Effective action of 6D F-Theory with U(1) factors: Rational sections make Chern-Simons terms jump

Understand

We derive the six-dimensional (1,0) effective action arising from F-theory on an elliptically fibered Calabi-Yau threefold with multiple sections.

• The considered theories admit both non-Abelian and Abelian gauge symmetries.
• Our derivation employs the M-theory to F-theory duality in five-dimensions after circle reduction.
• Five-dimensional gauge and gravitational Chern-Simons terms are shown to arise at one-loop by integrating out massive Coulomb branch and Kaluza-Klein modes.