Anomalous U(1) Mediation in Large Volume Compactification

TL;DR

This paper investigates how anomalous U(1)_A gauge symmetry influences supersymmetry breaking and soft mass terms in large volume compactifications, revealing a new mediation mechanism via U(1)_A vector superfields.

Contribution

It introduces a novel U(1)_A mediated SUSY breaking mechanism in large volume scenarios, detailing how the vector superfield acts as a messenger and affects soft masses.

Findings

U(1)_A vector superfield mediates SUSY breaking to MSSM sector.

Soft scalar masses are of order m_{3/2}^2/8π^2.

Gaugino masses are suppressed by loop factors.

Abstract

We study the general effects of anomalous U(1)_A gauge symmetry on soft supersymmetry (SUSY) breaking terms in large volume scenario, where the MSSM sector is localized on a small cycle whose volume is stabilized by the D-term potential of the U(1)_A. Since it obtains SUSY breaking mass regardless of the detailed form of K\"ahler potential, the U(1)_A vector superfield acts as a messenger mediating the SUSY breaking in the moduli sector to the MSSM sector. Then, through the loops of U(1)_A vector superfield, there arise soft masses of the order of m_{3/2}^2/8\pi^2 for scalar mass squares, m_{3/2}/(8\pi^2)^2 for gaugino masses, and m_{3/2}/8\pi^2 for A-paramteres. In addition, the massive U(1)_A vector superfield can have non-zero F and D-components through the moduli mixing in the K\"ahler potential, and this can result in larger soft masses depending upon the details of the moduli mixing. For instance, in the presence of one-loop induced moduli mixing between the visible sector modulus and the large volume modulus, the U(1)_A D-term provides soft scalar mass squares of the order of m_{3/2}^2. However, if the visible sector modulus is mixed only with small cycle moduli, its effect on soft terms depends on how to stabilize the small cycle moduli.