of the Compton effect spread slowly across the experimental, phenomenological (approximations) and theoretical realms of the physicists’ concerns, five themes emerged related to how this blog is supposed to be approaching the world of the mesons. First, we can say good-bye to the fading of the aether; it is pretty much as faded as it will ever be by 1923. Second, we can say hello to the proto-photon as it emerges from the work of Einstein and Schroedinger and immediately runs into trouble with Bohr and the BKS theory which picture emission and absorption as acting in a virtual, statistically-governed region resembling a tiny patch of the old energy-storing aether. Third, as Schroedinger and Born get a handle on probability amplitudes, the amplitude approach immediately runs into trouble with Bohr and Heisenberg’s “Copenhagen Interpretation” much to the confusion of a century of quantum mechanists. Fourth, new techniques for partially quantized approximation emerge (such as the Born and Klein-Nishina) just in time to deal with a steady rise in the energies that experiments can deal with. And fifth, with the working out of field theories, new levels of theoretical approximations and refinements via perturbations and paths are developed – which gets us to the mid-1960s which is as far as this blog is going to go.