Three established observations already sit outside the Standard Model table: neutrino…
PHYSICS · Multi-part · Fermi University Physics · Particle Physics & Quantum Fields · Beyond the Standard Model · Beyond the Standard Model
Particle Physics, Ch The Standard Model as a table you can predict from
Problem
Three established observations already sit outside the Standard Model table: neutrino oscillation, which requires neutrino mass while the table as originally written has none; galactic rotation curves, which point to unseen mass with no candidate entry in the table; and gravity, which has no entry in the table at all. A fourth observation is now put to the same test. The expansion of the universe is accelerating; this is measured from the dimming of distant type Ia supernovae with distance, and the acceleration is attributed to a dark energy density that dominates the present-day cosmic energy budget. No decay, scattering or collider measurement described so far bears on it.
((a)) State, in one line, the criterion that separates an observation that shows the table to be wrong from one that shows it to be silent, illustrating each with one of the neutrino-mass or galactic-rotation-curve cases above.
((b)) Apply that criterion to the accelerating expansion. Is the table wrong or silent on this observation? Say what kind of entry would have to be added to the table for it to no longer be silent on this point.
((c)) Name one of the other three observations listed above that belongs in the same category as the accelerating expansion, and say why it belongs there rather than in the other category.