Universal contributions to scalar masses from five dimensional supergravity

TL;DR

This paper analyzes scalar mass generation in warped 5D supergravity, revealing the necessity of including massive gravity exchanges, and finds that most configurations lead to tachyonic masses unless additional bulk fields are introduced.

Contribution

It demonstrates the importance of massive gravity multiplet exchange in 4D effective theories and explores how bulk fields influence scalar mass spectra in warped supergravity models.

Findings

Zero scalar masses in extreme localization limit.

Most configurations produce tachyonic scalar masses.

Bulk vector multiplets can generate positive scalar masses.

Abstract

We compute the effective Kahler potential for matter fields in warped compactifications, starting from five dimensional gauged supergravity, as a function of the matter fields localization. We show that truncation to zero modes is inconsistent and the tree-level exchange of the massive gravitational multiplet is needed for consistency of the four-dimensional theory. In addition to the standard Kahler coming from dimensional reduction, we find the quartic correction coming from integrating out the gravity multiplet. We apply our result to the computation of scalar masses, by assuming that the SUSY breaking field is a bulk hypermultiplet. In the limit of extreme opposite localization of the matter and the spurion fields, we find zero scalar masses, consistent with sequestering arguments. Surprisingly enough, for all the other cases the scalar masses are tachyonic. This suggests the holographic interpretation that a CFT sector always generates operators contributing in a tachyonic way to scalar masses. Viability of warped su- persymmetric compactifications necessarily asks then for additional contributions. We discuss the case of additional bulk vector multiplets with mixed boundary conditions, which is a partic- ularly simple and attractive way to generate large positive scalar masses. We show that in this case successful fermion mass matrices implies highly degenerate scalar masses for the first two generations of squarks and sleptons.