The Weak Gravity Conjecture and axion strings

Journal of High Energy Physics

Matthew Reece¹  Tom Rudelius²  Ben Heidenreich³ 

[1] Department of Physics, Harvard University, 02138, Cambridge, MA, USA;Department of Physics, University of California, 94720, Berkeley, CA, USA;Department of Physics, University of Massachusetts, 01003, Amherst, MA, USA;

关键词: Effective Field Theories;    Gauge Symmetry;    Models of Quantum Gravity;    String theory and cosmic strings;   

DOI  :  10.1007/JHEP11(2021)004

来源: Springer

【 摘 要 】

Strong (sublattice or tower) formulations of the Weak Gravity Conjecture (WGC) imply that, if a weakly coupled gauge theory exists, a tower of charged particles drives the theory to strong coupling at an ultraviolet scale well below the Planck scale. This tower can consist of low-spin states, as in Kaluza-Klein theory, or high-spin states, as with weakly-coupled strings. We provide a suggestive bottom-up argument based on the mild p-form WGC that, for any gauge theory coupled to a fundamental axion through a θF ∧ F term, the tower is a stringy one. The charge-carrying string states at or below the WGC scale gMPl are simply axion strings for θ, with charged modes arising from anomaly inflow. Kaluza-Klein theories evade this conclusion and postpone the appearance of high-spin states to higher energies because they lack a θF ∧ F term. For abelian Kaluza-Klein theories, modified arguments based on additional abelian groups that interact with the Kaluza-Klein gauge group sometimes pinpoint a mass scale for charged strings. These arguments reinforce the Emergent String and Distant Axionic String Conjectures. We emphasize the unproven assumptions and weak points of the arguments, which provide interesting targets for further work. In particular, a sharp characterization of when gauge fields admit θF ∧ F couplings and when they do not would be immensely useful for particle phenomenology and for clarifying the implications of the Weak Gravity Conjecture.

【 授权许可】

CC BY