We extract the anomalous part of the cosmic e± flux via a Bayesian likelihood analysis using 219 cosmic ray data points. First we show that serious tension exists between the e± fluxes and the rest of the data. Interpreting this tension as an effect of an anomalous component on the e±data, we infer the values of selected cosmic ray propagation parameters by excluding the e± data from the analysis. Based on these values we calculate background predictions with theoretical uncertainties for PAMELA and Fermi-LAT. We find a statistically significant deviation between the Fermi-LAT e− +e+ data and the predicted background even when systematic uncertainties are taken into account. Identifying this deviation as an anomalous e± contribution we show that increased precision is required to distinguish between various sources that may be responsible for this contribution.
|Name||Proceedings of Science|
|Publisher||Scuola Internazionale Superiore di Studi Avanzati (S I S S A)|
|Conference||36th International Conference on High Energy Physics, ICHEP 2012|
|Period||4/07/12 → 11/07/12|
- Dark matter
- Positron fraction
- Cosmic rays