A Note on Gaugino Masses in Kaluza-Klein/Radion Mediated SUSY Breaking

Abstract

We review the equivalence of two approaches to study theories with gauge fields in extra spatial dimensions, namely the ``4D'' approach (with KK states) and the ``5D'' approach (with matching to the 4D theory at the compactification scale). In particular, we reiterate that there are two different power-law scalings of ``effective'' gauge couplings. In a supersymmetric framework with SUSY breaking in the radius modulus, i.e., the field which fixes the size of the extra dimensions, these two approaches seem to give gaugino masses at loop-level (with a possible enhancement due to large number of Kaluza-Klein states) (hep-ph/0008069), and tree-level (hep-ph/0008103), respectively. We show explicitly how this discrepancy can be resolved.

Comments: Latex, 14 pages. In the revised version (to be published in JHEP), the conclusions are slightly stronger. We now say explicitly (in the introduction, section 5 and summary) that the tree-level contribution to gaugino mass considered in hep-ph/0008103 was neglected in hep-ph/0008069. The loop contribution to gaugino mass discussed in hep-ph/0008069 and not included in hep-ph/0008103 can be comparable to the tree-level effect, but the loop correction to the gaigino mass formula in hep-ph/0008103 is small