Particle physics question for Kelsey or anyone else that can answer.... Answered
I am finishing up the book I am reading on Dark matter, and Mr. Krauss mentions "spontaneous symmetry breaking" (not a hard concept) creating or producing spin-0 particles or scaler particles (Higgs Boson?). My question is, have any of these particles, as yet, been observed? The book I am reading is slighty dated, and so I am not even sure it is up to date on the vacuum energy postion towards dark matter and a flat universe.