PAMELA Positron Excess as a Signal from the Hidden Sector

TL;DR

This paper explains the positron excess observed by PAMELA using a hidden sector model with an extra gauge field, predicting dark matter annihilation signals consistent with multiple experiments and testable at the LHC.

Contribution

It introduces a Stueckelberg extension of the standard model with a hidden sector that accounts for the positron excess and dark matter constraints.

Findings

Hidden sector matter can produce the observed positron excess.

Model predictions fit the $ar p/p$ flux ratio data.

Testable predictions at the Large Hadron Collider.

Abstract

The recent positron excess observed in the PAMELA satellite experiment strengthens previous experimental findings. We give here an analysis of this excess in the framework of the Stueckelberg extension of the standard model which includes an extra $U(1)_X$ gauge field and matter in the hidden sector. Such matter can produce the right amount of dark matter consistent with the WMAP constraints. Assuming the hidden sector matter to be Dirac fermions it is shown that their annihilation can produce the positron excess with the right positron energy dependence seen in the HEAT, AMS and the PAMELA experiments. Further test of the proposed model can come at the Large Hadron Collider. The predictions of the $\bar p/p$ flux ratio also fit the data.