Turtle Sandwich Standard Model
Turtle Sandwich Standard Model
[A two-by-two grid, with a piece of bread next to the top left cell; a turtle shell next to the bottom left cell; lettuce, cheese, and tomato above the top left cell; and an turtle head enclosed in a circle above the top right cell.]
[Top left cell: an image of a sandwich.]
✔ CONFIRMED
[Top right cell: an image of a shell-less turtle sandwiched between two slices of bread.]
(?)
[Bottom left cell: an image of a turtle shell housing lettuce, cheese, and tomato - the contents of a sandwich.]
(?)
[Bottom right cell: an image of a turtle.]
✔ CONFIRMED
[Caption below the panel]
Our lab is working to detect the two missing pieces of the turtle-sandwich standard model.

This comic references particle physics. The Standard Model of physics explains the base particles and fields that make up the universe.  The elementary fermions of the standard model can be laid out in a 3×4 grid, with three " generations " of matter, each containing a quark with charge +⅔, a quark with charge -⅓, a lepton with charge -1, and a neutrino with charge 0.  The first generation contains the familiar up and down quarks, which make protons and neutrons, the electron, and the electron neutrino.  Each succeeding generation of matter is more massive than the one before, and only the first generation of particles occurs naturally on Earth; the others have only been created and identified in particle accelerator experiments (although they also arguably exist in various extreme places around the universe; for example, the strange quark is suspected to be a component of the denser parts of neutron stars).
Quarks were initially proposed by Murray Gell-Mann to simplify the " particle zoo " that physicists were discovering.  He found that the twenty-five or so mesons and hadrons that were known at that time could be organized into what he called the " eightfold way " by just three properties: spin , charge, and what he called " strangeness ".  He proposed that three quarks (and their corresponding antiquarks) governed these properties.  His chart had an empty space for what he called the omega baryon , and when a particle of the properties he predicted (including its mass) was discovered, his model received a lot of support.  The quark model was eventually extended to include six quarks, and as with the eightfold way, one of the lines of evidence in favor of what became known as the Standard Model is that it predicted the existence and masses of several particles, which have since been confirmed; the top quark 's mass was predicted in 1973, and experimentally verified in 1995, for example, and on the gauge boson side of the chart, the Higgs boson was discovered in 2012.
In this comic strip, sandwiches (lettuce, cheese, tomato, and possibly other fillings, surrounded by bread) and turtles (an aquatic reptile which wears an armored shell) are likewise proposed to not be "elementary" entities, but in fact combinations of 4 elementary parts, namely bread, fillings, reptile, and shell.  The narrator's lab is looking for the hypothesized "bread-shelled turtle" and "shell-coated sandwich".  In fiction, turtles' shells are often depicted as articles of clothing which they can remove at will, but in the real world, the shell is a part of the turtle's skeleton, so unless the narrator's lab is willing to commit extremely invasive surgery, they will never find a bread-shelled turtle, although they could much more easily take the shell of a dead turtle and put some sandwich fillings inside.
The failure to detect the bread-shelled turtle could be taken as evidence that the turtle-sandwich standard model is flawed -- perhaps turtles and sandwiches are elementary entities, or perhaps the elementary entities that make them are much smaller than is proposed here.  There is also the small matter that there are things besides sandwiches and turtles in the universe [ citation needed ] .  Alternatively, it could be taken as evidence that the bread-shelled turtle has an extremely high energy, and so does not exist under typical conditions of our universe.  This might be analogous to magnetic monopoles ; we would know one if and when we saw one (and many experiments have sought them out), and we believe we know how they would behave, but no such particle has ever been verifiably detected or created.
In the same vein, the lack of observation could be due to the instability of the arrangements. Turtleshell-turtle assemblies can last for more than 100 years, while bread-filling assemblies are indefinitely stable under sufficiently low energies . The two other arrangements may simply be formed rarely, and have a relatively short half-life.
The title text introduces more particle physics jargon, proposing that the "top and bottom" parts of the bread and/or shell have distinct " flavors ", and that there may be "strange" and "charm" variants as well (a reference to the higher-generation quarks -- strange and charm in the second generation, and top and bottom in the third).
Unlike the turtle-sandwich standard model, there are no particles predicted by our Standard Model that have not yet been detected; however, there are several gaps between the pure Standard Model and what we observe in reality, most notably the existence of gravity and the apparent asymmetry between the amounts of matter and antimatter in the universe.  For this reason, the Standard Model is generally considered to be somehow incomplete.
[A two-by-two grid, with a piece of bread next to the top left cell; a turtle shell next to the bottom left cell; lettuce, cheese, and tomato above the top left cell; and an turtle head enclosed in a circle above the top right cell.]
[Top left cell: an image of a sandwich.]
✔ CONFIRMED
[Top right cell: an image of a shell-less turtle sandwiched between two slices of bread.]
(?)
[Bottom left cell: an image of a turtle shell housing lettuce, cheese, and tomato - the contents of a sandwich.]
(?)
[Bottom right cell: an image of a turtle.]
✔ CONFIRMED
[Caption below the panel]
Our lab is working to detect the two missing pieces of the turtle-sandwich standard model.
