A new measurement of the antiproton-to-proton flux ratio up to 100 GeV in the cosmic radiation

TL;DR

This paper reports a precise measurement of the antiproton-to-proton flux ratio in cosmic rays up to 100 GeV, providing important data to understand cosmic ray origins and constrain exotic sources like dark matter.

Contribution

It presents the first high-statistics measurement of the flux ratio up to 100 GeV, improving previous data by an order of magnitude and constraining exotic contributions.

Findings

Results follow secondary production expectations

Data significantly constrain dark matter annihilation models

High-energy measurements are ten times more precise than previous ones

Abstract

A new measurement of the cosmic ray antiproton-to-proton flux ratio between 1 and 100 GeV is presented. The results were obtained with the PAMELA experiment, which was launched into low-earth orbit on-board the Resurs-DK1 satellite on June 15th 2006. During 500 days of data collection a total of about 1000 antiprotons have been identified, including 100 above an energy of 20 GeV. The high-energy results are a ten-fold improvement in statistics with respect to all previously published data. The data follow the trend expected from secondary production calculations and significantly constrain contributions from exotic sources, e.g. dark matter particle annihilations.