Tonight, the most interesting paper on hep-th is undoubtedly
about the representation theory of sl(2/1). However, let me mention an even more interesting paper on hep-ph. It has been exactly one month since Shelly Glashow identified the correct vacuum of string theory and completed the theory of everything. Some readers have complained that even though the abstract looked fine, the paper itself was not available - and they conjectured that the paper may be related to the date April 1st.
One month later, the bug has been fixed. Today you can access both the new abstract as well as the new paper. The paper is again the last paper of the month, its number is
and it is about "A sinister extension of the Standard Model". To be sure, the PDF file is here. Many people like to talk about supersymmetry. Shelly (together with Andy Cohen) likes a different symmetry, namely
Terasymmetry assigns new terafermions - such as teraquarks and teraleptons - to all known fermions (they have the same statistics). The ordinary fermions and the terafermions are related by an unusual tera-CP symmetry which I call terasymmetry. The usual CP symmetry is not imposed at any level. Because the terafermions are heavy - where the masses softly break the terasymmetry - the strong CP violation is naturally eliminated and the theta angle is small. The mass ratios of terafermions match those of ordinary fermions - a teramuon is 206.8 times heavier than a teraelectron. However, the terafermions themselves must be at least roughly 1 million times heavier than the usual fermions - well, this itself looks like another fine-tuning.
As a bonus, terahelium is a good dark matter candidate and neutrinos acquire reasonable Dirac masses via a seesaw mechanism. After a quick look, I agree that such an approach is a rather natural answer to the strong CP problem - but I may change my mind after more careful considerations.