Particle Masses: A Simple Rule from the Depths of Physics express
In the boiling broth of the newborn Universe, all particles lost their distinctions, like vegetables at hellish temperatures. Recovering that simple recipe is the goal of modern physics.
The SO(10) theory — an extension of the Standard Model — offers such a recipe. It unifies all forces and links the masses of any particles with a single formula. Scientists refined the model and achieved record accuracy: the computed masses matched experiment. It turned out that at the energy of the Big Bang, the main characteristics of particles become almost the same.
If the model is confirmed, we will understand what predetermines particle masses and take a step towards a unified theory of everything.
Original abstract
as written by the authors arXiv:2506.11806
We discuss the charged and neutral fermion masses and mixings in a supersymmetric SO(10) model with a minimal Higgs sector consisting of the multiplets $$10_H$$, $$45_H$$, and $$16_H + \overline{16}_H$$. In addition to the renormalizable Yukawa couplings involving the Higgs 10-plet, we include non-renormalizable Yukawa couplings, which are important for reproducing with good accuracy the observed masses and mixings in the quark and lepton sectors. We identify a preferred solution which is compatible with third family quasi-Yukawa unification, namely $$y_t \approx y_b \approx 0.73 y_{\tau}$$ at the unification scale, with the MSSM parameter $$\tan\beta \sim 58$$. Acceptable solutions with lower $$\tan\beta$$ values are also realized in our framework, and we provide an example with $$\tan \beta =10$$. Based on our fits, the masses for the three right-handed neutrinos turn out to be $$\left(M_1,M_2,M_3\right)\sim \left(10^9, 8\cdot 10^{12}, 9\cdot 10^{12}\right) \mathrm{GeV}$$. We briefly discuss the metastable and quasistable string scenarios that can be realized in this class of supersymmetric SO(10) models.
The predicted heavyweight neutrino is about 500 times more massive than the top quark — and the top quark itself weighs almost as much as an entire gold atom.
The film 'The Theory of Everything' is about the search for a single equation. Work on SO(10) is a real step towards Einstein's dream.