It's a pretty long one but I could not resist to read the whole text. How exciting! Apparently, he identifies the correct vacuum of string theory, and checks it numerically. He obtains various masses of quarks and leptons that seem to agree with observations. The accuracy of his calculations is thrilling. I was particularly impressed by the 6-loop correction to the muon Yukawa coupling and the D3-brane instanton that modifies the Weinberg angle at low energies.
There are many funny points about this paper. For example, in the acknowledgements, the author thanks Peter Woit for emphasizing the importance of the Dirac operator on the moduli space of Calabi-Yau four-folds and the importance of string theory to him. (F-theory on the Glashow Calabi-Yau four-fold is the picture in which he decided to calculate the neutrino mass matrix.)
This may be a pretty important paper, perhaps a second Nobel prize paper. Some of Glashow's points that go beyond the analysis of the particular (correct) model are the following:
- the landscape is a nonsense, and the vacua that do not have any kind of self-mirror discrete symmetries are eliminated from the initial Hartle-Hawking-like wave function of the Universe
- a particular sign in the HH wavefunction must be reverted
- the inflation is driven by 3 scalar fields in a hidden sector, and one gets about 64 e-foldings of inflation
- the cosmological constant is cancelled at the leading order due to a kind of hidden, broken N=2 supersymmetry; the spontaneous breaking of this symmetry generates vacuum energy of order "m_{SP}^8 / m_{string}^4"; the "m_{SP}^4" terms are trivially cancelled by the underlying broken "N=2" SUSY or, equivalently, the self-mirror discrete symmetry
- in Glashow's model, the superpartner scale, defined as the mass of the LSP (a neutralino), is about 200 GeV, and "m_{string}=8 x 10^14 GeV" (the heterotic string coupling)
- the vacua of string theory are not unique, but his vacuum is the only metastable 4D vacuum with completely broken supersymmetry
- Glashow identifies 3 main new decay channels for vacua that have been neglected so far - the most interesting one is a splitting of the internal manifold into disconnected manifolds, something that destabilizes virtually all type IIB flux vacua
He also proposes a new bootstrap principle that could be the ultimate formulation of string theory. Two-dimensional conformal field theories (perturbative string theory) and AdS/CFT-like theories represent two large classes of solutions of Glashow's bootstrap conditions.
I feel embarassed that I could not finish various concepts that Glashow completes so easily (although I was pretty close).
