A very sensitive search for cosmic-ray antihelium was performed using data obtained from three scientific flights of the BESS magnetic rigidity spectrometer. We have not observed any antihelium; this places a model-independent upper limit (95% C.L.) on the antihelium flux of 6 × 10-4 m2sr-1S-1 at the top of the atmosphere in the rigidity region 1 to 16 GV, after correcting for the estimated interaction loss of antihelium in the air and in the instrument. The corresponding upper limit on the He/He flux ratio is 3.1 × 106, 30 times more stringent than the limits obtained in similar rigidity regions with magnetic spectrometers previous to BESS.
|Number of pages||6|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|Publication status||Published - 1998 Mar 12|
ASJC Scopus subject areas
- Nuclear and High Energy Physics