152 research outputs found
CP violation and gravity as the weakest force
We argue that CP violation has rather dramatic impact on the "gravity as the
weakest force" conjecture. Namely we find that new ultraviolet scale must be
, where is an effective parameter
describing CP violation and is the gauge coupling constant. The bound
implies that CP-conserving limit is discontinuous, and possibly indicates that
the class of effective theories with strict CP conservation is inconsistent
with a fundamental theory incorporating quantum gravity. At the same time, the
mass hierarchy problem can be explained due to the smallness of the CP
violation, or so.Comment: 4 page
Diffeomorphism-invariant noncommutative gravity with twisted local Lorentz invariance
We propose a new theory of gravitation on noncommutative space-time which is
invariant under the general coordinate transformations, while the local Lorentz
invariance is realized as twisted gauge symmetry. Our theory is remarkably
simpler compared to the existing formulations of noncommutative gravity.Comment: 7 pages; v2 to be published in EJT
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