Low-scale Inflation and Supersymmetry Breaking in Racetrack Models

TL;DR

This paper presents a low-scale inflation model within string theory racetrack scenarios, linking inflation to supersymmetry breaking, and discusses its phenomenological implications for particle physics and cosmology.

Contribution

It introduces a novel low-scale inflationary framework in racetrack models with magnetized D7-branes, connecting inflation, supersymmetry breaking, and observable particle physics.

Findings

Inflation occurs near a potential inflection point in the modulus.

Gravitino mass is set around 30 TeV to avoid BBN issues.

Gaugino and scalar masses are influenced by anomaly and modulus mediation.

Abstract

In many moduli stabilization schemes in string theory, the scale of inflation appears to be of the same order as the scale of supersymmetry breaking. For low-scale supersymmetry breaking, therefore, the scale of inflation should also be low, unless this correlation is avoided in specific models. We explore such a low-scale inflationary scenario in a racetrack model with a single modulus in type IIB string theory. Inflation occurs near a point of inflection in the K\"ahler modulus potential. Obtaining acceptable cosmological density perturbations leads to the introduction of magnetized D7-branes sourcing non-perturbative superpotentials. The gravitino mass, m_{3/2}, is chosen to be around 30 TeV, so that gravitinos that are produced in the inflaton decay do not affect big-bang nucleosynthesis. Supersymmetry is communicated to the visible sector by a mixture of anomaly and modulus mediation. We find that the two sources contribute equally to the gaugino masses, while scalar masses are decided mainly by anomaly contribution. This happens as a result of the low scale of inflation and can be probed at the LHC.