Measurement of the cosmic-ray antiproton-to-proton abundance ratio between 4 and 50 GeV.
PHYSICAL REVIEW LETTERS 2001;
87:271101. [PMID:
11800867 DOI:
10.1103/physrevlett.87.271101]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2001] [Revised: 10/16/2001] [Indexed: 05/23/2023]
Abstract
We present a new measurement of the antiproton-to-proton abundance ratio, pbar/p, in the cosmic radiation. The HEAT-pbar instrument, a balloon borne magnet spectrometer with precise rigidity and multiple energy loss measurement capability, was flown successfully in Spring 2000, at an average atmospheric depth of 7.2 g/cm(2). A total of 71 antiprotons were identified above the vertical geomagnetic cutoff rigidity of 4.2 GV. The highest measured proton energy was 81 GeV. We find that the pbar/p abundance ratio agrees with that expected from a purely secondary origin of antiprotons produced by primary protons with a standard soft energy spectrum.
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