AdS swampland conjectures and light fermions
Abstract
We consider constraints on Ddimensional theories in M_{D}, dS_{D} and AdS_{D} backgrounds in the light of AdS swampland conjectures as applied to their compactification in a circle. In particular we consider the nonSUSY AdS instability conjecture and the AdS distance conjecture. For M_{D} and dS_{D} vacua the results may be summarized by a light fermion conjecture which states that in theories with Λ_{D} ≥ 0 and a positive first nonvanishing supertrace ^{( 1) k + 1}StrM^{2k} > 0, a surplus of light fermions with mass m_{f} ≲Λ_{D}^{1/D} must be present. For dS_{D} this is supported by both AdS swampland conjectures. On the contrary, the cases of M_{D} and AdS_{D} can be made consistent with the mild but not the strong version of the AdS Distance conjecture, since the KK tower in the lower ddim theory will scale as m ≲ Λ_{d}^{α} with α = 1 / d. The above constraints also suggest that the Standard Model of particle physics would be inconsistent in Minkowski space but consistent in dS if the lightest neutrino is Dirac and lighter than the cosmological constant scale.
 Publication:

Physics Letters B
 Pub Date:
 November 2021
 DOI:
 10.1016/j.physletb.2021.136691
 arXiv:
 arXiv:2104.06415
 Bibcode:
 2021PhLB..82236691G
 Keywords:

 High Energy Physics  Theory;
 High Energy Physics  Phenomenology
 EPrint:
 Minor corrections. References added