Measurement of cosmic antiprotons with the alpha magnetic spectrometer aboard the International Space Station

A precision measurement of the cosmic antiproton ( -p) flux and the antiproton-to-proton flux ratio ( -p/p) made with the Alpha Magnetic Spectrometer aboard the International Space Station is presented. The measurement covers the absolute rigidity range from 1 to 450 GV, and is based on 3.49x105 -p events and 2.42x109 proton (p) events. This completes the measurements of the fluxes and flux ratios for the charged elementary particles in cosmic rays by AMS. In the absolute rigidity range 60 to 500 GV, the -p , p, and positron (e+) fluxes are found to have nearly identical rigidity dependence. This contrasts with the electron (e-) flux, which exhibits a different rigidity dependence. Below 60 GV, the ( -p/p), ( -p/e+), and (p/e+) flux ratios each reach a maximum. From 60 to 500 GV, the ( -p/p), ( -p/e+), and (p/e+) flux ratios show no rigidity dependence. These are new observations on the properties of charged elementary particles in cosmic rays.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2017

Author dc:creator

• Chen, Andrew Ian

Advisor dc:contributor.advisor

• Samuel Ting.

• Physics.

Statement dc:rights

• MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/115001

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/115001