Bounds on extra dimensions from micro black holes in the context of the metastable Higgs vacuum
Abstract
We estimate the rate at which collisions between ultrahighenergy cosmic rays can form small black holes in models with extra dimensions. If recent conjectures about false vacuum decay catalyzed by black hole evaporation apply, the lack of vacuum decay events in our past light cone may place new bounds on the black hole formation rate and thus on the fundamental scale of gravity in these models. For theories with fundamental scale E_{*} above the Higgs instability scale of the Standard Model, we find a lower bound on E_{*} that is within about an order of magnitude of the energy where the cosmicray spectrum begins to show suppression from the GreisenZatsepinKuzmin effect. Otherwise, the abundant formation of semiclassical black holes with short lifetimes would likely initiate vacuum decay. Assuming a Higgs instability scale at the low end of the range compatible with experimental data, the excluded range is approximately 10^{17} eV ≲E_{*}≤10^{18.8} eV for theories with n =1 extra dimension, narrowing to 10^{17} eV ≲E_{*}≤10^{18.1} eV for n =6 . These bounds rule out regions of parameter space that are inaccessible to collider experiments, smallscale gravity tests, or estimates of KaluzaKlein processes in neutron stars and supernovae.
 Publication:

Physical Review D
 Pub Date:
 March 2019
 DOI:
 10.1103/PhysRevD.99.063001
 arXiv:
 arXiv:1809.05089
 Bibcode:
 2019PhRvD..99f3001M
 Keywords:

 High Energy Physics  Phenomenology;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 High Energy Physics  Theory
 EPrint:
 10 pages, 5 figures