4 ms·
This makes it sound more ad hoc than it is, it's not some polynomial where people just tack on terms. In its current agreed upon form it's just SU(3)xSU(2)xU(1
by yummypaint 2y ago
This makes it sound more ad hoc than it is, it's not some polynomial where people just tack on terms.
In its current agreed upon form it's just SU(3)xSU(2)xU(1). This gauge symmetry defines the lagrangian, which has 19 parameters to be determined by experiment.
It's true that this isn't the whole story (dark matter etc), but these symmetries are physically motivated and their predictive power is pretty amazing (the QED part is CORRECT as far as any experiment has been able to check so far).