Symbol g_i

The passage around this formula

If the vacuum has a history of discrete jumps, a natural follow-up question is whether it also has a history of gradual drift — whether the constants fixed by electroweak symmetry breaking are quietly creeping away from their frozen values even now. This is a genuinely different physical question from phase transitions, and the Standard Model already contains a mild, well-understood version of scale dependence that should not be confused with time variation: coupling constants “run,” meaning their effective strength depends on the energy scale Q at which they are probed, governed by renormalization-group equations of the schematic form $Q\,\frac{dg_i}{dQ} = \beta_i(g_1, g_2, g_3, y_t, \lambda)$. where the $\beta_i$ are calculable…

Read this part in the article →