Gaugino and Scalar Masses in the Landscape

TL;DR

This paper shows that in the IIB string landscape, gaugino masses are generically suppressed relative to the gravitino mass, with a small hierarchy maintained across various moduli stabilization scenarios, impacting phenomenology.

Contribution

It demonstrates the genericity of suppressed gaugino masses in the IIB landscape and calculates scalar and gaugino masses explicitly for large-volume compactifications.

Findings

Gaugino masses are suppressed by a logarithmic factor in the landscape.

Scalar masses are approximately universal with small non-universality.

The suppression relation holds for models with multiple moduli and different stabilization methods.

Abstract

In this letter we demonstrate the genericity of suppressed gaugino masses M_a \sim m_{3/2}/ln(M_P/m_{3/2}) in the IIB string landscape, by showing that this relation holds for D7-brane gauginos whenever the associated modulus is stabilised by nonperturbative effects. Although m_{3/2} and M_a take many different values across the landscape, the above small mass hierarchy is maintained. We show that it is valid for models with an arbitrary number of moduli and applies to both the KKLT and exponentially large volume approaches to Kahler moduli stabilisation. In the latter case we explicitly calculate gaugino and moduli masses for compactifications on the two-modulus Calabi-Yau P^4_[1,1,1,6,9]. In the large-volume scenario we also show that soft scalar masses are approximately universal with m_i^2 \sim m_{3/2}^2 (1 + \epsilon_i), with the non-universality parametrised by \epsilon_i \sim 1/ln (M_P/m_{3/2})^2 \sim 1/1000. We briefly discuss possible phenomenological implications of our results.