Light stringy states and the g − 2 of the muon

Abstract

Abstract In this work, we evaluate the contributions to the anomalous magnetic moment of the muon ((g − 2) μ ) coming from light stringy states in a D-brane semi-realistic configuration. A scalar which couples only to the muon can have a mass sufficiently light to provide a significant contribution to the (g − 2) μ . This scenario can arise in intersecting D-brane models, where such light scalars correspond to the first stringy excitations of an open string stretched between two D-branes intersecting with a very small angle. In this article, we show that there is a region in the space of the geometric parameters of the internal manifold where such scalar light stringy states can explain (part) of the observed discrepancy in the (g − 2) μ . In a low string scale framework with M s ≳ 10 TeV, we show that an excited Higgs with mass O $$ \mathcal{O} $$ (250 MeV), living in an intersection with an angle of order O $$ \mathcal{O} $$ (10 −10), can provide a significant contribution of one-tenth of the (g − 2) μ discrepancy. This leads to a lower bound for the compact dimension where the branes intersect of order O $$ \mathcal{O} $$ (10 −8 GeV −1). We also study patterns in D-brane configurations that realize our proposal, both in three and four stacks models.

Keywords

• Extra Dimensions
• Multi-Higgs Models
• Specific BSM Phenomenology