The Standard Model of particle physics (SM) has been very successful at describing the elementary particles and the forces that bind them together. However, the Standard Model presents some significant problems for big bang theorists. This is because the SM does not contain any Dark-Matter particles, and the neutrinos in it are described as exactly massless. Which means that in its present form, it is in clear contradiction with the big bang model as required by various observations.
Those observations have led to the need to include Dark Matter in the standard (ΛCDM1) big bang model, particularly during the period of nucleosynthesis, just after the big bang beginning when the light elements were allegedly formed from hot hydrogen. Therefore, the Standard Model of particle physics is in stark disagreement with the requirements necessary for the formation of the first elements in the alleged big bang.
Where are the Dark-Matter particles?
All challenges to the standard ΛCDM big bang model have been met and overcome, so far, by assuming ‘unknowns’ particularly Dark Matter and Dark Energy, wherever and whenever needed. Astronomical observations have led big bang astronomers and cosmologists to look for these new unknown Dark-Matter particles to solve many of their problems resulting from such observations; for example, the formation of stars, galaxies and galaxy clusters, the testing of the big bang model with type Ia supernova measurements, the angular power spectrum of the CMB anisotropies, galaxy rotation curves, and in particular, as focussed on here, Big Bang Nucleosynthesis (BBN).2